We don’t fully understand why we need sleep, but we do know that sleep has an amazing restorative and regenerative process on the body. We know that certain hormones are released during sleep such as growth hormone, testosterone and melatonin and that these hormones run the repair process. Sleep is divided in to two stages: non REM and REM sleep. Non REM sleep can be subdivided in to 4 stages that are associated with different brain waves:
- Stage 1: drowsiness and falling a sleep
- Stage 2: eye movement’s stop, heart rate and breathing slow down and muscles relax.
- Stage 3 and stage 4 are characterised by delta waves, with very little movement and being sound asleep or “dead to the world”
After this you pass in to REM sleep where there is rapid eye movement and dreaming. One complete cycle of sleep consists of the 4 stages of non REM and REM sleep and can be repeated anywhere from 4-6 times a night, each cycle taking between 90-110 minutes (Dement 2001). A healthy adult should spend 20-25% of their sleep in REM sleep.
Chronic sleep debt is becoming increasingly common that has detrimental effects on recovery from exercise and general health. In athletes a lack of sleep has been shown to lead to increased depression, tension, confusion, fatigue and anger in swimmers (Sinnerton and Reily T, 1992); decreased endurance in a treadmill run (Oliver et al 2009); and decreased performance and increased perception of effort in weight lifters (Reilly and Piercy, 1994). Spiegel et al (1999) demonstrated that carbohydrate metabolism and endocrine function were negatively affected by sleep deprivation to only 4 hours a night. Kripke et al (2002) have reported that less than 7-8 hours of sleep a night leads to an increased body mass index and Taheri et al (2004) have demonstrated that less than 8 hours sleep a night led to low leptin and high ghrelin, both of which negatively affect appetite and may lead to over eating and increased fat mass.
Therefore it seems that sleep deprivation may impair the immune and endocrine system (Reilly and Edwards, 2007), impair hunger and eating patterns and increase pain perception (Haack and Mullington 2005) that hinders the recovery and injury healing process post exercise.
Good sleep hygiene refers to adopting behaviours that typically promote improved quality and quantity of sleep and avoiding behaviours that interfere with sleep (Halson 2008). One of the best ways to improve sleep is to improve sleep hygiene. Sleep hygiene involves many things such as sleeping in a dark, quiet room, eating the right foods and nutrients throughout the day and avoiding foods and other things that retard sleep.
Sleeping in the dark
Sleeping in a room that is free of light pollution and noise is one of the most important things you can do to improve sleep. Melatonin is produced by the pineal gland and stimulated by darkness and suppressed by light. Even a little light from street lights coming through the curtains for instance may suppress melatonin. Melatonin is also an extremely powerful antioxidant and supports immune function; it is a direct free radical scavenger; it stimulates antioxidative enzymes and it lowers free radical generation (Reiter et al 2003), thus it seems adequate production during sleep is important for rest and recovery. Melatonin is produced from tryptophan via the serotonin pathway, so eating proteins rich in tryptophan such as chicken, turkey and cottage cheese as well as eating foods rich in B vitamins and magnesium seems pertinent to provide adequate raw material and cofactors. Melatonin has been found to decrease sleep latency and improve length of sleep (Atkinson et al 2003), however as it is a drug in the UK, using it needs to be done in conjunction with a team doctor. Using black out blinds, an eye mask or ear plugs can improve the quality of sleep by providing a dark quite environment.
High GI meals
It is believed that consuming high glycemic index meals before bed improves sleep. The hypothesis is that high GI meals increase insulin that helps to increase the uptake of BCAA’s in muscle and leave a higher free tryptophan to BCAA ratio. This allows more tryptophan to pass across the blood brain barrier, increasing serotonin / melatonin (Halson 2008). Afaghi et al (2007) have demonstrated that a high GI meal 4 hours before bed improves sleep onset latency by 48.6%compared to a low GI meal 4 hours before. However closer inspection of these results show that the high GI meal consisted almost entirely of rice which seems impractical to ask an athlete to eat for their evening meal, and that the low GI meal was actually high glycemic load (GL) and would also increase insulin and have the desired effect of the high GI meal. The actual figures demonstrated that the high GI meal helped subjects fall asleep 8.5 minutes faster than those eating the “low GI” meal, and stay asleep an extra 7.9 minutes. Although statistically significant, these results do not seem that astounding for an extra 15 minutes sleep and the detrimental effect on body fat of eating such high GI meals makes this advice obsolete. It seems more pertinent to eat a balanced meal 4 hours before bed or even have a bed time snack that has a moderate amount of carbohydrate.
Heart seven on the ulna side of the palm wrist crease is used to enhance sleep in Chinese Medicine. The use of small adhesive magnets on Heart 7 through the night, although not scientifically studied, can help some people to sleep better.
Simple relaxation techniques such as taking a warm bath before bed, reading or doing some stretching can help raise activity of the parasympathetic nervous system and aid sleep. Similarly listening to relaxing music with / or listening to subliminal delta waves may also induce restful sleep.
Factors that retard sleep
Numerous nutritional factors have been shown to retard sleep; namely alcohol (Feige et al 2006), caffeine (Bonnet and Arand 1992) and hyper hydration (Halson 2008). Consuming alcohol post exercise is a very poor rehydration strategy and should be avoided. However as part of a balanced lifestyle some athletes may enjoy a glass of wine with dinner occasionally which seems acceptable (however not after a game). Caffeine metabolism can vary from one person to another depending the expression of liver enzymes, however is a stimulant and drinking coffee or tea should be avoided in the evening. Some athletes will use caffeine as a pre game stimulant, the performance benefit of using caffeine during a night game / event needs to be evaluated along with the negative effect it may have on sleep and recovery from that game / event. Finally, athletes may over hydrate following night games / events and may subsequently wake frequently in the night to urinate. Although re-hydrating is essential athletes should be encouraged to consume a little less fluid that contains more electrolytes in order to hydrate and retain fluid post games / events.
Tryptophan is an amino acid found in meat, fish and eggs and it is metabolised to 5HTP, serotonin and eventually melatonin. A diet lacking protein, especially food rich in tryptophan such as chicken, turkey, eggs and cottage cheese combined with a deficiency co-factors in these reactions such as B vitamins and magnesium may retard the production of melatonin.
Athletes now take branched chain amino acids (BCAA’s) supplements as part of the post exercise recovery period, however the use of BCAA’s after night games / event may be contraindicated to getting good quality sleep. Increased BCAA’s in the blood decreases the transportation of tryptophan across the blood brain barrier leading to less free tryptophan to be converted to melatonin. Decreases in free plasma tryptophan have been shown to lead to disturbed sleep (Markus, et al 2005). The timing and dose of tryptophan is yet to be scientifically established, however using a dose of 1g before bed may be beneficial to improve sleep onset latency (Hartmann 1982).
Valerian is commonly used to treat insomnia and sleep disturbance. A systematic review in to use of valerian for sleep concluded the available evidence suggests that valerian might improve sleep quality without producing side effects. (Bent et al, 2006). A scientific does of valerian is yet to be established, however taking 2.5-5ml of valerian tincture may be very useful.
A supplement that can be particularly useful to aid sleep is magnesium. Although there are not many research trials to supports this, there is good clinical evidence to support its use with clients reporting much better sleep after magnesium consumption. There are many reasons to support this; magnesium is used as a co-factor in many chemical reactions especially in converting tryptophan to melatonin. Simply having a magnesium deficiency could retard this process leading to a lack of quality sleep. Research has shown that using 10mg of magnesium per KG of body weight is useful and tolerable for athletes to boost testosterone levels (Cinar et al. 2010), which for a 75kg male would equal 750mg. I may not be necessary to take that much before bed but taking 300-450mg (usually 2-3 capsules of magnesium) could be very useful.
Considered a member of the B vitamin family inositol can be manufactured in the human body. Although as yet there are no scientific trials to suggest inositol aids sleep, there is plenty of anecdotal evidence that it helps and is does not produce any side effects such as difficulty waking and drowsiness.
- Ensure good sleep hygiene by sleeping in a dark and quiet room
- Do something relaxing before bed such as stretching, reading or taking a hot bath
- Eat a meal 4 hours before bed that has some carbohydrate but not excessively high amounts
- Avoids things that retard sleep such as alcohol, caffeine and drinking too much plain water
- Consider acupuncture and the use of either melatonin (under the supervision of a doctor) or supplements such as valerian, tryptophan, magnesium or inositol to aid sleep