Sleep is vital for physiological and psychological functions that may be particularly important to athletes. Sleep deprivation can have significant effects on athlete performance, especially in high intensity, sub-maximal, prolonged exercise. Poor sleep can also negatively affect mood, learning, memory, cognition, pain perception, immunity and inflammation. These factors can all ultimately reduce an athlete’s nutritional, metabolic and hormone status and hence potentially reduce physical and mental health.
Recent evidence as well as anecdotal information suggests that athletes may experience poor quality and/or quantity of sleep, especially when compared to the general population. Given the importance of sleep for optimal health and performance, a number of nutritional interventions have been investigated to determine if they can increase sleep quality and/or quantity. While research is minimal and somewhat inconclusive several practical recommendations regarding nutrition and sleep may be suggested (1):
High glycemic index (GI) foods such as white rice, pasta, bread and potatoes may promote sleep; however they should be consumed more than one hour prior to bedtime.
Diets high in carbohydrate may result in shorter sleep latencies.
Diets high in protein may result in improved sleep quality.
Diets high in fat may negatively influence total sleep time.
When total caloric intake is decreased, sleep quality may be disturbed.
Small doses of tryptophan (1g) may improve both sleep latency and sleep quality. This can be achieved by consuming ~300g of turkey or ~200g of pumpkin seeds.
Melatonin and foods which have a high melatonin concentration may decrease sleep onset time.
Micronutrients
Micronutrients may also be important for sleep as they may have an involvement in the way the brain regulates sleep. While the scientific research in this area is minimal, a recent review suggested that there is an association between sleep duration and micronutrients, with sleep duration positively associated with iron, zinc and magnesium, and negatively associated with copper, potassium and vitamin B12 (2).
Conclusion
For athletes wishing to enhance their sleep, they should initially focus on optimal sleep hygiene practices. Consuming a balanced and healthy diet may increase the chances of obtaining a good night’s sleep. It is also important to appreciate that when restricting dietary intake, sleep may be impaired and therefore consideration should be given to when this occurs in the training program. Finally, identifying and correcting any deficiencies in micronutrients such as iron, zinc and magnesium may result in improvements in sleep.
References
1. Halson SL. Sleep in elite athletes and nutritional interventions to enhance sleep. Sports Med 44 Suppl 1: S13-23, 2014.
2. Ji X, Grandner MA, and Liu J. The relationship between micronutrient status and sleep patterns: a systematic review. Public Health Nutr 20: 687-701, 2017.