Sport and sleep

All demanding sports men and women have the fear of suddenly feeling drained. It is a physical exhaustion that seems to occur without any reason whereas the subject, who trains regularly, can stand much bigger efforts.

In practice, the interview often puts forward a bad management of sleep during the week(s) before the event.

This passing loss of shape often corresponds to a sleep deprivation or life events with a bad influence on sleep efficiency.:

• The sports man or woman’s sleep is rich in slow wave sleep, but that good quality sleep depends on a regular keeping up with training.
• In the case of a forced immobilization, for example, the disappearance of deep sleep (stages 3 and 4) to the advantage of light sleep (stage 2) can be evidenced on the "sleep records".

The quality of the sports man or woman’s sleep is thus very sensitive to changes in life related to "somnotoxic" events.
Information about sleep and about the ways to cope with that vulnerability, especially at home, should be an integral part of the competition training.

Because sleep enhances even more the quality of sleep, it can end in pseudo-insomnia charts in short sleepers (the sleep duration decreases with the strong power and the efficiency of sleep).

On the opposite, a sudden stop in training (because of an injury, for example) in a high-level sportsman or woman causes an immediate change in sleep and carries along the appearance of multiple functional disorders within a couple of weeks despite a lengthened total sleep time (cf. "Hypo-sleep syndrome").

In that case, it is necessary to try to compensate the fall of the physical (caloric) expense by acting more passively on the body temperature (sauna) or with another form of physical exercise during convalescence ("thermotherapy").

Considering jetlag

Some sportsmen or women are confronted to journeys by plane over several time zones (Cf "jetlag" for a competition that has been programmed short after their arrival.
That jetlag though penalizes their performances for several weeks.

The coming Olympic Games in China will probably show it because the European sportsmen and women will be "at the antipodes", the opposite extreme of their chronobiological rythm.
A preventive strategy consists in modifying the schedules for going to sleep and getting up before departure, in order to anticipate on the rythm of the destination country (advanced for a trip to the East, delayed for a trip to the West).

The chronobiological resynchronization (of the two pendulums of sleep) is very slow. The nocturnal rythm of cortisol (an essential hormone especially for a sportsman or woman) needs three weeks to compensate a jetlag of six hours to the West and it sometimes takes up to three months when it is towards the East).
It is thus a matter of a true preventive chronotherapy which is hard to put through but it is nevertheless the only way to manage to arrive in a good physical condition if one doesn’t have the time for it once he/she is there.

The knowledge of the "somnications" which allow to influence the period of the sleep pendulums is thus essential.
The coach of a high-level sports man or woman must know chronobiology.

Performance and chronobiology.

The physical (and intellectual) performances are at their best at the maximum of the body temperature in the end of the afternoon.
Body temperature changes under the influence of internal (cortisol, melatonin, growth hormone, ...) and external (sport, noise, meals, light...) synchronizers.
It is, besides, slightly shifted forwards or backwards depending on if the subject is a morning or an evening person in a marked way (cf. circadian typology).

Particular case of the ocean-going sailor

All the sailors are submitted to shifted schedules when they are on the sea : the watches.
Traditionally, the last watch (4 AM - 8 AM) has the reputation of being the hardest.
In practice, the sailors (like the nightworkers) adapt themselves to the imposed schedules. They often spontaneously adopt the good sleep hygiene rules. (For example, they prefer to eat something before they go to to sleep in order to be in a better shape during their watch rater than the opposite.)


The situation is even more extreme in the case of the solitary navigator. Studies have been made for that sport where sleep management is one of the keys to success.
The most propitious moments for recovering are between 3 and 6 AM and between 2 and 6 PM. Short periods of sleep around 15 to 20 minutes also have a beneficial effect when used "in emergency" to restore a correct level of attention.

Cf. Chronobiological adaptations to the constraints of the high sea race (in French):
"On the ocean, these men are submitted to duration constraints that are not encountered anywhere else ... The activity on board often depends on the boat’s demands and, despite the never stopping noise, the violent moves, the continuous moistness, one must live, sleep and eat ..." (Dr Jean-Yves Chauve, 1997).

The solitary navigator prepares him/herself before the race’s departure by accumulating as much sleep as he/she can (stable and natural sleep schedules - no sleeping pills nor alcohol - regular sport and sauna, very short nap (if necessary) and/or relaxation in the start of the afternoon).
In the beginning of the race, he/she will have to stay awake the longest possible but his/her perfect knowledge of the chronobiology os sleep (and of his/her personal characteristics : the chronotype) will keep him/her from reaching the exhaustion stage where the risk to make a wrong manœuvre is important.

As long as the race lasts, the sportsman or woman will have to manage sleep pressure with short naps distributed over the 24 hours of the day.
The total sleep time may go down to 3 to 4 hours in 24, which corresponds to 15/30 minutes every two hours.
To be able to do that, he/she must (ideally) avoid stimulants like coffee which would cause the debt to be passed and a quick fall of performances.
The sailor must, therefor, be a good sleeper (and need no kind of "sleep help") to be able to sleep on demand when the sailing conditions allow him/her. (Despite the noise, he/she may not use earprops in order to be able to hear all changes of speed of his/her boat....even deep asleep).

That kind of sleep made of short "naps" distributed all over the nycthemeron (a day and a night define the duration of a nycthemeron) is called polyphasic sleep.
Some experiments have been made which tend to show that it is possible to reduce sleep duration down to 3 to 4 hours in 24 without performance loss (but the small number of tested subjects does not exclude that these were in fact very short sleepers).

But, if it is possible to reduce sleep duration that way (as long as a race lasts... or a fight ...), it is absolutely impossible to reduce one’s need for sleep.
Chronic sleep deprivation expresses through a fall of the physical and intellectual performances and can even lead to hallucinatory phenomenons.

Some ill-prepared navigators have reported, that way, true episodes of hallucinations (a high speed train passing by in the far, a fish woman...), others break the boat because of a bad estimation of what decision to take ... (The sleep debt is at the root of many shipwrecks like that of the Guadeloupean skipper Claude Bistoquet, on his own reefs, at the arrival of the "Route du Rhum" in 1994).

On firm ground, the navigator will quickly get rid of his/her sleep debt, in only one or two fitful nights.
The (homeostatic) ability to catch up sleep is very powerful : a phenomenon called "of compensatory rebound occurs with a decrease of the transition phases (made of light sleep) to the advantage of recovery sleep rich in slow waves and REM sleep (see "sleep iconography".

NB. That ability to "stand" and to "recover" changes from one individual to the other (everybody is not a high-level sportsman or woman).
Many insomniacs are constitutive very short sleepers and show great adaptation abilties towards sleep deprivation. Thus, they manage to keep going with normal performances despite their dramatic nights.

All in all : we are all high level sportsmen and women !

The good sleeper is the one who goes to sleep trustfully and wakes up fit.
Like every human being, the sportsman or woman is genetically programed to live during the day and sleep during the night according to a 24 hours rythm which is submitted to the influence of external synchronizers, the "time givers" or "Zeitgeber".
A perfect knowledge of the nap’s user manual and the other "somnications’" (like light and heat) is necessary to respond to the challenges that the modern world’s rythm impose on us.

An unstable system in balance

Think about your chronobiological rythm with the help of three interactive or downloadable tests: Evening or morning person; long or short sleeper, flexibility or rigidity of sleep.