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When we sleep matters more than we realize. Photo: iStockphoto
When we sleep matters more than we realize. Photo: iStockphoto

Sleep on time for healthy immunity

Uninterrupted sleep is needed to consolidate memory, repair muscles and release the hormones that regulate growth and appetite

Most of us know we are supposed to get enough sleep, but not many are aware that when or what time we sleep also matters. Sleeping late can have specific, negative consequences.

“That’s because from 11pm-3am, we have more of NREM (non-rapid eye movement) sleep and this is essential for the restoration and healing of our organs. From 3-7am, we are more likely to get REM (rapid eye movement) sleep, characterized by vivid dreams. So those who sleep late habitually miss out on the restorative sleep hours (which fall between 11pm to 3am)," says Manisha Arora, senior consultant, internal medicine, Sri Balaji Action Medical Institute, New Delhi.

Today, unfortunately, a lot of us are struggling with sleep. “Six out of every 10 people I see in my OPD today suffer from sleep problems, leading to complaints of daytime exhaustion," says Sundari Srikant, senior consultant, internal medicine, QRG Health City, Faridabad, near Delhi.

You need uninterrupted sleep to consolidate memory, repair muscles and release the hormones that regulate growth and appetite. “It also regulates moods, reduces anxiety, and enhances focus, concentration, social skills and healthy decision making. Lack of sleep can affect our metabolism and weaken the immune system and that’s when one becomes susceptible to multiple health problems," says Dr Srikant. So pay attention to your sleep patterns.

Who is at risk?

Those in the 20-35 age group are at maximum risk of not getting enough sleep, says Rahul Modi, sleep medicine specialist and ENT at the Dr LH Hiranandani Hospital, Mumbai. “Additionally, those who work in shifts—workers who do evening/night shifts—are also often not able to meet their sleep quota. Often, although they sleep late, they have to wake up early to drop their children to school or complete household chores," he adds.

Very often, says Sonal Anand, consultant psychiatrist at the Wockhardt Hospital in Mumbai, the reasons for sleeping late are work or screen addiction. “I am also very surprised with the trend of young, school-going children waiting up for their parents to arrive from work and as a result going to sleep very late at night," she says.

In fact, says Dr Anand, people of all ages and professions are scrimping on sleep, sleeping late, and then trying to make up for this by taking an afternoon nap or early evening nap, or binge-sleeping on weekends. That doesn’t help.

Health implications

Sleeping late compromises immunity. The body’s internal clock is set for two 12-hour periods of light and darkness, and any disruption of this rhythm affects the immune system too, as the genes that set the body clock are intimately connected to certain immune cells.

“There may be some sugar trouble too as chronic lack of sleep may even contribute to the risk of type 2 diabetes mellitus by bringing measurable changes in glucose metabolism, hormone levels and autonomic nervous system activity," warns Dr Arora.

Dark circles under the eyes are a common tell-tale sign of wrong sleeping patterns. A study published in The Journal Of Clinical Endocrinology & Metabolism in 2010 found that sleep loss caused by sleeping late can lead to the body releasing too little human growth hormone; this, besides taking a toll on energy levels and contributing to fatigue, can also accelerate ageing of the skin.

Weight woes

Poor sleep is connected to an increase in appetite and weight gain. “This is partly due to the connection between sleep and the peptides that regulate our appetite: ghrelin and leptin. Ghrelin, which makes us hungry, goes up when we don’t get enough sleep. And leptin, which sends ‘full’ signals to the brain, decreases due to sleep deficit," Dr Srikant explains.

According to the results of a study published in ScienceDaily in June last year by the Feinberg School of Medicine at Northwestern University, US, sleeping late could be one of the unhealthiest ways to kick off your morning. So dark circles under the eyes are the least of your problems.

Mind troubles

Sleeping late is even associated with lower perceived control over obsessive thoughts, according to new research from Binghamton University, State University of New York, published in April in the journal Sleep. Dr Anand explains: Our bodies have evolved in a way that circadian rhythms are set and the body realizes that it is time to rest after sundown due to the secretion of “melatonin", a hormone known to regulate the sleep-awake cycle.

Staying awake late, then, is like a self-inflicted injury.

So keep a check on jet lag, shift work, and unnecessary late nights staring at your tablet or smartphone—it could all be making you sick. “Keep your own sleeping patterns more aligned with nature, limit exposure to artificial light at night, draw the curtains, keep the phone off, and sleep on time," advises Dr Arora.

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