Oh sweet, sweet sleep. One of life’s basic and often overlooked luxuries that so many of us miss out on. Yet sleep is recognized more and more for its important role in both health and athletic performance. But what exactly is that role, and can nutrition play a part in improving our sleep?
The Role of Sleep
It seems logical that sleep plays a role in “recharging” but let’s take a deeper look at what we know of its function to date. First, there are two main factors to sleep: the length of sleep (such as hours per night, plus naps) and the quality of sleep (the experience of sleep and the circadian timing/phases) (2). Sleep is actually a very active state wherein multiple processes occur, such as (2):
· Restoring the immune and endocrine system,
· Managing inflammation, and
· Facilitating learning, memory, and overall cognitive function.
Given these functions, it’s not surprising that a lack of appropriate sleep can result in many undesirable side effects, such as (3, 4):
· Decreased tissue repair, or the ability to repair and rebuild muscle,
· Decreased cognition, which translates to problems with coordination and focus,
· Altered mood, often leading to irritability,
· Suppressed immunity, resulting in more frequent illnesses such as upper respiratory infections,
· Changes to hunger and glucose tolerance, contributing to overeating and development of chronic diseases such as diabetes, and
· Alterations to your circadian rhythm, which makes getting back on track with sleep even harder.
So what’s an appropriate amount of sleep? The National Sleep Foundation suggests adults need at least 7-9 hours of sleep per night (5). While research specifically in sleep for athletes is a growing area, the current evidence suggests athletes likely need more sleep than your average adult, potentially up to 9-10 hours, but get less, with a handful of studies in elite athletes suggesting average sleep is between 6-7 hours (6).
Common factors impacting sleep include training or competition times (for example, late games or early morning workouts); adrenaline after just finishing a game or anxiety about the competition tomorrow; and training-related inflammation or soreness which can interrupt sleep quality.
Additionally, in the battles between sleep and work, sleep and videogames, or sleep and Netflix – sleep often loses. Finally, over 50 million American adults are affected by sleep disorders (1).
Sleep Hygiene
Before we talk about how nutrition can benefit sleep, let’s lay the foundation with basic sleep hygiene. The National Sleep Foundation suggests the following:
· Stick to a similar sleep/wake cycle throughout the week. This may be the most challenging for athletes based on training and competition schedules.
· Keep your bedroom at a comfortably cool temperature and ensure you have the ability to reduce light and sound. If traveling for training or competitions, find the hotel room thermostat and pack ear plugs!
· Avoid electronics within 30 minutes of bedtime.
· If you haven’t already, get a comfortable mattress and pillows. Consider bringing something on the road when traveling.
· Practice relaxing rituals before bed if helpful, such as brief meditations or relaxation exercises.
Also, if you have chronic sleep issues, such as snoring, waking up out of breath, waking routinely in the middle of the night, or never feeling rested despite “sleeping” for 8 hours, consider discussing this with your physician to determine if an underlying sleep disorder is at play.
The Role of Nutrition
So how can nutrition benefit sleep? There are certain macro and micronutrients, along with intake patterns, that appear to be more beneficial for sleep. It’s also likely that the relationship is bidirectional in some instances – certain nutrients impact sleep, and sleep impacts how we metabolize certain nutrients. Keep in mind, nutrition is unlikely to make up for gaping holes in sleep hygiene, but here are some nutrition-related suggestions to improve your sleep:
1) Keep your carbs. Adequate intake of carbohydrates (to support training) may reduce the time to fall asleep (sleep onset or latency). Additionally, higher glycemic index carbohydrates (think white rice, white bread, refined cereal) consumed greater than1 hour before bed have been shown to reduce sleep onset (2,3).
2) And keep your protein. Diets higher in protein have also been shown to reduce time to fall asleep (2,3). This may potentially be due to the intake of tryptophan which is a precursor to serotonin and melatonin (2).
3) Watch the fat. Consuming an overall high fat diet has shown a reduction in sleep quality (3).
4) Be mindful of eating too little. Those attempting to manage body weight or composition via a reduced calorie diet take note: consuming fewer calories can disrupt sleep as well (3). Perhaps another reason to avoid body composition changes during heavy training or competition periods?
5) Try melatonin. Melatonin is secreted from the pineal gland in line with the light-dark cycle driving our circadian rhythm. Melatonin can be taken in supplement form and when appropriately timed with sleep, has shown some benefit with sleep onset but likely depends upon the underlying sleep issue. For those traveling, using melatonin could assist with transitioning between time zones. Anecdotally, some individuals report more and/or vivid dreams with its use. There is some evidence suggesting tart cherry juice, a natural source of melatonin, could provide a similar benefit, in addition to reducing sleep-disrupting inflammation.
6) Consider the kiwi. Kiwifruit has recently been research for its effect on sleep due to its serotonin and antioxidant content (2). More research is needed, but it can’t hurt to include more kiwifruit!
7) Watch your caffeine and alcohol intake. Caffeine’s effects can vary from person to person, but on average it can remain in your system up to 12-15 hours after intake. Typically, it results in increased sleep onset time and decreased sleep quality. Learn your own tolerance with caffeine. Alcohol is also a known sleep-disruptor – avoid excess intake prior to bed.
8) Watch overeating or overdrinking. Large meals or high fluid intake right before bed can both interrupt sleep. Aim for at least 1-2 hours of vertical time after a meal, and get your fluids in throughout the day instead of end-loading.
Is nutrition the primary determinant in sleep time and quality? Certainly not, but if you are taking all the right steps to have good sleep hygiene and want to improve your recovery and performance, why not give nutrition a try!
1) National Institutes of Health: National Center for Complementary and Integrative Health (2015) Sleep Disorders: In Depth. Available at: https://www.nccih.nih.gov/health/sleep-disorders-in-depth.
2) Doherty, R., Madigan, S., Warrington, G., and Ellis, J. (2019) ‘Sleep and nutrition interactions: Implications for athletes’. Nutrients, 11, pp. 822-835.
3) Halson, S.L. (2014) ‘Sleep in elite athletes and nutritional interventions to enhance sleep’. Sports Medicine, 44, pp. S13-S23.
4) Halso, S.L. and Juliff, L.E. (2017) ‘Sleep, sport, and the brain’. Progress in Brain Research, 234, pp. 13-31.
5) Golem, D.L., Martin-Biggers, J.T., Koenings, M.M., Davis, K.F., and Byrd-Bredbenner, C. (2019) ‘An integrative review of sleep for nutrition professionals’. Advanced Nutrition, 5, pp. 742-759.
6) Fullager, H.H., Skorski, S., Duffield, R., Hammes, D., Coutts, A.J., and Meyer, T. (2015) ‘Sleep and athletic performance: The effects of sleep loss on exercise performance, and physiological and cognitive responses to exercise’. Sports Medicine, 45, pp. 161-186.