[Reporter Jang Jong-ho, Sportschosun] A study has found that sleeping just about 80 minutes less than usual each night can lead to an average weight gain of about 0.45 kg in six weeks.
The study also found that spending more time sitting instead of sleeping may raise the risk of obesity and cardiovascular disease (CVD).
A joint research team from Columbia University and another university in the United States conducted a 12-week clinical trial involving 95 adults who normally slept about seven to eight hours a day. During the first six weeks, participants delayed their bedtime by 90 minutes to reduce sleep time, and for the following six weeks they returned to their original sleep pattern.
During the study period, participants wore wrist-worn activity trackers to record their sleep time, while the researchers continuously measured changes in body weight, waist circumference, body composition and fasting appetite-related hormones.
The analysis showed that actual average sleep time fell by about 80 minutes a day, and the participants gained an average of about 0.45 kg over six weeks.
The researchers said the same trend, if it continued for a year, could lead to a clinically meaningful amount of weight gain.
Previous studies had shown that extreme sleep deprivation, such as sleeping only about four hours a day, can increase appetite and lead to overeating. However, the researchers carried out this study to see whether the more common sleep loss of around one hour also affects health.
"The weight gain seen over six weeks may not seem large, but it is the result of a very short period," the researchers said. "If sleep loss of less than 1 hour and 30 minutes a day continues for more than a year, it could lead to a meaningful increase in weight that affects health."
The study also found changes in physical activity. During the period of insufficient sleep, participants spent an average of 17 more minutes sitting each day, and sedentary time increased by about 30 minutes a day among men and postmenopausal women in particular.
As sleep time decreased, overall activity levels also fell, rather than simply leaving more time awake. The researchers warned that "a sedentary lifestyle increases the risk of various chronic diseases."
The researchers added, "The exact mechanism by which sleep deprivation causes weight gain requires further study, but existing findings all suggest that not getting enough sleep may increase the risk of obesity, Type 2 diabetes (T2D) and cardiovascular disease (CVD). Future research is needed to determine how much health improves when people get enough sleep."
The findings were recently published in the international journal Annals of Internal Medicine.
Reporter Jang Jong-ho, bellho@sportschosun.com
