Why Sleep Is Important for Health and Athletic Performance

Sleep is a biological process that allows your body and brain to recover, regulate hormones and consolidate memories. The benefits of sleep directly affect athletic performance, mood and long-term health. But while many people have a baseline knowledge of the importance of sleep, exactly why sleep is important and how much sleep athletes need is more complicated.

If you're looking for a recovery edge beyond adjusting your nutritional macros and deep-tissue massage, it's important to take a closer look at your sleep habits. Here’s why.

• Sleep is a crucial element of recovery.
• The body performs important repair work while you sleep.
• The amount of sleep each person needs is individual.

A research review published in the 2019 issue of the International Journal of Sports Medicine noted that sleep is critical to overall health, and that includes athletic performance. Researchers suggested that sleep deprivation could lead to reduced reaction time, less strength and endurance, and even lower mood and less energy.

Another analysis, published as a consensus statement from sports medicine experts in a 2021 issue of the British Journal of Sports Medicine, noted that elite athletes are particularly susceptible to sleep shortfalls, including getting too little sleep in general and having disrupted sleep when they do manage to get some shut-eye, due to factors such as travel, competition start times and injuries. The authors of the paper added that previous research on a wider population, not just athletes, showed that poor sleep is associated with other health risks, including a higher risk of respiratory infection and heart issues.

For example, a study in a 2022 issue of the Journal of the American Heart Association concluded that too little—and also too much—sleep, as well as poor sleep patterns, are linked to an increased risk of cardiovascular disease. Other studies have suggested that sleep quality influences a range of other factors, including immune system response, the ability to regulate blood sugar effectively and the chances that you'll have good gut health.

All of these can contribute to how well you recover from a workout, said Chris Winter, MD and president of Charlottesville Neurology and Sleep Medicine. That doesn't just mean how refreshed you feel the next time you exercise, but how boosted you seem in other ways as well, including mental and physical energy.

"It's not just a matter of getting a good night's sleep and then you perform better the next day", he said. "While that might be the case, sleep quality could be affecting you in more ways than you realise, and that informs not just your training recovery, but possibly nearly every other aspect of your health as well".

"When you sleep, and especially when you're in deep sleep, the body performs repair work that can't be done when you're active", Winter said. For example, he noted that your pituitary gland releases growth hormone, used to build new muscle fibers and fix damaged muscle tissue. This is why you may hear health experts and personal trainers say you can't increase muscle size and strength through training alone. Instead, muscles get stronger from being repaired after a workout.

Without adequate recovery, that process will fall short, and you may end up with more muscle damage and inflammation due to overtraining.

"Another important aspect of recovery is stress reduction", Winter said. Exercise produces a certain level of physical and mental stress. De-stressing tactics done during the day are helpful, but the central nervous system, or CNS, achieves its highest level of "chilling out" through sleep, he said. In other words, a good night's rest acts as a reset for the CNS and reduces the potentially negative effects of chronic stress, Winter said.

A 2020 meta-analysis of 73 studies published in Sleep Medicine Reviews also discovered that getting less sleep than is recommended is linked with a 55 percent increase in mood issues, like feelings of anger, depression and anxiety. "Sleep is a universal and modifiable risk factor for preventing mood deficits", the researchers wrote in the conclusion.

Although sleep can aid recovery and improve overall athletic performance, it isn't a one-way relationship. Research indicates that regular exercise, such as strength training, can result in improved sleep quality.

Implementing strength training into your weekly routine can create a beneficial cycle, according to sleep and exercise researcher Jason Bennie, Ph.D., and associate professor in physical activity epidemiology at the University of Southern Queensland in Australia. In other words, consistent exercise improves sleep, and better sleep improves exercise, creating a mutually advantageous relationship that builds on each other.

For example, Bennie was the lead author on a study of more than 23,000 adults, which was published in a 2020 issue of Preventive Medicine Reports, and found any degree of resistance training (whatever the frequency or intensity) boosted sleep quality—even for those with a history of insomnia. A notable aspect of that research, Bennie said, was the range of participants, which included both men and women, ages 18 to those over 65.

"Considering the large population sample we used, there's compelling evidence that this connection is true for everyone, no matter who you are or how old you are", Bennie said. The reasons likely include better heart rate variability and blood pressure, as well as optimised glucose and cholesterol regulation, all of which have been shown to benefit from quality sleep and regular exercise. Of course, it's always a good idea to check in with your doctor or trainer before starting a new exercise programme.

Given the evidence that sleep is a boon to performance and recovery, the question becomes, "How much sleep do you need to see a difference?" Similar to the question, “"How much water should you drink every day?" the answer seems to be: It depends.

The Centers for Disease Control and Prevention (CDC) offers age-based guidance:

• School-aged kids (6 to 12): 9 to 12 hours
• Teens (13 to 17): 9 to 10 hours
• Adults: 7 or more hours

For athletes, the ideal amount of sleep depends on factors such as the type of exercise you do, how intense it is and your individual sleep needs. However, athletes tend to need more sleep than the average person. A study of 175 elite athletes published in the International Journal of Sports Physiology and Performance found that most athletes said they needed 8.3 hours of sleep to feel rested. (However, many fell short of that by an hour or more.)

But Winter said the CDC guidance is not as foundational as it appears. "What tends to matter more is the total amount you get per week," he said. "That means you can play around a little bit from night to night, not by a huge degree but enough that you shouldn't feel like staying up late one evening is going to sabotage you for days to come".

That weekly total should be consistent, he added, and will usually total about 50 to 60 hours of sleep. "If you need to throw in a few naps to get that total up, for example, that's likely a good idea as long as that's an occasional strategy rather than a daily need", Winter said.

There really isn't a one-sleep-fits-all approach, which means most people should experiment with different sleep durations, bedtimes and wake times to find what works best for them. That includes:

• Taking your needs into account, including training intensity and recovery requirements.
• Keeping sleep and training logs. Winter recommends recording variables such as duration of training sessions, bedtime, perception of sleep quality, whether you woke up refreshed or groggy, and energy levels throughout the day—but especially on days you exercise.

Identifying patterns can help to refine how much sleep you need, and then hone in on consistency. "Sometimes, just being more aware of the sleep-exercise-recovery connection is enough to take meaningful steps towards better habits", he said.

Beyond that, it's important to follow basic sleep hygiene recommendations, including:

• Try to keep a consistent sleep and wake time.
• Keep your bedroom quiet and cool.
• Turn off electronic devices at least 30 minutes before bed.
• Avoid large meals and alcohol before bed.
• Skip caffeine in the afternoon or evening.
• Exercise regularly.
• Keep a healthy diet.