by Chelsea R. Warr, B.Sp.Sc;Grad. Dip. Phy. Ed
Department of Physiology and Applied Nutrition, Australian Institute of Sport
International sports competition is inevitably linked to overseas travel. With Australia being so globally isolated from prominent sporting events often occurring in the northern hemisphere, our athletes are undertaking extended flights and expected to compete optimally days later. Furthermore, many Australian athletes are travelling more frequently for exposure to environmental stressors such as heat and altitude in the attempt to enhance performance. The repercussions of extended flights are a general nuisance to the tourist traveller. For the elite athlete, rapid time zone travel undoubtedly impairs their potential in competition and in some instances can severely compromise performance.
Coaches commonly report noticeable decreases in various components of athletic performance between days 2-4 following extended flights. Performance gradually returns to normal by day 6 for most individuals (Lawrence 1993). Scientists suggest that this decrement in performance is caused by the dysynchronization of circadianrhythms (Your Biological Clock, Hill 1993, Shephard 1989, Reilly 1984, Winget 1988). More commonly, athletes and coaches attribute their poor performance to “jetlag.”
Although jetlag is inevitable with transmeridian flying, following simple procedures can help to prevent and alleviate many symptoms that can affect athletic performance. Furthermore, these procedures also hasten the resynchronization phase upon arrival, allowing the athlete to adjust to local time and complete usual training loads. The following is an outline of practical strategies implemented by Australian Institute of Sport (AIS) coaches, athletes and sports science/medicine staff when travelling overseas.
It is well documented that rapid time zone travel causes circadian dysrhythmia (jetlag). Jetlag occurs when there is a mismatch between the external zeitgebers (environmental time givers such as light and social interaction) and the internal body clock of an individual. More simply, the body’s internal clock becomes confused between the place of departure and place of arrival. This confusion is often characterized by malaise and a host of other symptoms including loss of appetite, tiredness and disturbed sleep, all of which contribute to poor athletic performance (O’Conner 1990).
Body arousal levels, temperature, strength and flexibility fluctuate over a 24 hour period. They peak in the late afternoon or early evening and are at a minimum by early morning. Consequently it may be expected that peak sports performance will coincide with peak levels of these parameters, i.e. in the late afternoon or early evening (Eichner 1988, Shephard 1984, Hill 1993). Literature cites many other examples of improved performance later in the day.
When athletes travel across time zones their normal 24 hour cycle of peaks and troughs in body arousal levels, temperature, strength and flexibility will no longer correspond with the day/night cycle of the destination. That is, their internal body clock is out of synch with the true time. For example, a 3 pm competition schedule in the new destination may equate to 3 am (sleeping time) in the previous one. How can the body work optimally when presented with such a scenario?
In knowing that international air travel can disturb the precise timing of various hormonal and physiological rhythms, it is prudent for coaches and athletes to:
- Implement preflight jetlag programs.
- Undertake in-flight anti-jetlag procedures.
- Use strategies to hasten resynchronization of the internal clock after arrival.
- Modify initial training sessions during the adjustment phase.
What Affects the Severity of Jetlag?
Understanding the variables that affect the severity of jetlag can help coaches program sufficient recovery time while travelling on tour. Naturally, not all athletes will be affected in the same way, or to the same degree, but there is a distinct possibility that some disruption will occur.
Number of times zones crossed.
The severity of jetlag is proportional to the number of time zones crossed. A rule of thumb calculation would allow about one day recovery for each hour of the clock shifted going west but slightly less for an east bound flight (Jones 1995). Coaches should assess the degree of disturbance by the direction of travel chosen and where possible plan to minimize the amount of time zones crossed altogether.
Direction of flight.
Westward flights, in which the body clock is delayed, appear to require a shorter recovery time than east bound flights where an advancement to the body clock occurs. Time shifts of up to six hours appear more tolerable than longer travel periods. Coaches should plan to break up considerably longer journeys for faster recovery.
The dry atmosphere in an aircraft cabin can cause a travelling athlete to become dehydrated (Bond 1988). Hydration status is further compromised by athletes spending time in air-conditioned hotel rooms and airports. Dehydration often contributes to many of the common symptoms of jetlag such as headache, malaise and disorientation.
Those who engage in social interaction following arrival seem to adapt significantly faster those who remain socially isolated (Loat et al 1989). Social interaction is considered to be a strong zeitgeber for circadian re-entrainment, therefore suggesting that an extrovert copes better with jetlag than an introvert.
Although sleeping agents do not directly resynchronize circadian rhythms, they may relieve insomnia, a common symptom of jetlag.
Jetlag minimization programs and travel experience.
Circadian dysrhythmia is inevitable with rapid time zone travel, however anti-lag programs can minimize the acute symptoms an athlete may experience (Lawrence 1993). Those who are more experienced at travelling adapt more quickly than novices.
Guidelines for Travelling Athletes and Coaches
Pre-planning and organization is the key to a successful trip and will minimize athletes becoming distracted from the task at hand.
- Pre-book aisle or exit row seating to allow more room to stretch especially when travelling with teams of taller athletes (e.g. basketballers).
- Special meals on most major airlines can be easily arranged with as little notice as 36 hours prior to departure. Examples include low fat and vegetarian. Some airlines even provide athlete meals for group bookings (e.g. low fat, high carbohydrate). Avoid overeating. Remember that you are sedentary, perhaps even tapering, hence your caloric intake will not be high.
- To avoid transit hunger, pack healthy snacks which need minimum storage fuss and are long lasting (e.g. fruits, dried crackers, sport energy bars, liquid meals).
- AIS physicians suggest that pharmaceutical intervention to combat sleep difficulties during long haul flights should be based on individual preferences. Should athletes choose to use prescribed sleeping agents, trial at least one week before departing to observe potential side effects.
- Providing players with cultural profiles of the particular countries to be visited allows them to become familiar with local customs, foods, weather etc.
- Make contact with the proposed accommodation to determine when sporting facilities are available for guests.
During the Flight:
Maintaining Hydration – The oxygen concentration and humidity of aircraft cabins are considerably lower than normal air. This dry environment can cause athletes to lose more than 300ml of water per hour depending on their body size, with larger athletes losing significantly more.
- Drink at least 300ml of fluid, preferably water every hour, to remain well-hydrated. This equates to 1.5 standard cups per hour (approximately 10 small airline cups!).
- Pack water bottles or sport drinks with you and have them seated in the front pocket as a reminder to drink frequently and stay well-hydrated.
- Avoid coffee, tea, carbonated drinks and alcohol which are offered during the flight. Many of these act as diuretics and can contribute to further dehydration.
- Wet towels and water sprays can help to avoid dryness developing in the nose and throat.
- Avoid overeating as inactivity on the plane means that you actually require a smaller caloric intake than required for a normal training day.
- Adjusting your meal times to those of the country you are heading to can prompt the resynchronization process.
- In-flight stretching programs discreetly done from your seat can aid “travellers thrombosis” (e.g. pins and needles, swelling). Moving around the plane from time to time is also helpful.
- Transit stops are also a good opportunity to do some light exercise.
- Adjust your watch to the destination time when boarding the plane and try to synchronize daily routines accordingly. In-house entertainment and blackout eye pads may help.
Diet, exercise, sunlight and social interaction are the key environmental cues (zeitgebers) to allow resynchronization.
- Stay awake even if you are tired. Unpacking luggage, stretching and light exercise (e.g. swimming) are favorable options.
- Social interaction and natural sunlight is an excellent re-entrainment tool so go outdoors and do a little socializing!
- Where possible, schedule un-taxing introductory matches and training.
- Initial training sessions need to be easy to moderate and carefully monitored by the coaching staff.
- Avoid taking sedatives as they delay the natural adjustment process.
Training Recommendations Following Travel.
Lawrence and colleagues (1993) from the Western Australian Institute of Sport reported a significant reduction in 20 meter sprint performance and reaction time on day 34 of arrival in female national hockey team representatives.
A concurrent deterioration in coordination and technical aspects of performance was also noted by the head coach. Performance gradually returned to pre-departure levels by around day 7. Practical recommendations. The following recommendations are based on the outcomes of this and similar studies.
- Initial training sessions should be light to allow the body to recover from the flight experience. Exercise modalities should focus on flexibility and promote movement through the full joint range available (e.g. swimming).
- During early days of arrival encourage all team members to implement additional therapeutic forms of recovery into their programs. Hydrotherapies (e.g. contrasting temperature showers and spas), restorative massage and mental relaxation techniques are therapies promoted by AIS recovery specialists.
- Skills and technique often deteriorate during the adjustment phase. Coaches should work on basics to avoid frustration developing among players during the first few training sessions.
- Morning sessions should focus on more detailed instructions such as combination work and tactical plays. Afternoon sessions should include basic drills and recovery work.
- Encourage athletes to keep tour diaries, providing psychological and physiological feedback for the coach on how the athlete is adapting.
- Coaches may revert to the standard program around days 4-6.
It is apparent that no one program will satisfy all athletes travelling hence the coach will need to assess each individual’s progress in preparation for early competitions. Standard selection criteria to compete must be flexible. This often means allowing players who are lacking form during initial sessions to compete, in order to maintain their morale for events scheduled later.
Various new products are presently on the market which claim to alleviate dehydration and dysrhythmia caused by aircraft travel. Although these have not been scientifically proven to enhance athletic performance, many current AIS sports use these products in order to alleviate symptoms they report hamper their performance.
The humidification mask which claims to reduce dehydration during aircraft travel and acts as a bacteriostatic filter. Many AIS programs such as Netball, Athletics and Swimming feel confident that it is a useful product for alleviating symptoms of dehydration such as headache and malaise. No noticeable side effects have been reported.
Details: Retails at approximately AU $30.00 – Worn for 50% of total flying time – Reusable for 100 hours of air travel – Available from “Humidifier Technologies” PO Box 168, Neutral Bay, NSW.
Melatonin is a natural hormone released by the pineal gland in the brain which is involved in the regulation of the body’s internal clock. American researchers are currently manufacturing a synthesized version of melatonin which claims to improve alertness and help with sleep disturbances. Melatonin is currently unavailable in Australia and banned in every country but the US, where melatonin is sold in drug and health food stores. Research currently underway in Adelaide may provide more substantial information about these claims.
Details: Not approved for sale in Australia, however individuals can import up to three months supply for their own use. Relatively inexpensive retailing- under AU$15 for 60 three milligram capsules (a supposed two month supply). Preliminary studies recommend 3-5 mg, taken before bed for 5 consecutive days upon arrival. Melatonin is most effective when the athlete is exposed to a regular day and night cycle. Recommended dosage and optimal administration time is still under research.
Too often coaches and athletes ignore simple and practical procedures which can restore athletes’ pre-departure performance levels significantly faster following international air travel. A comprehensive approach to travel and planning ahead will optimize performance in athletes and contribute to success.