Discover why sleep is so important for managing your weight
It’s nearing the end of the long summer holiday. Soon, our daily schedules will be upon us. For many of us living in fast-paced Hong Kong, this can mean long days and nights, which most likely affect our sleep patterns.
But would you prioritise more sleep if you knew that burning the midnight oil (or, indeed, scrolling through your phone mindlessly at midnight) could make you put on excess weight, alongside many other negative health effects?
The importance of sleep
Sleep plays a vital role in regulating metabolism and appetite. When we lack even a small amount of sleep, the metabolic system goes out of balance, affecting our dietary choices and the way we metabolise calories.
It’s no coincidence that while our average sleep time decreased between the 1950s to 2000s—from about 8.5 hours to 6.5 hours per night—there has been an increase in the prevalence of obesity from about 10 per cent to about 23 per cent. Overworking, device addiction, increased travel, etc. have all played a role in reducing sleep-time.
Cortisol and insulin
To understand further, let’s look at two key hormones: cortisol and insulin. Cortisol is known as the “stress hormone,” and sleep deprivation triggers a spike in its production. Cortisol then signals your body to conserve energy to fuel your waking hours, a defence mechanism designed to protect the body from perceived stressful conditions. The bottom line is, you’re more likely to hang on to fat with increased cortisol levels.
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Summing this up, University of Chicago researchers report that sleep deprivation makes us “metabolically groggy.” Within just four days of insufficient shut-eye, your body’s ability to process insulin—a hormone needed to change sugar, starches, and other food into energy—goes out of balance, meaning we are less likely to burn off excess calories from these sources.
Further research shows that REM (rapid eye movement) sleep is when we also burn fat, so the more you sleep, the more REM sleep you'll get to burn more calories.