Sleep is the ultimate reboot for your body and brain. It’s clear that we need a gentle slumber for health reasons, both physical and mental, but there’s still a lot we don’t know about what happens when we slip into a restful sleep. At the simplest level, we know that for hours every night, our bodies become unconscious and our mind is unaware of what’s going on around us. Instead, we venture into a blissful dream state.
Despite the lack of visible activity, science suggests there’s a lot going on in this state of unconsciousness. As we lie in an unconscious state, bodily processes slow, but our brains are still active. Some experts believe one of the main purposes of sleep is to consolidate memories we form throughout the day, to solidify them, in a sense.
Yet, sleep is more than just a mental reboot, it has a far-reaching impact on health and longevity. Studies show that getting too little sleep is linked with a higher risk of cardiovascular disease, type 2 diabetes, and overall mortality. Skimping on sleep also suppresses the immune system’s ability to protect against a host of invaders. Lack of sleep may even shorten lifespan. A 2010 study of older women found that those who get less than 5 hours of sleep per night had a higher death rate than those who got 6+ hours nightly.
Competitive athletes need sleep as well. A good night’s sleep gives an athlete the mental and physical edge they need to compete safely and effectively. The same applies if you work out. If you’ve had a good night’s sleep, you’ll have more energy and focus, so you can focus to execute the moves properly and get the most out of your sweat session.
But, what about the risk of injury? Studies show that people who are sleep deprived are more likely to get involved in a car accident. Skimping on sleep increases the odds of suffering an exercise training injury as well.
Lack of Sleep and Training Injuries
It appears that reduced sleep increases the risk of exercise-related injuries. For example, a study of teenage athletes found that lack of sufficient sleep boosts the frequency of sports injuries. In fact, one study that looked at adolescent athletes found that those who slept 8 or more hours per night were 68% less likely to sustain a sports-related injury.
Although it’s not clear exactly how being sleep deprived increases injury risk, a theory is that it interferes with proprioception, the knowledge of where your body is in space. If your proprioception is off even slightly, it can lead to missteps that result in injury. Lack of good proprioception is what causes many elderly people to fall, for example, when they get up to go to the bathroom at night. You need that input from your brain to your muscles, and lack of sleep can disrupt it.
What’s more, insufficient sleep from staying up late to watch television or do computer work, impacts decision making and slows reaction time the next day. It’s not hard to see how this would adversely impact performance in a variety of sports and exercises as well as increase the risk of injury. In fact, lack of sleep can lead to poor decision making and delayed reactions in a variety of situations. For example, investigations exposed the fact that the meltdown of the Chernobyl nuclear power plant and the explosion and destruction of the Challenger space shuttle were both partially due to poor sleep impacting the ability to make a sound decision. Studies show that lack of sleep short-circuits brain connections you need to make smart decisions. This applies to exercise training too!
Sleep and Muscle Repair
Don’t forget that your muscles repair between strength-training sessions and you need sleep to do that. Skimping on sleep elevates cortisol, a catabolic hormone that causes muscle breakdown, thereby jeopardizing your hard-earned muscle. So, insufficient sleep doesn’t just increase the risk of injury, it makes it harder to get the full benefits of your strength-training sessions. Plus, studies show inadequate sleep reigns in muscle protein synthesis, thereby interfering with muscle recovery after training or after an injury. We need protein for muscle repair – but also sleep!
How Much Do You Need?
Most studies suggest that 7 to 7.5 hours nightly is about the right amount of sleep for the average person. But, if you’re very physically active and train hard, you may need a bit more – around 8 hours. A good barometer of whether you’re getting enough is how you feel. Do you feel refreshed during the day or do you have to grab extra cups of coffee to stay productive? We each have slightly different sleep requirements based on lifestyle and genetics.
To optimize sleep, stop using electronic devices an hour before turning in – and keep those devices out of your bedroom. A 2011 study carried out by the National Sleep Foundation found that people who use their devices within 60 minutes of sleep time have more problems falling asleep. Also, turn down the temperature of your bedroom to between 60 and 67 degrees F. Studies show that a lower bedroom temperature helps bring on sleep.
The Bottom Line
You need sleep to maximize muscle repair and growth after a workout, but also to make your training more effective and to lower your risk of injury. So, along with nutrition and the appropriate exercises, prioritize sleep. It matters!
ScienceDaily.com. “High risk of injury in young elite athletes”
Health.com. “11 Surprising Health Benefits of Sleep”
NIH National Heart, Lung, and Blood Institute. “Sleep Deprivation and Deficiency”
Med Hypotheses. 2011 Aug;77(2):220-2. doi: 10.1016/j.mehy.2011.04.017. Epub 2011 May 7.
British Journal of Sports Medicine blog. “Sleep for health and sports performance”
Research Gate. “Chronic Lack of Sleep is Associated With Increased Sports Injuries in Adolescent Athletes”
Barrington220.org. “Effect of Sleep on Sports Performance and Sports Injury”
Psychology Today. “How Do Sleeplessness and Insomnia Sabotage Decision Making?”
Sleep Medicine. Volume 14, Supplement 1, December 2013, Page e262.
National Sleep Foundation. “How Much Sleep Do We Really Need?”
National Sleep Foundation. “Electronics in the Bedroom”
Sleep.org. “The Ideal Temperature for Sleep”