Do you ever wake up and have your morning coffee and suddenly ponder why you may be tired? It’s likely that the cup of coffee you had won’t make up for the fact that you had less sleep than the recommended seven hours a night for people aged 18-65 years old. At first glance, a few nights without a lot of sleep may not seem overly detrimental to your overall health, but it can definitely become a larger issue when you chronically lack sleep or if you have insomnia or other sleep disorders such as sleep apnea, where your breathing starts and stops at night.
Cardiovascular disease, aka heart disease is the leading cause of death worldwide and the 2nd leading cause of death in Canada [1], [2]. Sleep plays an important role in cardiovascular disease and is recognized by the American Heart Association as a core health behaviour that is an important component in cardiovascular health. A lot of the distractions or stressors in our life contribute to our quality and lack of sleep, such as pressures from work and the amount of screen time spent scrolling on Instagram or watching Tiktok videos.
Your autonomic nervous system is composed of the sympathetic system (fight or flight) and parasympathetic system (rest and digest). Dysregulation of the autonomic system in individuals with insomnia has been associated with sleep disturbance-associated cardiovascular disease. Particularly, it is the increase in the sympathetic tone and decrease in the parasympathetic tone leading to an increase in cardiovascular risk. Studies have shown that individuals with short sleep (routinely sleeping less than six hours a day) and a disrupted circadian rhythm had decreased heart rate variability, increased sympathetic and decreased parasympathetic cardiac tone [3].
Another measure used to reflect autonomic function is systolic blood pressure (this is when your heart is contracting). Typically when we sleep, our systolic blood pressure decreases by roughly 10%. Individuals with chronic insomnia don’t experience much of a dip and have an overall higher 24 systolic blood pressure relative to individuals who get good sleep. The lack of dip in systolic blood pressure may be associated with cardiovascular risk.
Short sleep, difficulty initiating sleep, and difficulty maintaining sleep have contributed to an increased risk of cardiovascular events such as a heart attack, especially in those with coronary artery disease (CAD). There are also linkages between short sleep and irregular heart rhythms, such as atrial fibrillation.
Studies have shown that experiments that limit the sleep of individuals resulted in hormonal imbalances, increased insulin resistance, and increases in appetite due to the increase in the appetite stimulating hormone, Ghrelin. Multiple meta-analyses with self-reported short sleep have been associated with an increased risk of metabolic syndrome.
Overall, literature has shown that short sleep and insomnia over a short period of time affect your autonomic nervous system, whereas chronic lack of sleep can lead to more serious conditions, such as metabolic syndrome and coronary artery disease.
With the pandemic and ongoing current events, it may be difficult to maintain a sleep schedule. However, it would be a good idea to attempt maintaining a routine sleep schedule that is consistent but also works best for you.
In addition, if you’re experiencing odd dreams during quarantine, and if you would like to read about other people’s quarantine dreams or submit an odd quarantine dream of you own: https://www.idreamofcovid.com/dreams.
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