No.48 September 2006 |
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The environment of the Olympic Games: An Introduction
Abstract
Environmental factors can have an impact on performance in major sports
tournaments. The history of the modern Olympic Games illustrates how
environmental aspects influence the outcomes. Such factors have included
air quality (St Louis), pollution (Los Angeles), altitude (Mexico),
heat (Rome), for example. Travel schedules and jet-lag syndrome were
considerations for most nations competing in Sydney 2000, due to the
disharmony between local time and “body clock time” after
arrival in Australia. Acknowledging the potential for degrading competitive
performance, many competitors prepare coping strategies by acclimatisation,
acclimation or behavioural means. Weather conditions are unpredictable
well in advance and can deviate substantially from average climatic
data. Air ions and electric storms may have differential effects on
competitors and spectators. Contemporary athletes use projections for
Athens 2004, targeting heat and pollution as potential stressors. A
range of pollutants is also relevant to consider for Beijing, 2008.
Ecological issues have influence also, notably in the legacy left behind
for host cities.
Key words: Air quality, altitude,
heat, pollution, weather.
An Interdisciplinary Approach
Environmental factors have been relevant considerations in the modern
Olympic Games since the reinstallation of the Summer Olympics in 1896.
Physiological stressors have featured most prominently according to
climatic and local conditions. The history of the Olympic Games is marked
by examples of how performances are influenced by environmental variables.
In the events of the first half of the 20th Century, little was done
to take possible environmental extremes of heat into consideration when
planning the competitive schedule (4).
The modern Olympics have grown in scale as well as appeal. Hosting
the Games affords huge benefits for the organising nation, usually acquiring
a legacy of resources and facilities (and sometimes debt) for its own
community. The venues and installations change the local landscape in
a way not otherwise possible. The local infrastructure is transformed
in a major way to represent a huge economic investment for the future.
The global appeal of the Games raises its own pressures for related
commercial applications. Inevitably, there is a question about the Summer
Olympics (and Paralympic Games) as to whether its scale has outstripped
its ideals.
These considerations provide a background for treating environmental
issues in an interdisciplinary framework. The environment is interpreted
liberally for this purpose. Broad ecological questions may be raised
alongside known effects on athletes interacting with the Olympic environment.
In order to demonstrate the relevance of discrete environmental stresses,
some examples are first given from previous Games. These include heat,
altitude, travel stress and air pollution. Heat
It is clear that performance in events that entail high heat storage
may be degraded in hot conditions. Stresses are accentuated when high
relative humidity impairs evaporative heat loss. A radiant heat load
may further accentuate the strain on the athlete.
There are may instances of torrid conditions prevailing at the Olympic
Games, most notably in the men’s marathon. The event at Paris
in 1900 has been described as the “hottest Olympic marathon in
history” (3). Race-time temperature was reported as between 35ºC
and 39ºC. The extremely hot spell was a continuation of what had
been a very warm summer throughout France that year. Of the 16 starters,
only seven finished the course which at this time was over a distance
of 40.26 km.
There have been later instances of heat influencing performance of
Olympic competitors. Acknowledging the potential for negative impact
on performance, many athletes prepare coping strategies by using warm-weather
camps to gain the benefits of physiological acclimatisation. Such benefits
may also be acquired by periodic use of environmental chambers for simulating
hot conditions, the process being referred to as acclimation (5). There
is also something to be gained from experiencing the hot conditions
(even if there is insufficient exposure time for physiological acclimatisation)
so that the athlete may devise a strategy to cope in competition.
Projections for climatic conditions utilise meteorological databases
which may differ in detail from the competitive locations. Weather conditions
are inherently variable, are not highly predictable well in advance
and can at any time vary from the average climatic data provided by
meteorological sources. Nevertheless, sports science support programmes
utilise climatic data to prepare their athletes for exercise in the
heat. It is likely that the vast majority of competitors at the 2004
Olympic Games will have benefited from sport-specific advice about how
the environment in Athens might impact upon their performance. Altitude
Altitude is a common feature of the Winter Olympics, the winter sports
being associated with mountainous environments. The single instance
of altitude stress at the Summer Olympics was in Mexico, 1968. The results
from the Games demonstrated how performances in events largely dependent
on the oxygen transport system were impaired. In contract, the reduced
air density at altitude helped to enhance performance in sprint races
of up to an including 400 m and in the horizontal jumps (see Table 1).
All medallists in track-and-field at the Mexico Olympics in events
over 800 m and longer were either born or had trained at altitude. Subsequently
attention shifted from how to cope with competing at altitude to exploiting
the physiological adaptations to altitude in order to aid performance
at sea level. This change in emphasis has led to the widespread use
of altitude training camps in preparation for major tournaments. The
practice is now adopted across a range of sports including swimming
and rowing as well as running and cycling.
The use of altitude as a training stimulus has been extended to incorporate
altitude chambers located at sea-level. These may be the so-called “altitude
huts” or normobaric hypoxic chambers. Commercially available mobile
simulators alter the inspired oxygen tension to allow exercise hypoxia
to be experienced. Another resource is represented by the hypoxic tents
which allow the athlete to sleep in an enclosed environment with reduced
partial pressure of the oxygen being breathed in. This places emphasis
on habitual activity and living at altitude rather than training in
it. In view of the fact that the absolute exercise intensity is usually
reduced at altitude, an alternative strategy that is advocated for athletes
is to live for sojourns at altitude but return periodically to lower
levels in order to maintain the quality of training (2). Travel
Contemporary elite sport entails frequent travel, often over long durations
and distances. Indeed competing on a global basis and inter-continental
travel are lifestyle features of top performers. Major tournaments are
dispersed throughout the world so that the personal attraction of visiting
foreign countries is often tempered by the disruption and inconvenience
associated with the trip.
Recent Olympic Games have forced European athletes in particular to
consider their itineraries carefully. The summer Olympics of 1996 entailed
travel across multiple time-zones westward whereas the Sydney Games
required a greater displacement in an easterly direction. The Winter
Olympics in Nagano 1998 and Salt Lake City in 2002 also highlighted
the need for the European national teams to possess a travel strategy.
A similar situation prevails for European countries competing in Beijing
2008, or travelling to China beforehand for the purpose of a “dry
run”.
Travel strategies separate the hassle of travel and associated travel
fatigue from the desynchronisation of the body clock due to the mismatch
between the new local time and the body’s circadian rhythm. The
disruption is characterised by the syndrome of jet-lag (6). Whilst the
body clock is readjusting gradually to the new time zone, performance
can be affected. Pharmacological means of accelerating the adjustment
have proved to be less effective in athletes than have behavioural methods
(1). Exercise and training can play a role but lifestyle factors are
critical. Air Quality
A concern in urban areas is the quality of the air the inhabitants
breathe in. The level of pollution has been a consideration at Olympic
Games venues in the past, notably Mexico in 1968 and Los Angeles in
1984. Yet evidence of air quality affecting competitors is available
from the Summer Olympics 100 years ago.
The marathon course at St. Louis in 1904 was held over a rural road
surface. The runners were preceded by the new generation of motor cars,
scattered haphazardly amongst them (3). The clouds of dust generated
by the cars practically suffocated the runners moving in their wake.
Such lack of concern for the athletes was characteristic of sports spectacles
at this time.
Many teams visiting Athens before the 2004 Games have been able to
acquire their own data close to competitive venues for the concentration
of atmospheric pollutants. Athens is built on a basin, surrounded on
three sides by mountains and open to the sea. The topology and industry
in the basin and surrounding plains result in very high pollution levels.
The 90th percentile values shown in Table 1 demonstrate how Athens is
inferior to London for a range of environmental pollutants. These include
ozone, nitrogen dioxide, particulate matter less than 10 microns in
diameter (PM10s) and black smoke. The likelihood of vulnerable individuals
such as asthmatics being adversely affected in the environment of Athens
has been an issue with medical staff of competing teams.
The vagaries of climate place some sports at risk from the weather.
Swimming in open pools is halted in electrical storms. Wind conditions
may also prevent some sports being held or at least disrupt performance.
The Meltini wind funnels down from the Balkan mountains over Athens
when there is a thermal low over nearby Turkey. Sailors, triathlon swimmers
and rowers must learn how to deal with it, as must the archers. Overview
The global appeal of the Summer Olympics has never been more marked.
It is estimated that four billion people will have watched the Games
being transmitted on television. During the 16 days of competition,
the attention of the international media is focused on Athens and the
Olympic Games.
Individual environmental factors will be dealt with as they arise by
participants, prepared in advance with sports-specific support programmes.
In many cases, support staff as well as competitors are exposed to environmental
influences and must also be ready to cope. There are then more telling
questions to be addressed with respect to the context of the Games overall.
These embrace elements of legacy and economics, culture and philosophy,
materialism and ecology. In the changing milieu, it is appropriate to
consider again the relevance of the Olympic ideals to the contemporary
environment.
References
(1) Atkinson, G., Drust, B., Reilly, T. and Waterhouse, J. (2003).
The relevance of melatonin to sports medicine and science. Sports Medicine,
33, 809-831.
(2) Levine, B. (1995). Training and exercise at high altitudes. In:
Sport, Leisure and Ergonomics, pp. 74-92. London: E. and F.N. Spon.
(3) Martin, D.E. and Gynn, R.W.H. (2000). The Olympic Marathon: The
History and Drama of Sport’s Most Challenging Event. Champaign,
Ill: Human Kinetics.
(4) Peiser, B. and Reilly, T. (2004). Environmental factors in the
Summer Olympics in historical perspective. Journal of Sports Sciences,
22 (in press).
(5) Reilly, T. and Waterhouse, J. (2005). Sport, Exercise and Environmental
Physiology. Edinburgh: Elsevier.
(6) Waterhouse, J., Reilly, T. and Atkinson, G. (1997). Jet lag. Lancet,
350, 1611-1615.
Table 1. Winners of men’s event in track and
field: Mexico Olympics
![]() Table 2. A comparison of environmental pollutants
in Athens and London. Data presented are 90th percentile values in parts
per million.
![]()
Heat
Bengt Saltin The Copenhagen Muscle Research Centre University of Copenhagen Copenhagen Denmark
Abstract
Hot conditions impose strain on the cardiovascular system, which is
accentuated by dehydration. With reductions in cardiac output to the
active muscles, performance is adversely affected. Exhaustion seems
to occur at a common body temperature, implicating a thermoregulatory
limiting factor. Attention is shifted to mechanisms within the brain
that are associated with the exhausted state.
Key words
Dehydration, maximal oxygen uptake, pre-cooling, skin temperature
The basic issues
Intense exercise in the heat implicates three basic issues:-
Exercise for 120 min at 70-75% O2 max induces the
same skin temperature as exercise at 80-85% O2 max. Both muscle
temperature and core temperature are increased as a function of the higher
exercise intensity.
Skin temperature is influenced by the ambient air temperature rather
than by exercise. The rise in skin temperature is steeper for rest compared
with exercise as the air temperature increases.
The responses of skin and core temperatures for different
environments are shown in Table 1. At 40oC the normal gradient
from the body to the environment is reversed as the ambient temperature
exceeds body temperature.
The consequence of a high skin temperature when exercising
at 85-90% O2 max is that the difference between core and skin
temperatures decreases with elevations in ambient temperature. A gradient
of 7.5oC at 20oC is reduced to 5oC at
30oC, 2.5oC at 35oC and 0-0.5oC
at 40oC. Skin blood flow increases correspondingly from 3-4
l.min-1, 5-6 l.min-1, 7-8 l.min-1 and
maybe > 8 l.min-1.
The rise in core temperature is reduced during a
9-day period of acclimatization. The sweat rate is increased and at 35oC
the rate of sweat loss may approach 3 l.h-1.
Two questions follow:
The maximal fluid intake is in the range 1-1.5
l.h-1, slightly more in exceptional cases. This means a deficit
is likely to occur. This deficit increases the rate of rise in body temperature
and adds to the cardiovascular strain.
The bodily effects are complex and involve haemodynamics, fuel supply
to the active muscle and brain mechanisms. In many cases dehydration
is combined with heat stress so thermoregulatory limits to exercise
performance may prevail.
Effects on performance
A rise in body temperature will contribute to a reduction
in the level of performance and cause fatigue. A water-perfused jacket
can alter the rate of rise in body temperature from 0.10 to 0.05oC.min-1.
The rate of increase in body temperature is illustrated in Figure 1
for two different air temperatures (3). Performance of high-intensity
exercise was terminated earlier at the high temperature, the final muscle
temperature being similar for the two conditions.
Hyperthermia also causes a reduction in cardiac output. As oesophogeal
temperature increases, there is a corresponding increase in heart rate
and a reduction in stroke volume. Besides affecting cardiovascular haemodynamics,
hyperthermia and dehydration influence oxygen and fuel delivery to active
skeletal muscle and their utilization by active muscle.
The effects of dehydration were isolated in the study
of Gonzalez-Alonso et al. (1). The environmental conditions were 35oC
and 40% relative humidity. The power output of 210 W represented 60% O2
max. Two trials were compared:-
Cardiac output was maintained with euhydration, as was mean arterial
blood pressure (Figure 2a), in contrast to the falls occurring with
dehydration. The drop in cardiac output with dehydration affected the
distribution of blood to different tissues (Figure 2b). Blood flow to
the legs was reduced relative to euhydration, as were blood flow to
other tissues and forearm blood flow.
The decreased leg blood flow does not impair the
delivery of the required oxygen, glucose and FFA, or the removal of lactate.
Leg O2 , glucose uptake and FFA uptake are not drastically
altered. Skeletal muscle glycogen utilization, lactate production and
PCr degradation are elevated with dehydration (see Figure 3). Exhaustion
The exercise time to exhaustion seems to depend on the core temperature
reached. Observations on 10 subjects displayed a range from 40-70 min
for time to exhaustion. A feature of the data was that there was a common
core temperature around 40.5oC at the termination of exercise.
Brain temperature and metabolism may be linked with the process of
fatigue and eventual exhaustion (see Figure 4). Exercise hyperthermia
causes brain temperature to rise. Corresponding increases in a/ß
waves lead to decreases in arousal and voluntary activation (Figure
5). Perceived exertion is elevated and fatigue is promoted.
Brain oxygen extraction increases during high-intensity
exercise to fatigue. The a-vO2
difference reaches a similar level in hyperthermia compared to normal
conditions but fatigue occurs earlier (Figure 6). A similar pattern
is evident in oxygen extraction across exercising legs.
After exercise, there is an increase in brain O2.
Both a-vO2 difference and global brain O2 are elevated in heat
stress compared to normal conditions (Figure 7). In contrast to the exercising
legs, the brain possesses a large oxygen reserve at the point of exhaustion
which appears to secure the brain against reductions in systemic delivery
of oxygen (4).
Adjusting body temperature
Body temperature may be altered experimentally by
pre-cooling or pre-heating. Immersion in water at 18oC was
compared to responses to 37oC and 41oC. Air temperature
was 40oC and exercise at 240 W corresponded to 60% O2
max (3).
Exhaustion occurred at the same oesophogeal temperature and the same
muscle temperature in each condition. Mean skin temperature on termination
of exercise did not differ between conditions. Performance was reduced
in time by about 20 min with pre-heating and extended by about the same
time with pre-cooling (Figure 8).
Is fatigue due to insufficient skeletal muscle ATP production? Data
from Gonzalez-Alonso et al. (2) indicate that stores of PCr and ATP
are still adequate when fatigue occurs with dehydration (see Figure
9).
Muscle, oesophogeal and femoral blood temperatures stabilize during
sustained exercise or show a small increase when subjects are euhydrated.
This trend contrasts with dehydration, where all these temperatures
continue to increase. Hyperthermia, whether subjects are euhydrated
or dehydrated, induces the highest oesophogeal and skin temperatures
(5). Performance is extended when dehydrated if ambient temperature
is normal, and prolonged further in euhydration-normal compared to exercising
in heat (see Figure 10).
Heart rate is increased with hyperthermia, whether
euhydrated or dehydrated. There is a corresponding reduction in oxygen
uptake at maximal exercise. Heat stress clearly impairs O2 max
and has consequences for performance. These findings support the view
that fatigue during maximal exercise is largely associated with the failure
of the heart to maintain cardiac output and the delivery of oxygen to
the skeletal muscle. References
Table 1. Responses of skin and core temperature for different environments.
Values are in o C
![]() Figure 1. Rate of increase in body temperature for different
air temperatures.
![]()
Figure 2. Cardiac output, mean arterial pressure (2a) and blood distribution
(2b) during euhydration and dehydration.
![]()
Figure 3. Muscle glycogen utilization and lactate production due to
dehydration.
![]() Figure 4. Brain temperature at exhaustion.
![]() Figure 5. Schematic model of fatigue during
exercise in the heat.
![]() Figure 6. Arterio-venous oxygen difference
across the brain in dehydration.
![]() Figure 7. Global brain oxygen uptake during
dehydration.
![]() Figure 8. Effects of pre-cooling and pre-heating
on exercise performance.
![]() Figure 9. Stores of PCr and ATP at the point
of fatigue during dehydration.
![]() Figure 10. Performance during exercise in
the heat.
![]() The Use of Altitude Training – Possible Reasons for
Benefit and Failures
Ulrich Hartmann Technical University of Munich Faculty of Sport Science Department for Theory and Practice in Sport Munich Germany
Abstract
Training at moderate high altitude (HA; 1800 to 2400 m) is one of the
few possibilities available to increase the performance more than by
the normally given circumstances. To estimate the positive (or negative)
effects of training at HA, personal experiences from the point of view
of a direct monitoring of training play an important role. Besides the
general difficulties of estimating the (positive/negative) effect of
training at HA, only few objective data from training practice with
top class athletes are available. The effect of training at HA with
the goal to improve performance capacity in endurance sports is still
under discussion in the sports sciences [2, 3].
In discussing positive or negative effects of high altitude, we have
to separate out: 1. General effects of adaptation during or after exposure
to high altitude, which give an unspecific benefit. 2. Positive (or
negative) training effects which can be similar during training at high
altitude or at sea level; additional to this outcome, the training at
high altitude can be influenced in a positive (or negative) way. 3.
Effects and benefits of training which can be caused only by a stay
under high altitude conditions. In most of the studies no differentiation
has been made between these aspects, which makes it difficult to interpret
under isolated points of view the benefits and / or failures of a stay
under HA conditions. Besides these facts, there is the problem of interpreting
those effects of a continuous stay versus a regular intermittent hypoxic
exposure (LH – TL: Live high, train low; LL – TH; live low,
train high) or even more so the effects of several new altitude training
strategies like a) normobaric hypoxia via nitrogen dilution (nitrogen
apartment), b) supplemental oxygen, c) hypoxic sleeping devices, and
d) short-term intermittent hypoxic exposure.
Under general aspects, it should be helpful to outline the benefits
of a permanent stay at HA under the aspects of an individual positive-responding
athlete. According to these results, an increase of the total blood
volume (BV) and a higher capacity for the transport of oxygen can be
anticipated [1, 4, 5, 6]. The consequences of this effect can be interpreted
by means of an approximation equation. Besides that, the maturation
of the reticulocytes (RET) and their increase show a great individual
variability (between 10% and 250%); the intra-individual variation in
a later study (40% compared to 150% in one athlete) has probably a great
influence for the individual increase in BV. The increase in BV is the
basis for a positive development of performance during and after a training
period at HA.
Therefore a calculation can be provided, focusing on the resulting
effect of a higher transportation capacity which is caused by an increase
of red blood cells in combination with a higher BV. As long as those
effects are generating a systematic benefit in athletes responding positively
(e.g. in many members of an elite rowing team) this seems to be at least
an indication of a positive aspect of a prolonged or permanent stay
at HA. For an intermittent stay or for the other new altitude training
strategies (see above), consistent evidence cannot be shown as regular
effects in top athletes.
Another influencing and probably the most important factor with regard
to the benefit of a stay under hypoxic conditions is the stress presented
to the muscle cell, possibly yielding a misleading adaptation of the
muscle cell by an (inadequate) load of the training content. Therefore
it should be necessary to focus more on individual aspects of the average
volume and intensity in the total amount of training of athletes in
middle-distance sport events [2]. Referring to our own findings, the
intensities during a HA-training camp were significantly different.
In particular, a medium to high intensive training (“speed training”)
often did not lead to the anticipated long-term training effect or decreased
the power output over a given period of time. Although dominant and
solely not a specific problem under HA conditions, it seems to be one
of the general problems of muscular mal-adaptation which can be negatively
fortified under HA conditions, theoretically independent of which altitude
training strategies have been chosen. It includes consideration of the
actual subjective perceptions and their biological influences on the
sport practitioner and incorporation of the traditional points of view
(e.g. for periodization). References
[1]. Ekblom et al. (1972): J. Appl. Physiol. 33, 175-180
[2]. Hartmann & Mader (1999): In: Zeitschrift für Angewandte
Trainingswissenschaft (ed), 6, 1, 72–105
[3]. Levine & Stray-Gunderson (1997): J. Appl. Physiol. 83, 102-112
[4]. Luft U. (1941): Ergebn. Physiol. 44, 256-312
[5]. Rost et al. (1975): Sportarzt und Sportmedizin 26, 137-144
[6]. Williams at al. (1973): Med. and Science in Sports 5, 181-186
The lifestyle of current elite athletes: coping with jet lag
Benjamin J Edwards Research Institute for Sport and Exercise Sciences Liverpool John Moores University Henry Cotton Building 15-21 Webster St Liverpool L2 3ET UK
Abstract
International travel is an essential part of the lives of elite athletes,
both for purposes of competition and training. Long-haul flights entail
crossing multiple time zones, and this causes jet lag, due to disruption
of the normal circadian rhythm. Various pharmacological and behavioural
approaches have been used to reduce some of the effects of jet lag in
sports performers. This overview focuses on strategies used for the
Sydney summer Olympics 2000 (10 time zones to the east from the UK),
and looks forward to the Beijing 2008 Olympics (8 time zones to the
east from the UK). Travel fatigue lasts for only a day or so, is associated
with the conditions of the journey (such as the cramped nature of the
seating), anxiety about travel, and disruption to the individual’s
daily routine and can be separated from the jet lag phenomenon. For
those who fly across multiple time zones the effects associated with
jet lag are longer lasting, and can reduce motivation to train effectively
and impact negatively on performance. The severity and duration of these
problems depend on the direction of flight (eastwards or westwards),
the number of time zones crossed, and the strategies used to alleviate
them. Behavioural solutions for dealing with jet lag involve attention
to lifestyle and activity. These methods are preferable to pharmacological
means of treating the syndrome. There remains the issue of athlete compliance
with any travel strategies, and a systematic educational programme can
assist in securing acceptance of any recommendations.
Key words: Behaviour, pharmacology,
promoting readjustment, time-zone transitions.
Introduction
Circadian rhythmicity in human physiology has been extensively reported.
The internal timing mechanism that mediates this rhythm (the body clock)
is located within the anterior of the hypothalamus in the suprachiasmatic
nucleus (SCN). The purpose of circadian rhythms is to prepare the body
for waking in the light and for sleeping when it is naturally dark.
Temporal isolation studies, wherein subjects are kept in caves or isolation
chambers and in conditions of a constant environment, have shown that
one of the inherent characteristics of the body clock is that it free-runs
with a period of ~24.5 hours, so it tends to become phase delayed. This
inexact timing mechanism is set to an exact 24-hour day by so-called
zeitgebers (time givers); these include the light-dark cycle, the sleep-wake
cycle, rhythms in socialisation, feeding and, possibly, based on some
recent evidence, rhythms of activity and exercise.
Jet lag is caused by the sluggish readjustment of the circadian timing
mechanism to the new environment. Table 1 illustrates this adjustment
for a flight from the UK to Beijing, China (8 time zones eastwards).
Other explanations for jet lag include 1) the hassle of the flight,
2) the new lifestyle, food and culture at the destination, 3) the excitement
of attending important events, and 4) the length of the flight. However,
jet lag can be induced in an isolation chamber (where no travel has
been undertaken), is found after returning home back to a normal routine,
and its severity is related to the number of time zones crossed, not
the flight length. The symptoms of jet lag include the following: fatigue;
sleep disturbance (either the inability to get to sleep or an earlier
waking time); inappropriately timed hunger or loss of appetite; losses
of concentration and drive; and headaches. The net result is a likely
decrease in training effect and performance.
How long does it take to get over jet lag?
Unlike travel fatigue, which an individual normally takes less
than 24 hours to recover from, recovery from jet lag depends on the
direction of travel and the number of time zones crossed. Generally,
symptoms are more severe and readjustment takes longer the greater the
number of time zones involved. Eastward travel is less well tolerated
than westward, due to the inherent property of the body clock to run
slightly slow. Further, after an eastward journey across 10 time zones,
current guidelines suggest that, for the purposes of the use of light
as a readjustment strategy, it should be treated as a transition of
14 hours to the west. This tendency for the body clock to adjust by
a delay rather than an advance after crossing 10-12 time zones in an
easterly direction (where destination time is advanced by 10-12 hours
with regard to departure time) is termed an antidromic effect.
There is some evidence that older individuals, who are generally less
fit, take longer to readjust than younger, fitter individuals (9). This
superiority is not necessarily the case in well-motivated and experienced
travellers (10).
![]() The problems of jet lag can be reduced and managed by suitable planning
before the flight, actions during it, and after arrival at the destination.
Many Olympic squads are given formal advice, normally in the form of
a booklet as a complement to personal counselling. In the case of the
Great Britain Olympic team (Team GB), this advice was the culmination
of two years research, in which a “dry run” was conducted
the year before the 2000 Games, and each athlete who participated received
a feedback report on his/her adjustment. This targeting and specific
educational programme prior to the Games led to a good compliance of
staff and athletes at the preparation camp in the Gold Coast (Australia),
and identified those individuals who had severe symptoms and a slower
than average rate of adjustment. Before the flight
For complete adaptation, current advice suggests that athletes should
schedule their arrival well in advance of competition, allowing one
day for each time zone travelled to the west and 1.5 days for each time-zone
travelled in an easterly direction (4). This allowance may be an overestimation
and would be impractical, as it would require an athlete travelling
from the UK to arrive 15 days prior to the 2000 Games. The athletes
spend longer than this period at the “preparation camp”.
It has prompted a more realistic suggestion of leaving one day for each
time zone crossed in either westward or eastward journeys (9). Travel times
Some of the factors that can be changed relatively easily are the time
of flight departure, and hence time of arrival, and the decision whether
or not to incorporate a stopover to break up the journey. Arriving as
close to night-time in the new time zone as schedules allow promotes
adjustment indirectly due to the accumulation of fatigue during the
flight; this tactic aids sleep during the first night-time at the destination,
and the sleep-wake cycle acts as a zeitgeber. If the journey (such as
one from the UK to the East coast of Australia) is broken up, with a
stopover in Singapore for a few days, this break aids adjustment at
the final destination, as it gives the body clock a chance to adjust
partially when exposed to the environment at the place of stopover.
In practice, this break in the journey involves extra hassle for the
athlete in terms of maintaining quality of training. Also, it could
add complications such as heat and humidity in the stopover environment,
and these present their own problems for the athlete. Pre-adjustment strategy
Generally, adjustment of sleep-wake habits prior to the flight could
in theory begin to alter the normal circadian rhythm in the desired
direction prior to departure. This strategy involves sending the athlete
to bed earlier and getting him/her up earlier for an eastward journey,
and to retire and rise later for a westward journey. The strategy for
a westward flight is tolerated more easily than that for a flight to
the east as, when sent to bed earlier (eastward flight), athletes find
it hard to get to sleep until the normal time (biological time) - and
then are expected to wake earlier than usual. As a result, some sleep
deprivation occurs. In order to avoid disrupting the circadian rhythm
unduly and allow the athlete to continue to train normally, an adjustment
of the sleep-wake cycle by no more than 1-2 hours and for no more than
1-2 days is recommended. During the flight
Generally, when onboard the idea is to change as much as possible the
behaviour of the athlete to that appropriate to destination time in
terms of activity, sleep and wakefulness, and eating meals. These strategies
should be conveyed to the cabin crew, to avoid confusion and inappropriate
times of waking the athlete, for example for meals. Further, there is
a need to replenish the fluid loss due to the dry environment on the
plane. Diuretics such as those containing caffeine or alcohol should
be avoided during the flight, as they are diuretics and would accentuate
dehydration. Due to the increase in incidence of deep vein thrombosis
associated with inactivity in a cramped environment, performing isometric
exercises, and leaving the seat periodically to walk around the plane,
are advised. After arrival
There has recently been some interest in the use of massage and deep
breathing. Neither of these strategies has been shown to aid adjustment
at the destination, though the value of massage to stimulate blood flow
after travel is not to be discouraged. The two general approaches to
readjustment are pharmacological and behavioural. The use of chronobiotics
such as melatonin, which directly shifts the body clock or indirectly
aids adjustment due to the hypnotic properties that aid getting to sleep
at the new night-time, has received some attention in research on jet
lag. There has been some concern with appropriate timing of melatonin
to aid in readjustment after an easterly transition across 10 time zones.
Further, when strict control of light-avoidance and exposure is not
adhered to, the effectiveness of melatonin is reduced (1). The current
position statement of the British Olympic Association advises athletes
against using melatonin. Furthermore, in the UK, pure melatonin is available
only when prescribed by a physician (8).
The behavioural strategy involves the appropriate use of the zeitgebers
(time-givers) that aid entrainment – the light-dark and the sleep-wakefulness
cycles, diet and meal-times, and activity and exercise. There is little
scientific evidence to support the value of diet in promoting clock
adjustment, the suggestion being to consume protein in the morning and
carbohydrate at night-time, in order to promote arousal and sleep, respectively.
In implementing adjustment strategies aimed at shifting the human circadian
rhythm, an indirect marker for the body clock is used. This reference
point is the body temperature minimum. Rectal temperature shows its
peak value at ~18:00 hours and a minimum at 06:00 hours, and this 24-hour
profile can be described well by a cosine curve (see Figure 1). Light
is the strongest zeitgeber, and the effect of light depends upon the
time of exposure, as described by a phase-response curve (2, 3, 5).
Exposure to light during the 6 hours before the temperature minimum
results in a delay, and in the 6 hours after the temperature minimum
a phase advance. Exposure to bright light at other times results in
no phase shift, and this is referred to as a “dead-zone”.
If a phase-delaying strategy is used, in the case of a 10 time-zone
transition to the east (UK to the east coast of Australia), this would
mean exposure to light between 10:00-16:00 hours (local time) on day
1 and avoiding light between 16:00-22:00 hours. On day 2, as the body
temperature minimum would have delayed by about one hour to 17:00 h
by local time), the next day’s light exposure would be between
11:00-17:00 hours and avoidance between 17:00-23:00 hours, and so on
for subsequent days. If a phase-advance strategy were used for the same
journey, then light would be avoided before 16:00 hours for the 2-3
days in the new time-zone. It is generally found that readjustment tends
to follow an exponential function, with greater adjustment occurring
in the first few days (12).
![]() ![]() Figure 2 shows the working example of a possible advantage of adjustment
by a phase delay (14 hours) rather than advance after a time-zone transition
of 10 hours. Peak performance generally occurs in the evening and the
temperature minimum, associated with greater sleepiness and lowest performance,
is found towards the end of sleep. The cosine curve has been transposed
onto the local time in the new time-zone, with complete adjustment shown.
Immediately after arrival, peak temperature and performance will be
at about 04:00 hours and the minimum temperature value and worst performance
at 16:00 hours. If a phase delay occurs, peak performance is delayed
through the day such that it occurs later each day and sleepiness prevails
through the evening. This adaptation means that there is some time of
the day when high-quality training can take place during the process
of adjustment. By contrast, an advance of the body clock by 10 hours
moves the peaks of temperature and performance through the night-time
in the new time–zone, and the temperature minimum and maximum
sleepiness occur in the morning and afternoon. This timing indicates
a theoretical advantage with adjustment by a delay rather than an advance
after an eastward journey across 10 time zones. It also is more convenient
with regard to light exposure for individuals arriving in the early
morning in the new time-zone. There are, however, difficulties in translating
theory to practice. In the field study before the Sydney Olympics, referred
to above, adjustment was consistent with a delay for 35/85 individuals,
with that of an advance of the body clock for 23/85 and for 27/85 it
was unclear as to whether adjustment was by an advance or delay (7,
11). Such a separation of adjustment would have made it difficult to
manage daily preparations in Australia after arrival. Therefore, with
the additional consideration of departure and arrival times and keeping
the teams as a whole entity, a ‘phase-advance’ strategy
was chosen for all, involving light-avoidance in the morning, no morning
training for 3-4 days, and a lie-in in bed for the first three days.
This strategy worked well prior to the 2000 Summer Olympics. Issues relating to athletes and jet lag coping strategies
Those athletes who were the more compliant tended to adjust faster
than those who were resistant; the “poor adjusters” tended
to be led by coaches and managers who were resistant to the advice,
but rather stuck to “what they always did”, irrespective
of the multiple time-zone transition. Training at a lower intensity
and duration than normal for the first couple of days after arrival
was advocated, to help reduce possible problems with injury. Exercise
can take place outdoors at times advocated for light exposure, and tactics
might be discussed indoors when light should be avoided. One of the
problems at the destination is “anchor sleep” which refers
to a short sleep period at the time the individual would normally have
been asleep if living on home time. Such sleep contrives to “anchor”
circadian rhythms to home time and this opposes adaptation to the new
local time. For this reason, napping is not advocated for the first
few days after arrival at the destination. On restarting normal training
practices, the coach should monitor the athletes whilst they are not
fully adjusted, and everybody’s expectations of performance should
reflect this lack of full adjustment. When educating the athlete as
to what jet lag is and what strategies should be adopted to minimise
it, the encouragement of perseverance, compliance and a positive attitude
helps to promote adjustment to the new time zone. Conclusions: Looking forward to the Beijing 2008 summer Games
Essential planning and preparation include a comprehensive programme
that starts prior to travel and includes coping strategies that apply
both onboard and after arrival. The first question regarding UK and
European athletes travelling to Beijing is ‘should they attempt
to advance the body clock by 8 hours or delay it by 16 hours?’
Unlike the Sydney Games, where a delay of 14 hours was at least feasible,
an 8-hour advance (for the Beijing Games) would be easier to achieve
than a 16-h delay; behaviour to promote such an advance should be advocated.
The behavioural approach of light exposure and avoidance, coupled with
outdoor exercise and indoor discussions when appropriate, will be paramount
in achieving this aim. The strategy can be implemented by raising awareness
of the issues involved, and by providing clear guidelines on the actions
required and the behaviour patterns to be avoided. The use of drugs
such as hypnotics or melatonin is not advocated – although those
athletes that already do use these means will not be advised against
continuing to do so, but they should be monitored by their sports physician.
Further, it is good practice to send key athletic support staff to the
destination before the athletes’ arrival, to ensure they are prepared
for the athletes and not getting over jet lag themselves when they have
to be fully alert for work.
Key points:
References
List of tables and figures
Table 1. Mismatch between local time and body clock time (hour) after
a flight from the UK to Beijing (8 time-zones to the east).
Figure 1. The cosine curve for rectal temperature over a 24-hour period,
with an example of the strategy for light exposure and avoidance after
a easterly transition of 10 time-zones.
Figure 2. Schematic representation of advancing 10 hours or adjustment
by a 14-hour delay of the circadian rhythm of rectal temperature after
an easterly flight across 10 time-zones. Shading indicates nighttime.
Table 1. Mismatch between local time and body clock time (hour) after
a flight from the UK to Beijing (8 time-zones to the east).
Olympic Sport and the Ecological Ideal of a
Sustainable Development Sigmund Loland The Norwegian University for Sport and Physical Education Norway
Abstract
The question discussed here is whether Olympic sport can be said to
meet the ecological ideal of a sustainable development. The question
can be understood in several ways. Some analyses focus on ecological
costs in terms of the use of non-renewable natural resources, and pollution.
A less common perspective deals with the nature of Olympic competition
itself and its requirements on human resources. This latter perspective
will be pursued here. The approach is analytic and casuistic. Firstly,
the ideal of a sustainable development is defined and operationalized.
Secondly, representative cases from Olympic sport are examined as to
whether the requirements on human resources support this ideal or not.
The ideal of a sustainable development is defined as a development that
meets the needs of the present without compromising the ability of future
generations to meet their own needs. A narrow interpretation of the
Olympic sport and its motto citius, altius, fortius points towards continuous,
quantitative growth of performance. This interpretation is seen to contradict
the ideal of a sustainable development. A wide interpretation of Olympic
sport opens for human complexity and diversity and qualitative measures
of performance. Such an interpretation is seen to be ecologically sound.
Olympic sport and its ideals are ambiguous. A narrow interpretation
expresses an ecologically unsound quest for unlimited growth in limited
systems. A wide interpretation opens for an ecologically sound exploration
of human complexity and diversity in open systems. In conclusion, some
critical comments are given on the possible role and consequences of
the wide interpretation in future Olympic sport.
Key terms: Coubertin, performance,
records, sustainability.
Introduction
In the so-called fundamental principles of the Olympic
Movement, one key reference is the development of human kind through a
blend of sport, culture, and education. In the mid-1990s, and due to an
increasing awareness of global ecological challenges, the International
Olympic Committee (IOC) included the environment as an additional dimension.
The IOC’s Sport and Environment Commission emphasizes the responsibility
for promoting sustainable development in particular ( For more information
see http://olympic.org/UK/organisation/commissions/environment/games-uk.asp).
The operational outcome of this engagement is a set of requirements
to be met by Olympic organizers in terms of plans for the environment
and for waste and energy management. Although such measures are of value,
they do not really matter much if the basic Olympic message is non-ecological
in kind. The eco-philosopher Arne Næss (5) pointed towards the
significance of what he calls deep ecological thinking in which the
basic principles and values guiding and justifying our practices are
critically examined. My perspective here will be a deep ecological one.
My focus will be on what can be seen as the core of Olympic events,
Olympic sports. My question will be whether ecological ideals are compatible
with the values of Olympic sports, or whether there value conflicts
here which are difficult to overcome. Ecological ideals
Ecological ideals can be of many kinds. A basic distinction can be
drawn between anthropocentric and non-anthropocentric perspectives.
From the non-anthropocentric perspective, all life forms, or even landscapes,
can be given moral status independent of their value to human beings.
Non-anthropological theories challenge in fundamental ways conventional
ideas about our relationship to nature, and they have radical implications
for sport (2). It will lead too far to pursue this line of reasoning
here. Anthropocentric theories on the other hand, in which the value
of nature depends upon its role in the contribution to human well-being,
are more conventional, and these are the perspectives to which IOC subscribes.
A core anthropocentric ideal, endorsed by the UN World Commission on
Environment and Development (7) and by the IOC, is the ideal of a sustainable
development. A sustainable development is defined as a development that
meets the requirements of the present without compromising the possibilities
of future generations to meet their own needs. Further elaboration points
towards the dangers of specialized mono-cultures and to the significance
of biological and cultural diversity and complexity. The ideal has been
discussed in fields such biology, economy, technology, politics and
culture. The question here is whether Olympic sports can be said to
conform to the ideal. Sustainable Development and Olympic Sports
According to the Olympic Charter, Coubertin’s
ideology of Olympism is still the defining ideology of the Movement (http://www.olympic.org.uk/utilities/reports/level2_uk.asp?HEAD2=26&HEAD1=10).
Coubertin’s extensive writings are not always clear and sometimes
even contradictory. However, inspired by colleagues and friends, Coubertin
succeeded in formulated a striking ‘slogan’ that has become
the official Olympic motto: citius, altius, fortius (faster,
higher and stronger). According to Coubertin, the setting of records has
the same function in Olympic ideology as the law of gravity in Newtonian
mechanics – it is ‘the eternal axiom’. The motto emphasizes
the highly competitive performance orientation of elite sports, and it
reflects the cult of objective, quantitative progress that characterizes
the Western culture of modernity in which the Olympic Movement has found
its form (1,6). From an ecological perspective, the continuous quest for
improved performances and records has some deeply problematic implications.
Elsewhere I have discussed in more detail problems linked to high degree
of specialization in sport performances (4). Here comes a brief sketch
of the argument. A specialized performance is a performance based primarily
on one or two basic bio-motor abilities (such as speed, strength, and
endurance), and in which sport-specific technical and tactical skills
play minor roles. Most record sports provide paradigmatic cases in this
respect. What is at stake here is objective and standardized performance
measurements in which the crucial parameters are those of speed, strength,
or endurance. Take as an example a typical record sport, the 100-metre
sprint race. Biologically, human capabilities for speed are limited.
Although new records can be set again and again, every new record represents
a further step in the utilization of this limited capability. The continuous
quest for improved performance stimulates the development of more or
less extreme performance-enhancing means and methods. Some of these,
such as doping, have significant moral costs. As soon as a new record
is set, the challenge for other runners, or for the next generation
of runners, becomes greater. “Record sports” build on the
impossible quest for unlimited growth in highly specialized limited
systems. In this sense, they seem to represent non-sustainable systems
and appear as biological and moral risk zones.
Other sports are defined by less specialized and more complex and diverse
performance requirements. In ball games, for example, performances are
built on technical and tactical skills, they are measured in non-exact
entities such as points and goals, and they are always relative to an
opposition (Figure 1). Although discussions of who is the best player
or what is the best game ever are interesting and entertaining, there
are no precise and agreed criteria upon which they can be settled. Games
offer no possibility for record setting in the strict sense of the term.
Every new contest is a new opportunity, and one great performance does
not represent a utilization of resources that are not available to other
players or new generations of players. Obviously, sports with more complex
performance ideals constitute sustainable systems to a larger extent,
and they are less vulnerable to excessive and morally problematic performance-enhancing
means and methods. From the ecological perspective, they are sounder. Concluding Comments
I have sketched an answer to the question of whether Olympic sports
can be said to conform to the ideal of a sustainable development. The
answer is both in the positive and the negative. I have argued that
the Olympic ideal of highly specialized record sports performances is
a non-sustainable one, and that games offer a more sustainable sport
paradigm. The argument calls for some concluding comments
If the points above are valid, one should expect that specialized record
sports will degenerate and vanish. Indeed, the degeneration scenario
is possible. However, it is not the only one. Without being able to
go into details at this point, I have pointed out elsewhere how record
sports can be restructured into more complex, diverse and sustainable
performance systems (3) and I believe that these are constructive alternatives
worth considering here.
Another possibility is that the problem of non-sustainability is met
by emerging, alternative sport paradigms such as those found in the
increasingly popular board sports (such as surfing, skate boarding,
snow boarding, and kite boarding). These activities build on non-quantifiable,
creative performances with emphasis on individual expression and artistic
values. As with games, they are less vulnerable to bio-medical performance-enhancing
excesses than traditional record sports, and they might constitute a
more sustainable Olympic sport paradigm in the time to come. References
Figure 1. The game of hurling engages technical and tactical skills,
scoring is by goals (equal to 3 points) and points.
Characteristics:
![]() Contact:
Thomas Reilly Research Institute for Sport and Exercise Sciences Liverpool John Moores University Henry Cotton Campus 15-21 Webster Street Liverpool, L3 2ET United Kingdom T.P.Reilly@ljmu.ac.uk ![]() http://www.icsspe.org/portal/index.php?w=1&z=5 |