Do you recall how you felt the last time you missed a good night's sleep? Maybe you felt like you had no energy. Maybe you were irritable. Perhaps you had difficulty focusing. Well, those among others are signs of sleep deprivation that you probably shouldn’t ignore because sleep is a basic physiological need and a crucial component of human life. It serves a number of restorative functions in your body and brain and it has been shown to improve memory recall, regulate metabolism, decrease mental fatigue, and play a massive role in muscle repair. Sleep also impacts the regulation of your homeostasis and your immune inflammatory responses and helps remove wastes and byproducts that build up while you’re awake.
So what can we do to reduce sleep deprivation and ensure healthier physical functions?
For starters, we need to have a basic understanding of how sleep affects us to maximize our physical, mental and overall health.
Sleep and Circadian rhythm
Decades of studies have demonstrated the positive impact of sleep on our health and survival. Our bodies operate, in part, through a biological clock referred to as the “circadian rhythm” that regulates our physical, mental and behavioral changes and heavily influences vital functions such as hormone release, eating habits, digestion and homeostasis. Long term circadian rhythm disturbance is associated with comorbidities and chronic illnesses such as cardiovascular and metabolic diseases, Alzheimer’s and more. Lack of sleep can throw off a person’s circadian rhythm, making it difficult to produce the proper hormones necessary to carry out daily functions.
Sleep deprivation, weight and overall health
Is insufficient sleep contributing to your weight gain? It just might be!
The association of lack of sleep and having an increased risk of being overweight, increased appetite and slowed metabolism has been widely researched. Lack of sleep is related to sedentary behavior that can lead to cognitive decline, tobacco use, uncontrolled food intake, and increased BMI which collectively induce a cascade of health complications.
It is estimated that more than one-third of Americans are not meeting their sleep recommendations, experiencing insomnia or sleep disturbances which reduce overall sleep quality and efficiency. Inefficient sleep can compromise your health by increasing the risk of cardiovascular diseases, stroke, depression and anxiety. In addition, it can influence productivity at work and may lead to life threatening events.
Practicing sleep hygiene is essential in improving one’s sleep, this includes going to bed at approximately the same time every night, sleeping in a cool, dark, quiet room, and removing all electronic devices that emit blue light and can negatively impact one’s quality of sleep by disturbing the circadian rhythm.
Sleep and hormonal changes
Additionally, the absence of sleep has a big impact on hormones, especially those that are responsible for muscle repair. Low quality sleep promotes the secretion of the hormones that break down muscles (i.e cortisol and corticosterone) while suppressing the secretion of the hormones that help build muscles and gain strength (i.e growth hormone and testosterone). This results in the establishment of a muscle breakdown environment which is the opposite of what we want.
In addition, the disruption of melatonin (the sleep hormone) synthesis occurs when there is exposure to light since melatonin is produced in darkness. Melatonin contributes to synchronizing the sleep-wake cycle and other diverse physiological processes that include circadian rhythms, reproduction, temperature regulation and immune responses.
Sleep deprivation and disturbances do not only occur with sleep difficulties but can also be caused by physical pain such as lower back pain or joint pain which is a highly common issue within the general population.
Scientists have linked endocrine or hormonal conditions to the disruption of sleep and circadian rhythm. Insulin’s sensitivity (how efficiently your body responds to insulin) is widely affected by lack of sleep. In the long term this can lead to insulin resistance where your body does not respond to the insulin hormone. This may ultimately lead to elevated blood sugar, putting you in an extremely vulnerable health status. Another metabolic hormone whose function is impeded by sleep deprivation is Leptin.
Leptin is also known as the satiety hormone and it signals the brain to stop eating. This hormone is responsible for inhibiting hunger and regulating energy balance by preventing the body from triggering hunger responses when it doesn’t need energy. Similar to insulin, prolonged sleep deprivation and obesity lead to leptin resistance, a condition in which the body stops responding to leptin so the person is unable to feel satiated and is constantly hungry. Despite leptin being understudied, its resistance is now believed to be the leading cause of fat gain in humans.
Exercise and Sleep
Exercise and sleep impact one another reciprocally. Exercise has been widely used as a potential complementary or an alternative approach to enhance quality, duration and latency of sleep. Sleep debt reduces the activity of protein build up and promotes the protein degradation pathways which favor the breakdown and loss of lean muscle mass and thus can hinder muscle recovery and growth.
Growth Hormone is another hormone that stands out. It has many functions and vital roles to our physiology such as a healthier body composition, turnover of muscle bone and collagen, and improved metabolism. Luckily for us, the most powerful and non-pharmaceutical stimulus for this hormone is exercise and sleep. This highlights the importance and interchangeable role of these two components’ and their contribution to one’s health and longevity.
While research is limited on how weight training exactly improves sleep, we know that exercise increases the amount of slow sleep we get. Slow sleep refers to deep sleep, where the brain and body get the most opportunity to recover and it’s crucial for maintaining cognitive and physical health.
According to the international sport medicine journal, a single bout of strength or endurance training enhanced different parameters related to sleep patterns and the positive effects were specifically evident during the first night's sleep following exercise.
Moderate to vigorous exercise in particular helps you sleep better. Additionally, you can improve your sleep quality by lowering your “sleep onset,” or the time it takes for you to fall asleep.
In the 2013 sleep in America poll, several adults between the age of 23-60 took a survey on “exercise and sleep” in which roughly 75-83% of the respondents who regularly participate in moderate to high intensity exercise reported very good quality of sleep. On the contrary, only 50% of those who didn’t exercise reported good sleep.
Exercise, sleep and stress
We all experience stress from time to time whether it comes from a stressful job, studies or family obligations. Stress and sleep in fact have a bidirectional relationship. On one hand when you are under stress you are in survival mode or under threat. Our basic instincts tell us we are not supposed to sleep deeply and sufficiently as a basic survival mechanism, hence the lack of quality sleep you experience when you are stressed.
On the other hand, lack of sleep or sleep disturbances that are not related to stress also increase stress. For example, joint pain or back pain reduces quality of sleep and therefore contributes to elevated stress.
However, when we experience chronic stress that causes us sleep disturbances or even restless sleep for a prolonged period, that, my friends, is dangerous for our mental and physical health.
Sleep regulates our stress hormones and maintains the health and integrity of your nervous system, immune system, endocrine system etc. Insufficient sleep hinders our body’s ability to regulate stress hormones leading to several unhealthy markers such as high blood pressure and uncontrollable blood glucose levels, depression, anxiety and cardiovascular diseases while lowering life expectancy.
Exercise decreases your stress and increases your sense of well being. Exercise directly affects how you feel; it causes your body to pump the brain’s “feel good” neurotransmitters AKA endorphins.
To sum it all up, there is a massive hidden cost that accompanies disturbed sleep patterns which people tend to overlook. Luckily, researchers and health experts have started to identify the connections between sleep deprivation, sedentary behaviors and diseases indicating that a good quality sleep is just as important to health and wellbeing as a nutrition and exercise. In fact, those affect each other interchangeably because exercise and nutrition reduce stress and promote better sleep, which in return lead to better recovery, performance and energy balance.
Health organisations such as WHO, CDC, AASM and SRS recommend 7 or more hours of sleep for adults between the age of 18 and 60 years old. Besides sleep duration, sleep quality matters just as much. Sleep quality is assessed through sleep latency, sleep waking, sleep efficiency and wakefulness or how often you wake up and for how long. These can be improved by adopting sleep hygiene habits, ensuring proper nutrition and regularly engaging in exercise.
– Dina Al-Rubaye, BS, MA, CPT
References:
U.S. Department of Health and Human Services. (n.d.). Circadian rhythms. National Institute of General Medical Sciences. Retrieved November 22, 2021, from https://www.nigms.nih.gov/education/fact-sheets/Pages/circadian-rhythms.aspx.
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