This blog continues the ‘Top 10 sleep principles’ focusing on travel and sleep
Travelling
In our previous post we considered general sleep issues during training. We also suggested that routines were the guardians of good sleep. It’s also the case that people tend to sleep best in familiar surroundings. However, whether the destination is a competition venue or a training camp, competitive careers will demand travel away from home. In this post we continue our Top 10 principles of good sleep management by focussing on travel, and its consequences, in elite sport.
5. Maintain personal sleep routines away from home. New sleep environments tend, initially, to be associated with lighter sleep and longer sleep latencies (a phenomenon referred to as the ‘first night’ effect). You can combat this by maintaining a ‘new bedroom’ ritual when you arrive at your accommodation. Make time to set out your bed-time stuff (PJs, toilet bag, etc.) so that things will be ready when you return for the night. Lay out your toiletries and arrange things around your bed. This has the important effect of familiarising you with, and ‘personalising’ a novel sleep environment. Try to preserve your pre-sleep habits and routines – these are important behavioural ‘cues’ for sleep. Make sure you pack any items which support these behaviours (like photos, books, blankets or teddies!), and consider taking your own pillow.
6. Learn to deal with travel fatigue and jet-lag. International or ‘long-haul’ travel impacts sleep in 2 ways: through jet-lag (when your body clock is out of synch with the local time at your destination); and through ‘travel fatigue’ (the normal weariness arising from, for example, a very early start to catch the plain, a prolonged period of wakefulness in flight, or the accumulated stress of travelling). Travel fatigue is rapidly reversed (after your first good sleep). Jet lag, however, can have a lingering effect on sleep routines and daytime behaviour, as explained in the following Qs & As.
What does jet lag affect? Most bodily functions are influenced by a biological clock. When you wake, when you sleep, when you feel hungry, when you go to the toilet, when you feel most alert, and when you feel least alert are all synced with the time of day. So, when we are out of sync, almost everything is affected: we can feel sleepy during the day; alert (and hungry) in the night; and find that we need to use the bathroom at odd times. The severity and duration of these symptoms is largely dependent upon the number of time zones crossed and the direction of travel taken.
How long does jet lag last? The symptoms of jet lag will persist until we re-sync with local time. The time taken to re-sync will depend on how far we travel, and whether we fly west or east. Flying west (for example, from London to Rio) stretches the day, while flying east (London to Tokyo) compresses the day. Generally, we cope better with days which are stretched. As a ‘rule of thumb’, full re-adjustment takes about 1 day for each (whole hour) time zone crossed when flying east, but only half a day for each (whole hour) time-zone crossed when flying west. But do keep in mind that, within any squad, adjustment rates will likely differ among individual athletes.
How can I avoid jet lag? Easy; stay at home! But however fit and disciplined you are, and whether or not you sleep on the plane, if you fly across time zones to arrive at your destination, some degree of jet lag is inevitable.
Can I help my body re-sync? Yes; adopt local time as soon as possible, and strategically use environmental time cues (e.g. sleep, exercise and meals) to maximise adjustment; light exposure provides an especially powerful stimulus for adjustment. Light and darkness, detected by special non-image forming receptors on the retina, influence the production of the hormone melatonin which plays an important role in synchronising the body clock with night and day. Simply put, light reduces melatonin, which ‘tells’ the body it’s daytime and helps mediate alertness.
Darkness, on the other hand, allows melatonin levels to rise, which ‘tells’ the body it’s night-time, and helps promote sleepiness. Problem is, once entrained, melatonin levels will continue to rise and fall according to the internal clock until re-synchronisation gradually takes place (hence, jet-lag). But we can help to ‘overwrite’ the existing programme by systematically seeking light exposure at times when we wish to suppress melatonin levels and promote wakefulness (and vice versa). So, following eastward travel, seek bright light after your body temperature ‘trough’, which occurs roughly 2-3 h before your body clock wake-up time (typically 4-5 am for a 7 am normal wake-up time at home) and avoid light prior to this point. Following westward travel the opposite applies, so seek light before this ‘trough’ (and avoid light after this point).
Of course, avoiding light entirely may be unrealistic (particularly if it is daytime in your new location). But you can minimise light exposure by not going outdoors, by avoiding sitting near windows and by wearing sunglasses with high ultraviolet protection. It is also sensible to time training sessions outside of the body clock night (when possible), and certainly outside the body temperature ‘trough’, when alertness and motivation to train is, at least initially, likely to be at its lowest. And however tempting, avoid long sleeps during the local day-time, as this can ‘anchor’ your biological rhythms to the wrong time of day, and will actually increase the severity of jet lag symptoms. So again, be a smart napper (e.g. sleep for no longer than 30 min) to help manage fatigue during the day time.
And a good point to remember is, if you’re competing abroad, remind your friends and relatives of the time difference between the UK and your destination to avoid being called at inconvenient times (better still, switch your phone off – completely off – when you’re in bed; prioritise sleep).
Will melatonin tablets help? Possibly; melatonin is a chronobiotic which, if used appropriately, can facilitate synchronisation and mitigate the impact of jet-lag (melatonin is not on the WADA prohibited list*). However, it is not a ‘magic’ pill, and its effectiveness in managing jet-lag has been challenged. In Europe, melatonin is available only on prescription (and in the UK, only for adults aged 55 years and older). The use of this product, therefore, must be discussed with a sport physician.
Finally, calibrate your expectations. Travel, one way or another, will affect your sleep – that’s normal. What’s also normal is that even the most challenged sleep will rapidly adapt.
About the authors
Professor Kevin Morgan is the Director of Clinical Sleep Research Unit, School of Sport, Exercise and Health Sciences, Loughborough University.
Luke Gupta is a Physiologist with the English Institute of Sport, Bisham Abbey National Sports Centre