We all need it, but rarely get enough of it; in today’s world, daily sound sleep has increasingly become a rare and precious commodity. Our busy lifestyles and work schedules, as well as the related increase in anxiety and other mental and physical health risks, all get in the way of regular good quality sleep at night.
Healthcare professionals underline that sufficient sound sleep daily is one of the three vital and interconnected pillars of good health, along with appropriate nutrition and regular physical exercise. Reducing or impairing one pillar can have profound impacts on the other two aspects of good health.
Over time, inadequate sleep raises your risk for chronic health problems, affects the heart and circulatory system, the body’s metabolism, respiratory system, and immune system, as well as impairs how well you think, react, work, learn, and get along with others. Lack of sufficient sleep has also been associated with a greater risk of developing type 2 diabetes and insulin resistance.
A meta-analysis of 36 studies covering over one million participants found that very short sleep of fewer than five hours and short sleep of fewer than six hours increased the risk of developing type 2 diabetes by 48 percent and 18 percent respectively. Sleep deprivation was also found to be associated with a higher risk of developing obesity, heart disease, and metabolic syndrome, all of which increase the risk of diabetes.
Mental health concerns, such as depression, are also strongly linked to poor sleep quality and sleeping disorders. One study among 2,672 participants found that those with anxiety and depression were more likely to report poorer sleep scores than those without anxiety and depression. In other studies, people with sleeping disorders like insomnia or obstructive sleep apnea also report higher rates of depression than those without.
Studies have shown that daily sleep cycles through two stages — Rapid Eye Movement (REM) sleep stage and non-REM sleep (NREM) — that are repeated every 80 to 100 minutes during the entire sleep process. Usually there are four to six cycles of NREM and REM per night, sometimes interrupted by brief waking up between the cycles. Researchers involved in sleep studies use sensors to record eye movements and brain activity to classify sleep phases and stages.
When you first fall asleep you enter the NREM sleep phase, with your blood pressure and heart rate both slowing down. During non-REM sleep, your parasympathetic system controls your body, and your heart does not work as hard as it does when you are awake. During the REM phase of sleep and when waking, your sympathetic system is activated, increasing your heart rate and blood pressure to the usual levels when you are awake and relaxed.
Non-REM sleep has three stages. The first stage is the transition between wakefulness and sleep. In the second stage, you are already asleep but not yet in deep sleep. Nearly half of our daily sleep time is spent in stage two NREM . In the third stage, called deep sleep or slow-wave sleep (because of the gentle wave pattern that appears in measurements of brain activity during this period) the body repairs injuries and reinforces the immune system. You need stage 3 NREM sleep to wake up feeling rested. Without enough stage 3 sleep, you feel tired and drained even if you slept for a long time.
There are two phases of REM sleep: phasic and tonic. Phasic REM sleep contains bursts of rapid eye movements, while tonic REM sleep does not. Phasic REM occurs about 90 minutes after you fall asleep, and is the primary ‘dreaming’ stage of sleep. It lasts roughly 10 minutes the first time, increasing with each REM cycle. The final cycle of stage R may last roughly between 30 to 60 minutes. During the phasic stage your eyes can be seen to twitch behind your eyelids and your brain activity is similar to your waking hours.
The patterns and types of sleep change as people mature. For example, newborns spend more time in REM sleep. The amount of slow-wave sleep peaks in early childhood and then drops sharply in the teenage years. Slow-wave sleep continues to decrease through adulthood, and older people may not have any slow-wave sleep at all.
Regularly sleeping less than seven hours at night for adults can put your health and safety at risk, which is why it is essential that you prioritize and protect your sleep on a daily basis. If all efforts to improve sleep on your own have failed, consultation with a sleep medicine expert to seek solutions is the next logical step. Most sleep disorders are treatable, with satisfactory outcomes.
