Sleep is essential for cognitive function, mood, energy levels, athletic performance and recovery from exercise. Many athletes struggle to fall and remain asleep for a significant amount of time. This lack of sleep (also known as sleep deficiency) can have many negative side effects, such as hindering exercise recovery and reducing training adaptations. Additionally, sleep deficiency is associated with an increase in calorie intake and a decrease in activity and exercise levels, which can ultimately lead to weight gain. Let's take a look at a few nutritional strategies that may enhance your sleep quality and quantity:
- Avoid/keep caffeine to a minimum in the late afternoon and evening. If you do enjoy a hot drink in the evening, I would recommend drinking tea instead of coffee, due to its significantly lower caffeine content (an average of 25mg in tea compared to 85mg in coffee). As we all know, caffeine is a potent stimulant, and with a half-life of approximately 4-6 hours, the stimulatory effects take a significant amount of time to wear off.
- Avoid consuming high glycemic index (GI) carbohydrates within 1 hour of sleep. However, a meal containing high GI carbohydrates can improve sleep quality and decrease the time taken to fall sleep if consumed over 1 hour before sleep. High GI carbohydrates stimulate a large insulin response, subsequently increasing the uptake of protein (large amino acids) into the muscles. This uptake of protein into the muscles allows more tryptophan to cross into the brain (as other proteins and tryptophan compete for transport into the brain) and produce more serotonin. Serotonin is a neurotransmitter that increases feelings of tiredness and lethargy.
- Restrict fluid intake late in the evening, as excess drinking can result in hyper-hydration (becoming over hydrated), and waking up several in the night to urinate. Sip water slowly throughout the afternoon and re-hydrate as soon as possible after exercise to ensure you do not have to drink large volumes in the evening.
- Ensure an adequate amount of protein and carbohydrate is present in your diet, as diets insufficient in these nutrients are associated with a decrease in sleep quality.
- As well as being linked with a decrease in sleep quality and quantity, alcohol inhibits the release of anti-diuretic hormone, a hormone that promotes the retention of water and the regulation of fluid balance. Therefore, drinking alcohol has a diuretic (water loss) effect leading to urination during the night and potential dehydration.
- Some athletes struggle to sleep when feeling hungry, whereas others like to go to bed feeling satiated. Adjust your meal times, food intake and snacks to suit your preference. For example, protein has a larger satiating effect than carbohydrate or fat, making you feel fuller for longer.
- Consuming foods high in tryptophan or supplementing with tryptophan (1g), 2-4 hours prior to sleep may shorten the onset of sleep. As mentioned previously, tryptophan is converted into serotonin in the brain. Serotonin is a neurotransmitter that increases feelings of tiredness and lethargy; therefore, increasing tyrptophan through the diet may increase serotonin levels and enhance sleep. Foods high in tryptophan include: milk, fish, turkey, chicken, eggs, cheese, pumpkin seeds and beans.
- Finally, herbs such as Valerian are associated with improving sleep quality and the onset of sleep. The roots of Valerian plants are used as a herbal medicine to treat insomnia and anxiety disorders. I would only recommend using herbal medicine once all other methods of improving sleep have been implemented.
References: http://www.ncbi.nlm.nih.gov/pubmed/24791913 http://www.ncbi.nlm.nih.gov/pubmed/17284739 About the Author Mark Funnell holds a BSc (Honours) degree in Sport and Exercise Science and an MSc in Sport and Exercise Nutrition from Loughborough University. He is currently working as a Performance Nutritionist for the England and Wales Cricket Board with both the England Women’s Academy and Midlands Regional Disability Cricket squads. Additionally, Mark is a graduate member of the Sport and Exercise Nutrition Register (SENr), an ISAK Level 1 Anthropometrist and a UK Anti-Doping advisor.