Sleeping when you’re injured or recovering sore muscles is similar to soaking up all the ZZZ’s when you have a fever or a cold. Unfortunately, for many athletes and people in the fitness community, injuries/recovery are not approached in the same way as sickness. For dedicated athletes and even the weekend-warrior, taking a break to recover can often be difficult either due to personal schedules, academic and work pressures or overtraining. We tell ourselves that we can push through it, that it’s all mental, that “I’ll rest later.” Eventually, we can permanently injure ourselves out of our sport/activity or stunt progress and growth. To avoid damage or improve both physical and mental success, anyone who strives to accomplish fitness goals either professionally or recreationally should prioritize their sleep and rest.
At night, you cycle through five sleep stages, oscillating between Non-REM (NREM) and Rapid Eye Movement (REM). NREM is composed of the first four stages; namely, they are referred to as NREM-1, NREM-2, NREM-3, and NREM-4. Deep or Slow-Wave (NREM-3/NREM-4) is characterized by slow, delta waves and is considered the most regenerative stage. REM sleep is the last stage and is distinguished by increased respiration, paralyzation, dreaming, and EEG waves similar to being awake. Regarding the connection between sleep and athletic performance and improvement, both NREM and REM sleep are principal in memory formation and consolidation, plasticity, and the process of recovery.
Sleep research has suggested that REM sleep plays a pivotal role in procedural memory, such as learning how to ride a bike, walk, or mastering certain athletic abilities, such as jumping hurdles. Moreover, as the night progresses, REM periods become longer. So, when you restrict your sleep you’re depriving yourself of potential REM and are making it harder for your body to master certain physical skills or movements, digressing your potential progress.
It is also hypothesized that NREM is crucial to both neural and physical recovery. NREM-3, in particular, is associated with the consolidation of motor memory and production of testosterone and growth hormones. Sleep deprivation may cause a stunt in the release of these hormones, impeding the process of muscle building and regeneration. Also, a handful of studies conducted on rats, cats and humans have seen an increase in NREM sleep post-high physical activity with a decrease in REM, further suggesting NREM is crucial for recovery post-exercise. As exertion increases, as does NREM slow-wave activity, insinuating your body knows which sleep will lead to better recovery. However, it is important to note that as the intensity of an activity progresses, wakefulness also increases; meaning, athletes should be even more attentive to make sure they get enough sleep.
The requirement for sleep is higher for athletes and practitioners of regular moderate to high-intensity exercise than non-active people. Young children often require more sleep (8-10 hours/night) compared to the average adult (7-8), due to growing. Similarly, athletes, as a result of increased physical stress in contrast to sedentary people, necessitate around the same hours of sleep as a growing child. However, when both student and professional athletes have been surveyed, there is a large percentage reporting they receive less-than-adequate sleep and deal with issues falling and staying asleep. It is highly likely that the pressures of day-to-day activity, school, work, and a push-till-you drop attitude placed on adults and students by coaches and society contribute to stunted sleep habits. Thus, impeding the maturation of the athletes’ full potential and functioning.
Coupled with ensuring your body and mind are recovering and strengthening after a hard workout there is evidence, although small, suggesting increased and optimized sleep improves athletic performance. In a small study measuring “the effects of sleep extension on athletic performance on collegiate basketball players,” sleeping or even resting in bed for 10 hours/night over six weeks lead to an increase in reaction times and a 9% growth in free-throw percentage. There is also data from studying mixed martial arts fighters and their sleep schedules to support keeping a consistent sleep schedule and incorporating rests throughout the day can improve performance and reduce injury. It is important to note that both of these studies also looked at taking rests throughout the day, not just sleeping. Their results suggest that just taking a break and relaxing can also increase performance and reduce injury.
Although sleep deprivation of 24 hours has not been shown to affect anaerobic exercise execution, prolonged privation beginning at 36 hours does begin to impair performance. This has been supported through studies done on weightlifters, runners, and MMA fighters. In addition to affecting the quality of exertion, reduced sleep quality and/or quantity impairs muscle glycogen repletion, muscle repair, and can reduce cognitive function.
One of an athlete’s or even a regularly active person’s biggest fears is an injury setting them back or putting them out of their activity permanently. Fortunately, regular, quality sleep may ensure that is less likely to happen. When Connecticut Children’s Medical Hospital examined the impact of sleep deprivation on injury in school in adolescent athletes they found hours of sleep and grade in school were the best predictors of possible injury. Students sleeping less than 8 hours were 1.7% more likely to have an injury and, for each subsequent year in school, they were 1.4% more likely to be injured. In addition to negatively affecting physical performance and safety, sleep privation can impede immune function, cognitive functioning, and psychomotor performance in both adolescents and adults. As students progress in school, they are burdened with additional academic, social and extra-curricular stress which correlates to a decrease in average hours in sleep. For adults, the pressures of work, life, or professional athleticism can also impair sleep. So, it’s imperative we make sure that we are properly resting our bodies and encourage young athletes to do the same to avoid damage.
At the end of the day, the most important thing athletes, or anyone, should do is listen to their bodies. If your body is exhausted and you can tell you need more sleep to function optimally, make sleep your priority and go to bed. There is no shame in resting your body, especially when it could mean you avoid an injury or even perform better in your sport. If you’re struggling to get to bed at night there are a few ways to make sure you do, such as limiting time on electronics before bed, setting up a regular sleep schedule, and optimizing your work and social load to be manageable while leaving room for sleeping optimally.
Often we let the numbers dictate how we should take care of our bodies instead of paying attention to how we feel. We pay more attention to how many calories we tracked, the steps we took, calories we burned, or how many hours our phone said we slept than what our bodies are telling us. Yes, sometimes technology can assist us in understanding how our bodies function, but your phone can’t tell you when you’re feeling burned out, tired, or if you’ve hurt yourself.
Recovery in athletics isn’t just about your foam roller or ice-bath. The most affordable, natural, and effective form of restoration is simply resting and sleeping. Our bodies are far more resilient than we make them appear. When we prioritize work, school, social activities, or training over their functioning, eventually, they will fail and put us back on the starting line, where we may never progress from again.
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