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World Sleep Day: How sleep impacts your mind and body

The right quantity and quality of sleep can help ward off disease, health complications and mental health disorders

Sleep deprivation leaves the body prone to inflammation and injuries, unexplained pains, inflamed joints, sore muscles and brain fog
Sleep deprivation leaves the body prone to inflammation and injuries, unexplained pains, inflamed joints, sore muscles and brain fog (iStockphoto)

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If you are having trouble falling asleep thinking about your training the next day, this is the perfect reading material for you. Sleep, or lack of it, has the power to determine how much benefit you can reap from an active lifestyle and have a profound impact on health. Sleep is so intricately related to physical and mental health, emotional well-being and cognition that the theme for this year’s World Sleep Day (17 March) was “Sleep is Essential for Health.”

The human body is designed to be in sync with the circadian rhythm and it works optimally if we abide by the rules of nature, says Gagan Arora, a Delhi-based celebrity trainer and founder of Kosmic Fitness, a studio in Delhi. “Modern life brought with it the ability and mobility to travel fast, gadgets and many other things in the name of development, which have disrupted the human circadian rhythm,” says Arora.

Also read: The ultimate guide to sleeping better

The sleep-exercise relationship is quite like the chicken-and-egg conundrum: Exercise helps you sleep better and sleep helps you exercise better. But it is better to think of it as an integrated relationship between the mind and body. “Inadequate sleep can cause lack of stamina and energy, making it difficult to exercise. Proper and sufficient sleep is important to provide the energy required for exercising. At the same time, exercising can improve sleep quality,” explains Shama Kovale, ENT consultant at the Kokilaben Dhirubhai Ambani Hospital in Mumbai.

It is while we are sleeping that our body and brain repair themselves. The muscles heal from the day’s wear and tear and workload. Our cardiac, respiratory, gastrointestinal, musculoskeletal and nervous systems slow down and reset. Deep sleep lets the body’s cells and tissues recover from the day’s labours. Tissue repair, muscle growth and protein synthesis are possible only while we are sleeping When you rest, you are basically sending a signal to your body to relax, allowing it to conserve energy and repair itself, say sleep and fitness experts. After all, most humans spend about one-third of their lives sleeping, points out Ashish Kumar Prakash, respiratory and sleep medicine consultant at the Medanta Hospital in Gurugram, Haryana.

“When we are born, we spend nearly 22 hours of our day sleeping. As we grow up, we need only six-eight hours of sleep to function properly,” adds Dr Prakash. However, if the physical demands on you through the day are high, you must get a full eight-nine hours, adds Arora.

Even if you only get the minimal six hours of sleep, over 20% of it should be deep sleep or stage 4 sleep, also known as the REM (rapid eye movement) stage, so that you wake up refreshed, explains Dr Prakash. A healthy sleep cycle helps the body produce the hormones melatonin and prolactin, which have been found to improve good bacteria in the intestines and help digestion.

Sleep deprivation leaves the body prone to inflammation and injuries, unexplained pains, inflamed joints, sore muscles and brain fog, says Arora. “One loses the ability to gain strength and starts accumulating more fat. Workout sessions done without adequate sleep do more harm than good: It becomes harder for the body to cope with the higher intensity that one subjects it to while training harder or playing a sport to get fitter and into the desired body fat ranges. In extreme cases, it could also lead to chronic illness, strokes and heart attacks,” warns Arora.

After all, it isn’t just the quantity, but also the quality, of sleep that matters. A study presented at an American College of Cardiology conference on 6 March identified five factors that are indicators of the quality of sleep: ideal sleep duration of seven-eight hours a night; difficulty in falling asleep no more than two times a week; trouble staying asleep no more than two times a week; not using any sleep medication; and feeling well rested after waking up at least five days a week.

For this study, researchers analysed data from 172,321 people in the US with an average age of 50 (54% of the respondents were women), with a median follow-up of 4.3 years. People who experienced all five indicators of sleep quality during their shuteye were 30% less likely to die of any health complication or disease, 21% less likely to die of cardiovascular disease, had a 19% lower chance of death due to cancer, and 40% lower risk of death due to other assorted reasons. The researchers estimated these gains in life expectancy starting at the age of 30.

“If people have all these ideal sleep behaviours, they are more likely to live longer,” said Frank Qian, co-writer of the study. “So, if we can improve sleep overall, and identifying sleep disorders is especially important, we may be able to prevent some of this premature mortality.”

Also read: Sleep tourism: why are people going on vacations to sleep?

Sleep problems can lead to cardiovascular complications, for without adequate and proper sleep, our heart and pulse rates tend to increase, breathing becomes irregular and we become susceptible to pulmonary artery hypertension. “It raises the chances of developing health issues such as diabetes, high blood pressure, heart disease and stroke. Also, those who do not get enough sleep tend to consume more food, especially high-carbohydrate and high-calorie foods, leading to weight gain and lifestyle diseases, as well as sleep disorders such as sleep apnea and restless leg syndrome,” says Dr Kovale.

Dr Kovale’s claim is backed up by evidence. Studies suggest that people who sleep less are more likely to have a higher body mass index (BMI) and develop obesity, says Trideep Kumar Choudhury, consultant psychiatrist at Fortis Flt. Lt. Rajan Dhall Hospital in Delhi. Sleep affects the levels of two hormones, leptin and ghrelin, which control feelings of hunger and fullness. Leptin tells the brain we have had enough to eat.

“Without enough sleep, the brain reduces leptin and increases ghrelin, which increases our hunger. This explains why someone likes to overeat at nighttime, leading to unwanted weight gain,” explains Dr Choudhury. Proper and adequate sleep at night can also help people keep their blood sugar under control. “Sleep deprivation causes the body to release less insulin after we eat. This hormone helps to reduce the blood sugar level. Thus, lack of sleep can lead to diabetes mellitus,” adds Dr Choudhury. Disruption of sleep and circadian rhythms may increase vulnerability to digestive disorders, including reflux, ulcers, inflammatory bowel issues and irritable bowel disease.

Impact on mental health

Sleep is also critical to our ability to think clearly, be vigilant and alert and sustain attention; memories are consolidated during sleep and sleep serves a key role in emotion regulation, says Dr Choudhury. Insufficient sleep can lead to irritability, fatigue, difficulty with concentration and memory and problems with socialising, leading to feelings of loneliness. These effects can contribute to more severe mental health disorders, such as psychosis or mania, in the long term, warns Dr Kovale.

Indications of sleep deprivation could include excessive fatigue through the day, frequent yawning and irritable behaviour. Research has found that people who sleep less have a decreased ability to take in and process bits of new information and to focus attentively while performing a task, which impairs the ability to judge situations accurately and respond accordingly.

“Inadequate sleep can take a toll on our psychological well-being, affecting our emotional and psychosocial interpretation of events and increasing our stress level, which, in turn, increases our risk of cardiovascular diseases. Studies have shown that inadequate sleep also increases our tendency to select and remember the negative memories, thereby affecting the processing of our emotional memory, and thus affecting our mood and feelings,” says Dr Choudhury.

Shrenik Avlani is a writer and editor and the co-author of The Shivfit Way, a book on functional fitness.

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