Sleep: A Tool in Our Toolbox
“Sleep quality and duration should be considered a vital sign, as they are strong indicators of overall health and quality of life,” said Kristen Knutson PhD, National Sleep Foundation Sleep in America™ Poll Scholar.
Everyone knows that they should probably be sleeping more, but have you ever thought about the biological purpose that sleep serves? Outlined below are a few of the reasons our bodies need sleep, that will hopefully encourage you to get more Zzz’s.
The body is a machine and all machines need maintenance. A car cannot run indefinitely without running the risk of overheating, breaking down, or at the very least, shortening the lifespan of the car. Similarly, humans cannot function optimally without “maintenance” in the form of sleep (~7-9 hours per night).
Throughout the day, the body expends energy and at night that energy is used to help rebuild the body. Sleep helps our bodies use the food we consumed throughout the day to replenish glycogen stores in the muscle and liver. Sleep also gives our brains time to reset. During waking hours, our brains may use up to 25% of the body’s energy, so restful sleep gives the brain “time off” to conserve energy for activities of the following day.
Throughout the day, our body uses energy to drive brain activity, exercise, and metabolic processes. At night, our body uses this energy to repair, rebuild, and restore. The body has to restore materials that were used up during waking hours, such as proteins. Exercise causes microtears in our muscles that need to be repaired in order to build muscle mass. This is especially important for athletes because they break down additional proteins that have to be replenished in order to actually build muscle. Thus, if you are depriving yourself of sleep, you’re essentially depriving yourself of the “gains” you work so hard for in the gym.
The restorative nature of sleep is especially important for youth and adolescent athletes, as growth hormone is released during sleep. Growth hormone is one of the key players in muscle hypertrophy, even in adults. For adolescent and youth athletes, growth hormone plays an even greater role in growth beyond the point of muscle hypertrophy. While their muscles have to rebuild following breakdown from their sport or resistance training, youth and teens are also still growing height, weight, brain, and bone wise.
Lack of sleep interferes with growth hormone release which can stunt growth in adolescents or lead to injury, in both adolescents and active adults. Injuries could be due to insufficient growth hormone release, and thus inadequate bone growth or muscle repair. Injury could also be due to decreased reaction times, another side effect of sleep deprivation because the brain did not recover as much as it needed to.
Just as adequate sleep allows for sufficient growth hormone release, sleep deprivation can cause elevated cortisol levels. Cortisol is commonly known as the “stress hormone.” Cortisol levels fluctuate on a 24 hour cycle, just as our circadian rhythms do. If our sleep is out of whack, our cortisol levels will also be out of whack and vice versa. While cortisol is necessary in sufficient amounts, excess cortisol has a catabolic effect. This means that it is breaking down instead of building up, not a desirable effect in terms of strength training or rehabilitation in which the goal is to build muscle.
Sleeping between bouts of learning and recall has been shown to improve retention. This is important not only for students, but for any human being. Don’t we all strive to learn something new every day? What about remembering how to do the exercises your P.T. prescribed in a session two weeks ago?
Sleep affects our learning of complicated motor skills and declarative memory tasks. Complicated motor skills include learning technical lifts like the snatch and clean and jerk. While we know sleep is important for rebuilding the muscles that were broken down during that lift, sleep is also vital for our body to forge the neural pathway of how to do that lift or skill. Declarative memory tasks involve recalling facts or statements. Isn’t it frustrating when you can’t recall what someone told you just yesterday or can’t remember the name of a person you’ve met two times?
Sleep and Appetite
Know that your appetite may be altered following nights when you do not get adequate sleep. Two hormones: ghrelin (appetite stimulant) and leptin (appetite suppressant) are involved in hunger regulation and are affected by sleep deprivation. If you sleep too little, ghrelin increases and leptin decreases, heightening your hunger cues.
In addition to elevated ghrelin levels, a blood lipid called endocannabinoid also increases when you do not sleep enough. Endocannabinoid acts on the brain in a way that causes you to crave fatty, sugary foods, especially in the evenings.
While sleep deprivation causes altered hunger cues due to hormonal fluctuations, there is also the simple fact that the less hours you spend in bed, the more hours of the day you will probably spend in front of the fridge or pantry. The more time you’re awake, the more time you will most likely spend eating, and this can lead to weight gain.
Get your Zzz’s
At Prime, we talk about the “toolbox” we have for rehabilitation and optimization of daily living. Sleep is one of the most vital tools we have in the toolbox, and should be capitalized upon because of its effect on memory, energy and appetite levels, and muscle rebuilding.
Instead of beating yourself up for not getting enough sleep, try to view sleep as an exciting tool that can help you reach your goals. Now turn off your phone and take a 20 minute power nap or get those 7-9 hours!
If you'd like to learn more about sleep or how we manage patients who are having trouble sleeping, reach out to us today by emailing firstname.lastname@example.org! We would love to help you get out of pain and get back to doing the things you love to do!