When people talk about the keys to living a healthy life and performing at your best, exercise and diet are always front and centre. Rightly so, as exercising at least 150 mins per week at moderate to vigorous intensity and eating a well-balanced diet rich in green leafy vegetables, fruits, grains and seafood and low in red meats and saturated fats are essential for longevity and a healthy life. But there is a third pillar that is regularly overlooked that is just as important as diet and exercise and that is sleep.
Sleep deprivation can be due to sleep disorders like insomnia and sleep apnoea. These disorders are often associated with symptoms such as difficulty falling asleep or maintaining sleep and require further clinical investigation. However, most sleep deprivation occurs due to poor sleep quality and duration. The average adult requires 7-9h of sleep per night yet those with sleep deprivation will get less than 5-6h of sleep per night. Some people pride themselves on their ability to work with very little sleep yet sleep deprivation has been shown to affect human (and athletic) performance in a myriad of ways including:
- Impaired cognition effecting decision-making, judgment, mood, and reaction times
- Metabolic disruption including diabetes and obesity
- Weight gain to due craving more unhealthy and high carbohydrate foods and in larger portions
- Immunological resulting in increased proinflammatory cytokines which impair immune function and impede muscle recovery and repair from damage
- Cardiovascular dysfunction
- An increased risk of injury
There is also a dose-dependent relationship between sleep and performance; the greater the sleep loss the greater the performance loss, with performance loss occurring with as little as 2-4h of sleep loss. And for those who believe they are able to recoup the sleep they lose during the week on the weekends, the evidence says the contrary.
Improving Sleep Quality and Duration
The two sleep interventions that have received most research are sleep extension and sleep hygiene. Sleep extension and napping involves extra sleeping time to make sure the 7-9h daily limit is being met; this is especially useful when one knows they have a day of potential sleep deficit ahead. Sleep extension might involve going to sleep earlier or utilization day time naps that are more than 20 mins but less than 60 minutes and occur before 3pm. Sleep hygiene helps to improve sleep quality and duration and essentially involves a healthy sleep routine such as:
- Don't go to bed if you aren't sleepy
- Rise at the same time every morning, including on the weekends
- The bed is for sleeping only, don't watch TV or use electronic devices in bed
- Avoid caffeine after lunch
- Avoid alcohol, especially before bed
- Avoid high intensity interval training before bed
- Try to create a dark, quiet and cool space to sleep (ambient temperature is 19+/-2 degrees)
Improvements in sleep extension can lead to improved skill specific execution in sports, improved cognition including reaction times. mood, alertness and vigor. While improved sleep hygiene results in less fatigue and sleepiness.
Whether the goal is optimizing performance at work, in sport or about doing all you can to live a healthy life, sleep needs to be given as much attention as diet and exercise. By improving the quality and duration of sleep through better sleep hygiene and sleep extension one will yield benefits such as, reducing the risks of preventable disease like diabetes, obesity, cardiovascular disease, improved judgment and decision-making and optimized athletic performance and recovery.