Giving up a little sleep to squeeze in another episode might seem harmless, but new findings suggest it can have real consequences for your waistline, your energy and your long-term health.
According to a new study published in Annals of Internal Medicine, cutting about 80 minutes of sleep each night may slowly lead to weight gain and a more sedentary lifestyle.
The research followed 95 adults who normally got between seven and eight hours of sleep per night. During the trial, participants were asked to push their bedtime back by 90 minutes, reducing their sleep by an average of 78.4 minutes.
After only six weeks on the shorter sleep schedule, the group had gained about one pound on average.
That may not sound dramatic, but sleep experts say the effect can add up when the loss continues night after night. Even losing just one hour of sleep a night can create a sleep debt that affects how you feel and function the next day, including your focus, reaction time and appetite.
In addition to the weight changes, the study found that participants were less active when they slept less.
While on the restricted sleep plan, they spent an average of 17 more minutes being sedentary during the day.
Among men and postmenopausal women, that increase in inactivity rose to nearly 30 minutes per day.
Study author Marie-Pierre St-Onge, from Columbia University, explained exactly what this means for the general public: “The main takeaway is that sustaining a reduction in sleep, to a duration that is often observed in the general population, leads to weight gain and increases in waist circumference.”
St-Onge explained: “Weight gain occurs through an imbalance in energy expenditure and energy intake favoring greater intake relative to expenditure (or conversely low expenditure relative to intake).”
The research did not stop at weight gain. Investigators also found that people became less active when they were sleeping less.
Reduced sleep can also interfere with the body’s metabolic and cardiovascular systems. Public health guidance from the CDC and NIH notes that adults generally need at least seven hours of sleep a night, and that regularly getting less sleep is linked with higher risks of obesity, high blood pressure, diabetes and heart disease.
Earlier assessments from the Columbia team have also found increased insulin resistance in women already considered at elevated risk, a change that can raise the likelihood of developing type 2 diabetes.
The same line of research has identified signs of cellular inflammation affecting the heart in people exposed to prolonged mild sleep restriction. Combined with higher stress hormones and inflammation, that may contribute to a greater long-term risk of cardiovascular disease.
Previous studies have also shown that major sleep deprivation can increase appetite by raising ghrelin, the hormone linked to hunger, while lowering leptin, which helps signal fullness.
Even a single short night can have noticeable effects the next day. People may feel groggy, less patient and less motivated to move around, which may help explain why repeated sleep loss can slowly shift habits toward more sitting and less activity.
To improve sleep hygiene, St-Onge recommends gradually extending time in bed so the body can adjust more naturally. She also advises cutting out behaviors that make it harder to fall asleep, including eating too close to bedtime and consuming caffeine late in the day.
Making sleep a priority, along with maintaining a balanced diet and regular exercise, is an important step in reducing the risk of obesity and other long-term health issues.