Sleep and Weight Loss
Sleep and Weight Loss

Does how many hours a person sleeps each night have an effect on weight? According to recent research the answer is yes. Dr Muhamad Usman gives the why and how.

Sleep and Weight Loss

By wlr Contributor Dr Muhamad Usman MD

Does sleeping help you lose weight? The answer is yes - if you're not getting enough sleep, sleeping restfully for 7-8 hours each day can help you lose weight. The evidence has built up in recent years and goes some way towards explaining how getting a healthy amount of sleep, or not, can affect your weight.

What Does the Research Say?

Numerous studies in recent years have explored the relationship between sleep duration and weight loss.

For instance, researchers at Cleveland systematically reviewed 36 studies and found that shorter sleep duration is strongly associated with obesity.1 Another study found that in addition to decreased quantity of sleep, decreased quality of sleep2 can also lead to obesity.

Researchers at the University of Warwick, UK went a step further and found the exact weight gain that sleep deprivation can cause. In an analysis of 45 studies, they found that a reduction of one hour sleep each night translates into a weight gain of 1.4 kg3 in an average individual.

In their study of sleep and weight, Korean researchers confirmed the relationship of reduced sleep with weight gain and suggested increasing sleep duration4 for weight control in overweight individuals.

How Does Lack of Sleep Lead to Weight Gain?

You’re probably puzzled by all these findings. After all, how can hours spent lying in bed possibly reduce your weight? Reducing these hours of inactivity should decrease your weight, not increase it, right?

While scientists still haven’t been able to fully solve this puzzle, they have advanced various theories to explain it. The most probable of these include:

More Impulsivity

Depriving your brain of sleep results in decreased activity of the frontal lobe of the brain- the part of the brain involved in controlling impulses. So, reduced sleep means more impulsivity.

Where you would normally stop after eating a single slice of cake or a single chocolate, sleep-deprivation would make you eat the whole cake or several chocolates.

So, inability to resist food craving in a sleep-deprived brain can be a cause of weight gain.

More Snacks and Drinks

Researchers have found that sleep-deprived individuals tend to pass their time at night by consuming more snacks and beverages.5

These snacks and drinks are often high in sugar and/or refined carbohydrates, and are notorious for causing weight gain. Such night-time eating habits, combined with increased impulsivity, are a probable cause of weight gain in individuals who don’t get enough sleep.6

Excess Calories

The two points above could explain why researchers at Kings College London found that people classed as sleep deprived (3½ to 5½ hours a night) ate an extra 385 calories a day.

Metabolism and Energy Expenditure

Japanese researchers claim that dietary patterns only explain a part of this puzzle. According to them, other physiological causes7 such as altered glucose metabolism and reduced energy expenditure in sleep-deprived individuals play a greater role in increasing their weight.

It means that the metabolism of sleep-deprived individuals becomes sluggish and starts turning more energy into fat, eventually leading to weight gain.

Hormones and Inflammatory Pathways

Some researchers have found that reduced sleep can alter several hormones in your body increasing your appetite,8 making you eat more and finally leading to weight gain.

Still others think that sleeping less can activate inflammatory pathways9 in the body, which can then result in obesity and weight gain.

Finding the Balance

So, while the act of sleeping itself doesn’t reduce weight, lack of sleep can increase your weight through mechanisms mentioned above.

If you often get inadequate sleep, improving your sleep quality and increasing your sleep duration will definitely help you to lose weight.

This doesn’t mean, of course, that you should start sleeping more than necessary and spending all your time in bed to reduce your weight.

In fact, increased sleep duration and napping have been associated with increased mortality rates in a number of scientific studies. For instance, a recent study found that both increase and decrease in sleep hours from an average of 7-8 hours a day are associated with greater mortality10.

Similarly, researchers at the University of Cambridge, UK found that daytime napping, more than one hour a day, was associated with increased mortality in British population11. While researchers don’t know the exact cause, increased sleep appears to increase death rate from cardiovascular disease and cancer.

What Does This Mean for You?

It's pretty clear that 7-8 hours sleep each night is the perfect balance. Sleeping less than this will make it more difficult to lose weight, while sleeping more than this is not thought to be generally healthy.

So, if your normal night's sleep averages less than 7 hours, it will be worthwhile taking steps to improve your sleep quantity and quality - and not letting anything get in the way of a good night’s sleep of 7-8 hours.

If on some nights you can’t go to sleep on time, try to avoid consuming extra snacks and calorific drinks, since this is considered a major cause of increased weight in the sleep-deprived.

Tips for a Better Night’s Sleep

  1. Go to bed and get up at a fixed time each day. Altering your routine often can disturb your sleep.
  2. Make sure that your bedroom is dark and noise-free when you go to bed. Both noise and light can adversely affect the quality of your sleep.
  3. Use your bed only for sleeping. This way your mind will automatically start relaxing every time you go to bed. You should avoid watching TV, reading books or listening to music in your bed.
  4. Avoid coffee, tea or other stimulants in the evenings. Such stimulants can disturb your natural sleep-wake rhythm.
  5. Get some exercise in the afternoon or evening. Relaxing exercise close to bedtime can improve the quality of your sleep.

A Good Night’s Sleep

There is nothing quite as healthful as a good night’s sleep. It washes off your physical exhaustion, refreshes your mind to take on the challenges of the next day and as you’ve learned from the scientific evidence presented here, it can also help with weight control.

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