Shona L. Halson, Georgia Romyn and Michelle Cort
Most athletes are required to undertake significant travel for competition. This can have consequences for both physiological and psychological status and has the potential to impair performance. Nutrition is one aspect of travel which requires careful planning to minimise the risk of illness and to ensure nutritional goals are met. Obtaining adequate sleep when travelling (especially if crossing multiple time zones) can also be problematic for many athletes, and there is emerging evidence that nutrition may influence sleep quality and quantity and, therefore, may be useful to the travelling athlete. The influence of carbohydrate, protein (tryptophan), alcohol and caffeine may be important to consider when managing travel and jet lag in athletes. This chapter will discuss the key nutrition-related considerations for travel, including jet lag, training and competition schedule, accommodation and meal arrangements, availability of food and drink at destination, hygiene issues, climate and venue facilities.
LEARNING OUTCOMES
Upon completion of this chapter you will be able to:
• understand the causes and consequences of jet lag
• identify strategies to minimise travel fatigue and jet lag
• plan, prepare and execute effective travel nutrition
• identify some of the nutritional issues athletes face when travelling
• understand why sleep is important to athletes
• identify strategies to enhance sleep
• understand how nutrition may influence sleep.
JET LAG AND THE IMPACT OF TRAVEL ON PERFORMANCE
The competition and training schedules of elite athletes often require them to undertake frequent long-haul air travel that negatively affects the sleep–wake cycle. Accordingly, air travel can interrupt training schedules and increase the physiological and perceptual loads of athletes prior to competition (Fowler et al. 2014). With performance often required within days of arrival in a new time zone, it is important to develop a plan to combat the detrimental effects of sleep disruption, circadian process desynchronisation and travel fatigue so athletes can return to optimal performance as soon as possible. This will reduce the days lost to training following travel and may help to optimise competition readiness and performance.
Sleep–wake cycle
Also known as circadian rhythm, a daily pattern that determines when it is time to sleep and when it is time to be awake.
Circadian process desynchronisation
Disruption of the sleep–wake cycle/ circadian rhythm.
Jet lag is associated with rapid travel across time zones, such as flying east to west or west to east on an aeroplane (transmeridian travel). Circadian processes influence the physiological, mental and behavioural changes that occur daily on approximately 24-hour cycles. When circadian processes do not correspond with the external environment jet lag symptoms occur, and the severity of jet lag increases with the number of time zones crossed. The primary symptoms of jet lag are difficulty initiating and maintaining sleep at night, daytime sleepiness, impaired physical and mental performance, poor mood, appetite suppression and gastrointestinal complaints (Waterhouse et al. 2004).
Jet lag
A physiological condition experienced when circadian processes do not correspond with the new external environment.
Jet lag is not experienced with north-to-south or south-to-north long-haul travel as no time zones are crossed. However, this travel still involves exposure to mild hypoxia, cabin noise and cramped and uncomfortable conditions; some athletes may also experience anxiety (Youngstedt & O’Connor 1999). This leads to travel fatigue and sleep disruption, contributing to decreases in aerobic performance, reaction time, concentration, alertness, skill acquisition, mood, immune function, tissue regeneration and appetite regulation (Youngstedt & O’Connor 1999). A study of northbound long-haul travel on sleep quality and subjective jet lag in professional soccer players found that sleep was disrupted due to flight and competition scheduling, causing travel fatigue (Fowler et al. 2015).
Hypoxia
Deficiency in the amount of oxygen reaching the tissues.
MINIMISING TRAVEL STRESS
Jet lag and travel fatigue are of concern to athletes as they can compromise physical and cognitive performance. Sleep hygiene recommendations before, during and after the flight may help alleviate the negative effects of travel on sleep. Under normal circumstances, internal circadian processes respond to external cues from the outside environment. These cues are called zeitgebers and the most influential is sunlight and the light–dark cycle. Food, exercise, sleep and pharmacological interventions that mimic hormones involved in circadian processes are also zeitgebers but are generally weaker than sunlight.
Zeitgebers
External or environmental cues which synchronises our biological rhythms to the Earth’s 24-hour light–dark cycle.
One potential strategy to minimise jet lag is to use exposure to, and avoidance of, bright light. While natural sunlight has powerful phase-shifting properties, some laboratory-based research suggests that correct timing of artificial/indoor light exposure and avoidance can also be used to facilitate adaptation to a new time zone (Fowler et al. 2015). More research on the impact of scheduled artificial bright light exposure and avoidance on circadian process resynchronisation following long-haul aeroplane travel is required.
Melatonin is a hormone produced by the body at night, or under dark conditions, that signals night-time to the body. In normal circumstances, melatonin is secreted into the bloodstream between about 9 p.m. and 7 a.m. (Waterhouse et al. 2004), in line with the timing of the innate drive to sleep. Melatonin has several effects on the body, including dilation of blood vessels on the skin, which increases heat loss from the body, subsequently causing the drop in core body temperature required for sleep (Waterhouse et al. 2004). In the absence of melatonin, heat loss and the subsequent drop in core body temperature are affected and sleep onset and quality will be negatively impacted. Normally, melatonin is released in the body from approximately two hours before bedtime, provided there is limited light exposure at this time. When circadian processes are desynchronised with the external environment, melatonin secretion is incorrectly timed; this is one of the primary reasons for sleep disruption when jet-lagged. Therefore, melatonin may be used to treat jet lag, although the timing of ingestion is highly specific and individual. The dose of melatonin is also highly individual and, if the dose is too high, melatonin may remain in the bloodstream too long and act at the wrong time. Additionally, melatonin should be administered with caution in athletes as it is considered a medication, can only be prescribed by a doctor, is not readily available, and, in many cases, must be provided by a compound pharmacist.
It has been found that exercise lasting one to three hours can induce significant circadian phase shifts. Time of day at which exercise is completed, intensity of exercise, lighting conditions and age and gender of participants are complicating factors. Furthermore, most previous research in this area has been conducted on elderly patients, a population vastly different to elite athletes. However since athletes are highly likely to engage in training before and after travel, there is potential to schedule this training at the times most likely to correctly adjust circadian processes.
The strategies below may be used to minimise travel fatigue.
Box 21.1: Strategies to minimise travel fatigue
BEFORE TRAVEL
Sleep
• Sleep should be prioritised.
• Aim for at least eight hours of sleep per night in the two weeks leading up to travel.
• Bedtime and wake time should be kept consistent to give the best opportunity for good-quality sleep.
• Do not stay awake late at night before an early morning flight.
Planning
• Avoid intense training the day before and the day of travel to minimise muscle damage before flying.
• If possible, schedule long-haul flights to arrive at the destination late in the day so that the athlete does not need to stay awake all day before sleeping overnight.
• Book an aisle row or exit row to give more space and comfort, especially if the athlete is tall.
• Pack what is needed to be comfortable, such as a travel pillow, eye mask, earplugs, noise-cancelling headphones and blankets.
• Plan to bring entertainment.
• Pack as much as you can in advance and try not to leave this to the last minute.
Nutrition
• Fill your water bottle (after boarding) and drink enough water to stay hydrated.
• Does travel food meet your nutritional needs? Pack your own food for your flight and for the duration of your trip if required. Choose foods that fit with your nutrition plan for the current phase of training and competition; be mindful of carbohydrate and protein foods to maintain requirements.
Compression
• Put medical-grade compression socks on before the flight and wear them during the flight and for as long as possible after the flight. Compression socks reduce swelling and promote blood flow, reducing the risk of developing deep-vein thrombosis (DVT) and helping you feel better on arrival.
• DO NOT wear compression tights or tops, as these will not stop swelling in the hands and feet.
DURING TRAVEL
Airport and flight
• Arrive with plenty of time to check in, get through security and board without rushing.
• At check-in, ask for the seat you want (aisle, window, exit row).
• Once on the plane, ask if there are any spare seats or rows you can move to to stretch out after take-off.
• Ask when meals will be served so you can plan when you will sleep.
• Adjust your watch to the destination time.
Sleep
• Sleep as much as possible. Spread out where possible and get comfortable. Use ear plugs, noise-cancelling headphones, eye shades and neck pillows to improve sleep and comfort during travel.
• ANY sleep/rest is beneficial! Take what you can get.
Aeroplane exercises
• Athletes may suffer from DVT due to injuries, bruises and damaged muscles.
• Complete stretching, self-massage and light exercises every 1–2 hours (when awake) to increase blood flow and promote relaxation.
Hydration and nutrition
• Drink enough fluid to stay hydrated. If possible, eat meals at the time you will at the destination. To help avoid disruption to sleep, avoid large amounts of caffeine (<1 cup of coffee per four hours) and stop drinking coffee, cola and other caffeinated beverages before 4 p.m.
Compression
• Wear your compression socks for at least 1–2 hours (or as long as possible) after the flight. You may remove compression socks to do hydrotherapy or before sleeping at night.
Hydrotherapy
• If possible, use contrast showers (alternate between hot and cold water) or ideally a pool or beach hydrotherapy session on arrival to help reduce physiological stress.
Nutrition
• Avoid caffeine in the afternoon and evening.
The strategies listed below can be used to minimise jet lag.
Box 21.2: Strategies to minimise the effects of jet lag
SLEEP
• Prioritise sleep at night in the new time zone.
• Get to bed early and, if possible, sleep in the following morning.
• If you arrive early in the day, and feel you will not make it through the day without sleep, have a short (<90 minute) nap in the early afternoon.
LIGHT EXPOSURE
• Get outside and seek daylight in the new time zone. This can be coupled with some light exercise and stretching.
NUTRITION
• Eat meals at the usual time of day.
EXERCISE
• If possible, train at the time of day that you will be competing.
NUTRITION AND TRAVEL
Travel can heighten the risk of an athlete being unable to meet their nutrition goals or developing an illness. Unfortunately, this is often at a time when the outcomes of training preparation and competition performance are of greatest importance. Athletes should seek personalised advice, as nutrition recommendations vary and will be specific to each destination and athlete.
Table 21.1. An example of a travel nutrition risk management audit
| Risk | Risk management strategy in place? | Further strategy development required? | Level of risk? | Level of risk with strategy in place? |
| Example: Unknown food supply on flight | Call airline and discuss food provided. | Plan to take own snacks on board if airline cannot provide special meal. | Moderate | Low |
Planning
Preparation prior to departure can mitigate many of these risks to performance and health. One strategy that is useful for athletes and support staff to undertake well in advance of departure is a travel nutrition ‘risk management audit’.
Several questions must be answered within this audit, the first being, what are the risks to successful performance at the destination? Each ‘risk’ then needs to be further explored and a risk management strategy put in place. Table 21.1 shows an example of the audit process.
It is often useful to talk to other athletes, staff and coaches who have travelled to the destination previously. Their experiences can highlight issues that need to be considered during planning.
A timeline for strategy development and execution, along with allocation of roles and responsibilities, then needs to be developed.
Considerations that should be incorporated into the planning process include:
• itinerary
• training and competition schedule
• type of accommodation and meal arrangements
• familiarity with the destination—food and drink availability, hygiene issues, climate
• local dietary habits (for example, timing of meals)
• food and fluids provided by competition management/organisers
• distance between accommodation and training/competition venue(s)
• venue facilities (safe water supply, refrigerators, etc.).
An athlete’s specific nutrition goals need to be central to all planning. While some adaptability will be needed, a nutrition action plan for training and competition days should be made before departure so that major issues are avoided.
Common travel nutrition issues
Many of the common nutrition-related issues experienced by athletes who travel are presented in the following section, along with suggestions for how these issues could be mitigated.
Flights
A number of stresses can take place in transit that are independent of the time zones crossed.
Dry, pressurised air in the cabin of an airplane results in a need for increased fluid intake during flight. This is especially the case for long-haul flights, where significant dehydration could occur.
• Carry an empty water bottle and use the onboard taps (located near the flight attendant stations) to refill.
• Request additional fluids beyond those provided at meal services (these are invariably very small containers).
• Alcohol can contribute to dehydration and avoidance should be considered.
• Caffeine-containing fluids are a suitable choice to add to fluid balance if they are a regular part of an athlete’s diet.
Food supplied by airlines does not always meet the nutrition requirements of an athlete.
• Airlines tend to provide a limited range of foods. Special requests can be made, but airlines may not be able to meet an athlete’s requirements.
• Special meal requests to airlines should be made well in advance of flights.
• Athletes should take their own snacks on board. These are useful if the food provided does not meet requirements, or if unexpected delays occur.
• If an athlete’s energy requirements are high, they should take high-kilojoule snacks onboard to snack on, such as trail mix, muesli or energy bars.
• Alternatively, if the athlete has low energy needs they will need to be wary of snacking due to boredom. Taking some sugar-free chewing gum and drinking low-energy (kJ) fluids, such as water, can be a useful strategy to overcome this temptation.
Travel by road
If travelling via car or bus it is advisable to pack a small cooler or lunchbox with meals or snacks and fluids to ensure appropriate items are on hand. This will also be a more economical option than relying on over-priced service station items.
Gastrointestinal infections related to travelling are frequent among athletes and are often food- and fluid-borne.
• Education of athletes and support staff before travel is required.
• Many infections can be prevented by taking care with food and fluid choices, along with personal hygiene.
• Avoiding the local water supply in countries where potential pathogens could be consumed in this manner is essential. Care should be taken to avoid ice in drinks and to avoid brushing teeth with local water. Drinks should be consumed from sealed containers only.
• Beware that salads and peeled fruit may have been washed in local, contaminated water and are best avoided unless you are sure that they are safe.
• Unpasteurised dairy products should be avoided.
• Care should be taken to only eat meals that are either served very hot or cold.
• Using probiotics and prebiotics (see Chapter 23) both prior to departure and during the travel period can help minimise the risk of certain infections.
Additional food supplies
Packing a supply of food and sports foods from home will be useful if the food supply (type, quality, safety) is unknown, the athlete is a fussy eater, or if they rely on specific products around training sessions and competitions.
Always check ahead with customs/quarantine authorities to identify what foods are restricted.
Environment
An athlete’s nutrition needs may be different at the destination due to the environment (for example, due to altitude or heat; see Chapter 22).
Develop a plan to counter any negative effects of these changes before leaving home.
Eating out
Eating out can be tricky in terms of meeting nutrition requirements.
• Try to check out menus online before selecting a restaurant.
• Special dietary needs should be organised ahead of time.
• If travelling with large groups of athletes, calling ahead and arranging for a certain number of specific meals to be ready to serve can help reduce wait times.
Buffets
Buffets offer a large variety of foods and it is easy to eat more than required in this setting.
• It is important that the athlete is familiar with their own nutrition goals.
• Athletes should be encouraged to do ‘a lap’ of the buffet or dining hall to gauge what is on the menu before plating their own meal.
• The athlete should be selective with their choices rather than taking some of everything on offer.
• Leaving the dining area as soon as the meal has been consumed helps to prevent the temptation to go back for more.
Self-catering
Staying in apartments that have cooking facilities allows for flexibility in meal times and food options.
• Using an online shopping service can be useful if ordering large quantities (for example, when cooking or ordering for a whole squad).
• Having ‘go-to’ recipes that require few ingredients and minimal cooking equipment (often sparse in rented accommodation) is suggested.
Hydration
Monitoring hydration using morning body weight or with urine specific gravity testing is advisable, especially after long-haul flights or in hot climates.
• In hot and humid countries and sporting venues, sweat rates can be significant.
• Regular body weights of individual athletes before and after exercise sessions are useful to determine hydration status.
• Drinking large volumes of water, especially during hard exercise, may lead to hyponatraemia. Use of a sports drink or electrolyte drink can help to address this problem.
Sleep
Sleep is increasingly recognised as one of the critical foundations of an athlete’s training program. Sleep is considered the best recovery strategy available to athletes due to its physical and psychological restorative effects. Getting a good night’s sleep can decrease injury risk, improve reaction time, coordination, concentration, memory, learning, motivation, mood and immunity and increase performance. Sleep also aids the repair and regeneration of muscles and tissues due to important hormonal release (growth hormone in particular) that occurs during sleep (Halson 2014).
Sleep studies with training athletes are an emerging area of research, and most studies have found that athletes have poorer-quality sleep and less time asleep than is recommended (Lastella et al. 2015; Leeder et al. 2012; Sargent et al. 2014). This effect is likely exacerbated by long-haul or frequent travel. Given the importance of sleep and the poor quality and amount of sleep experienced by many athletes, strategies to enhance sleep should be considered (see Box 21.3).
Box 21.3: Strategies for a good night’s sleep
BEDROOM
• The bedroom should be cool (19–21°C is best), dark, quiet and comfortable.
• The bed and pillows used are important. They should be supportive and requirements will vary according to individual physical attributes.
ROUTINE
• Create a good sleep routine by going to bed at the same time and waking up at the same time every day (or as often as possible).
• A before-bed routine can help the body prepare for sleep. The routine should start about 30 minutes before bedtime and be consistent. This may include activities such as cleaning teeth and reading a book.
ELECTRONICS
• Avoid watching television or using smartphones/computers in bed. These can steal sleep time and form bad habits.
AVOID WATCHING THE CLOCK
• Many people who struggle with sleep tend to watch the clock too much.
• Frequently checking the clock during the night can wake you up (especially if you turn on the light to read the time) and may reinforce negative thoughts.
GET UP AND TRY AGAIN
• If you haven’t been able to get to sleep after about 20 minutes, get up and do something calming or boring until you feel sleepy, then return to bed and try again.
• Sit quietly on the couch with the lights off (bright light will tell your brain that it is time to wake up).
FOOD AND FLUID
• Avoid the use of caffeinated food and fluids later in the day.
• Do not go to bed after consuming too much fluid; this may result in waking up to use the bathroom.
• Utilise a ‘to-do’ list or diary to ensure organisation and prevent unnecessary over-thinking while trying to sleep.
RELAX
• Investigate relaxation or breathing techniques.
NUTRITION AND SLEEP
Although our knowledge of how nutrition impacts sleep is still somewhat sparse, it is an area of growing interest to researchers and athletes alike. Some nutrition strategies are known to impact both sleep onset and quality, and can be manipulated by athletes to achieve improved sleep outcomes.
Several brain neurotransmitters are associated with the sleep–wake cycle. Specific nutrition interventions can act on these neurotransmitters to influence sleep (Halson 2014). The rate of synthesis and function of the neurotransmitter 5-HT (which in turn stimulates the production of melatonin), is influenced by the availability of its precursor tryptophan (Grimmett & Sillence 2005). Tryptophan is an amino acid found in foods such as eggs, meat, poultry and dairy products.
Tryptophan must be transported across the blood–brain barrier for it to have its sleep-inducing impact, and carbohydrate is needed to support this process. Therefore, a drink, snack or meal that contains both tryptophan and carbohydrate could help induce sleep. Popular sleep-inducing snack options include a milk drink, yoghurt or tuna and crackers.
Alcohol may also help a person feel sleepy and fall asleep more quickly. However, once alcohol levels in the blood fall, sleep is disrupted and the amount of quality sleep is reduced (Ebrahim et al. 2013). Athletes should be made aware of this so that an informed choice around alcohol consumption can be made.
Caffeine has a role in the performance plan of many athletes, as well as being a regular feature in many athletes’ habitual eating plans. Given caffeine can delay an athlete’s natural signals to go to sleep, its use as an ergogenic aid in sport needs to be carefully planned. The athlete should identify the dose and timing of caffeine required to maximise performance and minimise sleep disturbances by trialling caffeine intake strategies in training (see Chapter 12).
SUMMARY AND KEY MESSAGES
Effective planning and preparation for travel in elite athletes is essential to optimise performance and reduce the risk of illness. Reducing the symptoms of jet lag can aid in reducing training days lost due to travel. Through careful planning and execution of travel, nutrition and sleep strategies, it is possible to minimise some of the negative influences of travel in athletes. This may have a positive influence on health, wellbeing, mood and, importantly, performance.
Key messages
• Jet lag can result in physiological and psychological symptoms that may impair performance.
• Light, exercise, caffeine and melatonin may be used to manage jet lag, although these need to be used with caution.
• Strategies such as sleep, planning, nutrition, exercise and compression garments can be used before and during travel to manage travel fatigue and jet lag.
• Nutritional considerations such as nutrition provisions in transit, food and fluid safety (hygiene), meal availability at the destination and food and fluid provided by the training or competition venue are important.
• Destination eating options (eating out, buffets and self-catering) have issues that need to be planned for prior to travel.
• Monitoring hydration after travel is recommended.
• Optimal sleep is important for athletes’ performance as well as managing jet lag.
• The role of nutrition in enhancing sleep is likely to become an important area of future focus.
REFERENCES
Ebrahim, I.O., Shapiro, C.M., Williams, A.J. et al., 2013, ‘Alcohol and sleep I: Effects on normal sleep’, Alcoholism: Clinical and Experimental Research, vol. 37, no. 4, pp. 539–49.
Fowler, P., Duffield, R., Howle K. et al., 2014, ‘Effects of northbound long-haul international air travel on sleep quality and subjective jet lag and wellness in professional Australian soccer players’, International Journal of Sports Physiology and Performance, vol. 10, no. 2, pp. 648–54.
Fowler, P., Duffield, R., Morrow, I. et al., 2015, ‘Effects of sleep hygiene and artificial bright light interventions on recovery from simulated international air travel’, European Journal of Applied Physiology, vol. 115, no. 3, pp. 541–53.
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Sargent, C., Lastella, M., Halson, S.L. et al., 2014, ‘The impact of training schedules on the sleep and fatigue of elite athletes’, Chronobiology International, vol. 31, no. 10, pp. 1160–68.
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Youngstedt, S.D. & O’Connor, P.J., 1999, ‘The influence of air travel on athletic performance’, Sports Medicine, vol. 28, no. 3, pp. 197–207.