Can lack of sleep cause weight gain?

A lot of us have pulled an all-nighter or two in our lives. Sometimes it’s because of work or school; other times, it’s because you can’t stop binge-watching that new series on Netflix. A one-off sleepless night might feel harmless, but sleep deprivation can have real consequences on your well-being.

We’ve known for a long time that a good night’s sleep is essential to good health. It improves your mood and your brain performance, and removes toxins from your body. Your entire self uses your time asleep as a time to “heal” and repair everything from blood vessels to your immune system. [1]

So what happens if you don’t snooze for long enough? And what does that have to do with weight – especially gaining it?

Causes and effects of lack of sleep

Many things can cause people to become short on sleep. Sometimes these are external factors, such as a large work project or school assignment. Other times, the causes are more internal – stress, depression, insomnia, or even a condition termed “sleep apnea.” [2]

Whatever the cause, lack of sleep can have short- and long-term consequences on our health.

Short-term effects of sleep deprivation

Many of us know the feeling of irritability after a poor night’s sleep, but that’s just one of the short-term effects. Poor sleep can affect your judgment and lower your inhibitions, alongside affecting your ability to learn and retain information. Your brain hasn’t had adequate rest and time to prepare for a new day, so it’s performing more poorly than usual.

Severe sleep deprivation can also lead to a rise in the risk of accidents and injury. [3]

Long-term effects of sleep deprivation

In the long-term, sleep deprivation can have far worse consequences. If you get 6 hours or less of sleep a night, you’re increasing your risk of:

  • Cardiovascular diseases
  • Endocrine conditions
  • Weakened immune systems
  • Damaged nervous systems

This can cause conditions such as hypertension, anxiety and depression, diabetes (or impaired glucose tolerance), and substance abuse. It can also lead to weight gain – and possibly obesity. [4]

Losing weight can be challenging, as can be maintaining weight once you’ve lost some pounds. But if you’re lacking sleep on top of that, you’re making things much more difficult.

Science is still trying to comprehend the complicated relationship between sleep and weight, but research has emerged linking lack of sleep to weight gain. Shorter sleep durations result in metabolic changes. In children, for example, insufficient sleep negatively affects the hypothalamus, which regulates appetite. [5]

In adults, sleep deprivation has similar effects as when your endocannabinoid (eCB) system is activated. The eCB system plays a key role in regulating your appetite and energy levels. In one study observing sleep and the eCB system, results showed that sleep-deprived participants had higher, longer-lasting eCB levels in their blood versus those who got full sleep. [6]

Lack of sleep also affects our metabolism – the processes by which your body turns food into energy. This is due to two hormones that our body produces at night: ghrelin and leptin.

Ghrelin signals your body when to eat, and sleep debt has associations with the production of more ghrelin. Meanwhile, leptin signals your body when to stop eating, and sleep debt has associations with less leptin. Therefore when you’re sleep deprived, you’re more likely to have an increased appetite and less likely to stop before you’re full. [7]

Additionally, your metabolism slows down when you’re sleep-deprived since you have less energy. This also leads to decreased physical activity since you’re more tired during the day. [8]

On the flip side, good sleep means more energy – which means you’re more likely to be active and to exercise. You’ll also have lower levels of ghrelin and higher levels of leptin, as well as a faster metabolism. [9]

Improving sleep hygiene

So – how to get better sleep? One factor is understanding your circadian rhythm. This process governs the way your body works throughout the day, receiving key signals of when to wake up and when to wind down. This cycle varies throughout your life, but it’s fairly consistent at each stage.

But an inconsistent circadian rhythm – meaning you don’t listen to your body when it’s time to sleep or wake up – leads to poor sleep hygiene. You’ll have a harder time falling asleep or waking up, and that means you’re not getting sufficient rest.

To help your circadian rhythm, you’ll need to sleep in a darkened room. A night light might not be so harmful, but bright lights – even in connected rooms – can impede your body’s signals that it’s time to snooze.

Additionally, don’t eat right before bed. [10] Your body will digest slower since it’s minimizing the energy it uses, so you’ll metabolise food slower as well.

Then there’s exercise, which doesn’t just help you lose weight. It’ll also improve your sleep quality and help you fall asleep more quickly. In particular, exercising during the day increases the amount of “slow wave sleep” or deep sleep you get, which is more restful for your body. [11]

Good sleep means good health

Bad sleep means poor health, good sleep means good health. While the connections aren’t completely clear, observationally, we can associate poor sleep with weight gain. Whether it’s because you snack more for a boost of energy or because you metabolize your food slower – you’re more likely to put on a few pounds if you don’t sleep well.

Maintaining good sleep hygiene is essential to your personal well-being. You’re happier and more energized, and less stressed. This bodes well for your overall health and longevity – and besides, who doesn’t love waking up feeling well-rested after a comfortable sleep?

REFERENCES

[1] https://newsinhealth.nih.gov/2021/04/good-sleep-good-health
[2] https://www.hopkinsmedicine.org/health/wellness-and-prevention/health-risks-of-poor-sleep
[3] https://healthysleep.med.harvard.edu/healthy/matters/consequences
[4] https://www.ncbi.nlm.nih.gov/books/NBK19961/
[5] https://www.cdc.gov/sleep/about_sleep/chronic_disease.html
[6] https://www.nih.gov/news-events/nih-research-matters/molecular-ties-between-lack-sleep-weight-gain
[7] https://www.webmd.com/sleep-disorders/features/lack-of-sleep-weight-gain
[8] https://www.hsph.harvard.edu/obesity-prevention-source/obesity-causes/sleep-and-obesity/
[9] https://www.health.harvard.edu/blog/snooze-more-eat-less-sleep-deprivation-may-hamper-weight-control-202204042718
[10] https://www.sleepfoundation.org/physical-health/weight-loss-and-sleep
[11] https://www.hopkinsmedicine.org/health/wellness-and-prevention/exercising-for-better-sleep

Photograph: Tero Vesalainen/Shutterstock

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The information included in this article is for informational purposes only. The purpose of this webpage is to promote broad consumer understanding and knowledge of various health topics. It is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.