Most of us have heard that we “need to get our eight hours of sleep” every night, but do the hours of sleep matter as much as the quality of sleep you receive? According to Asim Maqsood, MD, a sleep medicine specialist with SSM Health St. Anthony Hospital in Oklahoma, sleep quality definitely matters.
“Deep sleep matters, as it is the stage of sleep where our body repairs tissues and muscles, recharges our immune system, processes and consolidate memories, releases growth hormone and clears brain waste,” Maqsood said.
He went on to explain that sleep can be divided into two basic categories – rapid eye movement sleep (REM) and non-rapid eye movement sleep (NREM). On average, for an otherwise healthy young adult, 70 to 75% of sleep is NREM and 20 to 25% is REM.
REM sleep is generally the dreaming phase where the brain is active as if someone is awake and eyes may move rapidly under the lids, but the body is sleeping (to avoid acting out on dreams). This stage generally occurs in the later third of the night and helps with emotional processing, learning and memory.
NREM sleep includes superficial sleep and deep sleep, which Maqsood said is the most restorative time of sleep and is vital for immune system, muscle repair and memory consolidation. Furthermore, he explained, deep sleep promotes production of cytokines (proteins to help fight infection and inflammation). T cells (which identify and destroy infected cells) become more active during deep sleep and the body builds antibodies against infections.
“During sleep deprivation, cytokine levels drop, weakening the immune system,” Maqsood said. “Studies have shown people who consistently get poor and insufficient sleep are more susceptible to getting colds, take longer to recover from viruses and have a low response to vaccines.”
Adenosine TriPhosphate (ATP) is the main energy molecule used by muscles, brain and other organs to function during the day and when we sleep, deep sleep restores and replenishes ATP levels, Maqsood explained.
“Our sympathetic nervous system, which we use to deal with all sorts of stress, powers down during deep sleep and our parasympathetic nervous system takes over. This helps lowers blood pressure, heart rate and also slows down metabolism and resets our stress-response system. It also regulates key hormones involved in energy use like insulin, cortisol, leptin and ghrelin which helps to restore energy. Our muscles and tissues rest and restore strength and energy. Our brain energy also resets as metabolic waste from the brain gets cleared and helps with mental fatigue, focus, motivation and mood.”
So how does a person achieve the deep sleep its body needs?
Maqsood said that having a regular sleep/wake schedule improves the quality and depth of sleep by strengthening the circadian rhythm, promoting consistent melatonin release, improving overall architecture of sleep and reducing the fragmentation of the sleep.
“Optimization of the sleep environment can significantly support deep sleep, as it would help to minimize awakening and promotes physiological conditions that help the brain to enter and maintain deep sleep more effectively,” he said.
For the best chance at sleep quality success, Maqsood said a person should stick to a regular sleep/wake schedule, keep the room dark, comfortably cold and quiet environment, avoid screen time before and in the bed, limit caffeine after mid-afternoon, exercise regularly and manage stress effectively.
Some health issues can affect your ability to get great restorative sleep. If you are concerned, talk to your primary care doctor about seeing a sleep specialist and/or having a sleep study.
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