LISBETH HOYT, PT, DPT, CSCS.
It’s been a while since I’ve written about sleep… one of my favorite activities! In previous blogs we’ve talked about the importance of sleep for recovery and hormone regulation, but what exactly is sleep? And during times like these (global pandemic, uncertainty) how much does our sleep quality matter? Hint: it matters a lot.
Webster’s Dictionary defines sleep as the natural, easily reversible periodic state of many living things that are marked by the absence of wakefulness and by the loss of consciousness of one’s surroundings, is accompanied by a typical body posture (such as laying down with the eyes closed), the occurrence of dreaming, and changes in brain activity and physiological functioning. It is made up of cycles of non-REM sleep and REM sleep and is usually considered essential to the restoration and recovery of vital bodily and mental functions.
Even the definition of sleep is kind of a mouthful! So let’s break this down a bit. Sleep is made up of five stages: stages one through four and another called “REM” (rapid eye movements) that we cycle through multiple times a night. Scientists have found that a complete sleep cycle takes an average of 90-110 minutes. Each cycle has its own characteristic brain activity and physiological functioning. Stage 1, known as light sleep, it’s the early stage of sleep where you can be easily awakened. As you move into Stage 2 you fall deeper into sleep and your brain activity calms. REM sleep is when dreaming occurs and is characterized by rapid eye movements, higher heart rate, and higher blood pressure. Stages 3 and 4 are known as deep sleep and have slower brain waves called delta waves, with no eye movements or muscle activities. It’s usually very difficult to wake someone up from this stage of sleep, and if you do, they tend to be groggy and disoriented. These two stages are extremely important to our overall health and functional abilities.
When you’re in deep sleep, your body undergoes changes that are important for daily function. The growth hormone is released during the deep sleep stages which helps your body physically recover from exercise stress and illness. The parts of your brain that control emotions, decision making, and social interactions are significantly quieted during this stage. This is thought to help maintain optimal social and emotional functioning when you are awake. Your brain also consolidates memories while in deep sleep, which improves overall learning and memory recall during the day. If you aren’t sleeping enough or your sleep quality is poor, your body spends the next day or two suffering.
Adults are recommended seven to nine hours of sleep per night, and that means sleeping… not time in bed! Numerous things can interfere with good sleep quality including times of high stress (hello 2020) to that 3:00 am construction outside your window. The more nights in a row you have poor sleep quality, the longer your body is trying to make up for the deprivation. A few sleepless nights can leave you cranky and easily irritated, but continued poor sleep quality can lead to more serious things like increased risk of illness or injury.
Just like in training, quality is more important than quantity when it comes to sleep, especially now. Try spending a week observing your sleep habits. Are you on your phone right up until lights out? Having trouble falling asleep because you can’t turn off your brain? Is this having an impact on how you feel the next day? There may be small changes you can make to your routine for improvements. And if you’re having trouble figuring it out alone, we’re here to help!
Dictionary by Merriam-Webster: America’s most-trusted online dictionary. (n.d.). Retrieved October 08, 2020, from https://www.merriam-webster.com/
ASA Authors & ReviewersSleep Physician at American Sleep Association Reviewers and WritersBoard-certified sleep M.D. physicians, A. (n.d.). What is Sleep and Why is It Important? Retrieved October 08, 2020, from https://www.sleepassociation.org/about-sleep/what-is-sleep/