A study published in the Annals of Internal Medicine in 2010 found that participants who were sleep-deprived burned fewer calories than those who were well-rested. The study participants were divided into two groups, one of which was allowed to sleep for 8.5 hours each night, while the other group was limited to 5.5 hours of sleep. After two weeks, the researchers found that the sleep-deprived group burned an average of 111 fewer calories per day than the well-rested group.
The Impact of Sleep on Appetite
In addition to its impact on metabolism, sleep can also affect appetite. Sleep deprivation has been linked to an increase in the production of the hormone ghrelin, which stimulates hunger. At the same time, it can decrease the production of the hormone leptin, which signals fullness.
A study published in the Journal of Clinical Endocrinology and Metabolism in 2004 found that participants who were sleep-deprived had higher levels of ghrelin and lower levels of leptin than those who were well-rested. This led to an increase in appetite and a preference for high-calorie, high-fat foods. The researchers concluded that sleep deprivation could be a risk factor for obesity and other metabolic disorders.
The Impact of Sleep on Physical Activity
Another way in which sleep can impact weight loss is through its effect on physical activity. Sleep deprivation can lead to fatigue and decreased motivation, which can make it difficult to engage in regular exercise.
A study published in the Journal of Sleep Research in 2015 found that participants who were sleep-deprived had lower levels of physical activity than those who were well-rested. The study participants wore accelerometers to measure their physical activity levels for a week. The researchers found that those who slept less than six hours per night had lower levels of moderate-to-vigorous physical activity than those who slept for more than seven hours per night.
The Relationship Between Weight Loss and Sleep Quality
While it is clear that sleep can have a significant impact on weight loss, the relationship between weight loss and sleep quality is more complex. While some studies have found that poor sleep quality is associated with an increased risk of obesity and metabolic disorders, other studies have found no significant relationship between sleep quality and weight loss.
A study published in the International Journal of Obesity in 2012 found that participants who slept poorly had a higher risk of developing obesity and metabolic disorders than those who slept well. However, a meta-analysis published in the same journal in 2015 found no significant relationship between sleep quality and weight loss. The researchers concluded that more research was needed to fully understand the relationship between sleep quality and weight loss.
The link between weight loss and sleep is a complex one. Research has shown that sleep deprivation can impact metabolism, appetite, and physical activity levels, all of which can make it more difficult to lose weight.