Negative Effects of a Sedentary Lifestyle on Sleep Quality

Stages of Sleep 

Studies have found that sleep is important for the regeneration and repair function of the body. Sleep helps in regulating one’s mood, normalising heart pressure, increasing insulin sensitivity, and increasing immunity and brain functions. The main stages of sleep and their effect on metabolism are as follows:

1. Deep Sleep or Non-Rapid Eye Movement Sleep (NREM)  

In NREM sleep, the blood pressure lowers down, body temperature decreases, breathing slows, and the metabolic rate of the body reduces. The body secretes growth hormones (GH) at stage II of NREM sleep. GH lowers blood glucose levels and promotes cell growth.

2. Rapid Eye Movement Sleep (REM)

This is the most metabolically active stage of the sleep cycle. Testosterone and cortisol hormones are released. The brain increases its activity to tone up the muscle, which increases eye movement and leads to dreaming. Our body becomes more insulin sensitive because dreaming requires energy consumption. Therefore, uninterrupted sleep has been linked with increased longevity and decreased obesity.

Effects of Sleep on Basal Metabolic Rate

We burn up to 50 calories per hour during our sleep. This depends on the basal metabolic rate (BMR). BMR is the amount of energy required for performing all the important body functions such as heartbeat, circulation, breathing, temperature control and cell growth and repair. BMR consists of about 80 percent of our total energy requirement, with the brain alone taking 20 percent of daily energy needs.

Sleep is essential for maintaining our circadian rhythm and the daily sleep-wake cycle that acts as our biological clock. It works synchronised to earth’s daily rotation of light and dark and our lifestyle. Circadian rhythm affects various functions of our body such as immune responses, hormonal secretions and levels of neurotransmitters and performs in tune with every cell in the body and brain.

Different hormones play a crucial part in retaining circadian rhythm. Melatonin is a sleep-inducing hormone whose level increases when it is dark. Cortisol is a stress hormone that makes us more alert, whose level decreases at night-time. Another important hormone is leptin, the satiety hormone that prevents hunger when our body does not have sufficient stored fat. At night leptin levels are increased to avoid interruption in sound sleep due to hunger pangs. All this helps in maintaining good metabolic health and unwanted weight gain.

Effects of a Sedentary Lifestyle on Sleep

A sedentary lifestyle is one of the most common risk factors for obesity and diabetes, which increases with insomnia and sleep deprivation. Working late nights, shifting duty hours, jet lags, medications and stress are the key causes of an imbalanced circadian rhythm.

• Late sleepers often experience less amount of NREM sleep, which can lead to high blood pressure and glucose, increased heartbeats and metabolic syndromes. An efficient quantity of NREM sleep is essential for insulin activity and blood glucose regulation.
• Lack of sleep increases the level of a hunger hormone called ghrelin and decreases leptin levels as observed in people with obstructive sleep apnea (OSA) which causes intermittent sleep due to lapse of breathing at times. Ghrelin secreted from the stomach stimulates hunger and one ends up snacking on junk foods at midnight. Also, in individuals with OSA increased CRP levels bind with circulating leptin increasing leptin resistivity which again favours ghrelin activity disrupting weight management.
• Increased levels of the stress hormone cortisol during sleepless nights, keep the brain under high alert and induce a sudden surge in blood glucose levels. Repeated sleepless nights make them resistant to glucose sensitivity leading to insulin resistance and type 2 diabetes. Thus, sleep deprivation is directly related to physical inactivity and sedentary attitude.
• Interrupted sleep cycles are similarly detrimental. Studies show that fragmentary sleep deprivation on subjects, for merely 6 nights, can create type 2 diabetes-like syndromes, even in healthy men.

Building Good Sleep Habits 

Good sleep habits are often identified by scientists as sleep hygiene that helps one to get quality sleep. Some of these are noted below :

• Maintaining a consistent routine. Going to sleep and waking up at the same time every day helps in restoring one’s circadian rhythm.
• Environment of the sleep chambers helps to promote good sleep. The bedroom should be calm, dark, and cool temperature with a relaxed surrounding as light prevents melatonin synthesis.
• Electronic devices such as cell phone, TV, laptop or anything with a blue screen are harmful to sleep as it prevents the secretion of melatonin, the sleep-inducing hormone.
• Food Habit. Overeating just before sleeping prevents the sleep hormones secretion as the body becomes more metabolically active. Also, coffee or any caffeinated products, high sugar foods, and drinking alcohol spike the metabolic rate in the body keeping us awake.
• Avoid taking unnecessary day naps, as it can reduce nighttime sleep which is essential for body repair.
• Regular exposure to sunlight helps fix a disbalanced circadian rhythm.
• Regular exercise. It keeps our body active during the daytime, burning extra calories and exhausting us, making our sleep more deep and relaxed.
• Smoking before sleep is also bad, as nicotine can cause sleep disorders.

Bottomline

It can be concluded that for healthy adults it is essential to have a good seven to nine hours of sleep at night which is even greater for children. Sleeping and a sedentary lifestyle through both low activity processes have different outcomes. Sedentary behaviour leads to obesity whereas; a proper sleep pattern acts as protection against it as well as promotes better metabolic health. Sleep is important for improving mental health, regular body recovery, longer life and all-around wellness.