Adults who slept about 80 minutes less each night gained an average of one pound over six weeks and spent more time inactive, according to a Columbia University study examining the effects of mild sleep restriction.
By yourNEWS Media Newsroom
Regularly losing even a modest amount of sleep may contribute to weight gain and reduced physical activity, according to research from Columbia University Irving Medical Center.
The study followed 95 adults who normally slept between seven and eight hours per night and examined what happened when they reduced their nightly sleep by approximately 80 minutes for six consecutive weeks.
By the end of the shortened-sleep period, participants had gained an average of one pound and were spending more of their day sitting or otherwise inactive, the researchers reported.
The findings suggest that the type of sleep loss commonly experienced by people who delay bedtime by an hour or two may produce measurable changes in body weight and behavior even without severe or total sleep deprivation.
Approximately one-third of American adults regularly sleep fewer than seven hours per night, according to data from the Centers for Disease Control and Prevention. Many are not staying awake through the night but are instead repeatedly cutting relatively small amounts of time from their normal sleep schedules.
The Columbia study was designed to examine the consequences of that more common pattern.
During one portion of the trial, participants followed their normal sleep routines. During another phase, they postponed bedtime by 90 minutes, which reduced their actual sleep duration by about 80 minutes per night.
The shortened schedule continued for six weeks.
Researchers used wearable activity monitors, accelerometers and laboratory testing to track changes in body weight, body composition, waist circumference, appetite-related hormones and daily movement.
After six weeks, participants had gained an average of one pound.
They also spent about 17 additional minutes per day sitting or inactive. Among male participants and postmenopausal women, the increase in sedentary time approached 30 minutes per day.
The reduction in activity occurred even though participants were awake for a longer period, suggesting they did not use the extra waking time to move more.
Instead, researchers observed what appeared to be a voluntary or behavioral decline in movement.
“The changes we observed were modest but consistent,” said Marie-Pierre St-Onge, PhD, the study’s senior author and a professor of nutritional medicine at Columbia University Irving Medical Center. “While that amount of weight gain may seem small, it’s important to note that it happened over a relatively short period.”
The study adds to previous research from the same team showing that partial sleep loss may affect several aspects of metabolic health.
Earlier findings from the researchers indicated that modest sleep restriction increased insulin resistance among women at elevated cardiometabolic risk and produced inflammatory changes associated with heart disease.
The latest results suggest that mild sleep loss may also influence weight and physical activity, even when the reduction resembles ordinary late bedtimes rather than extreme sleep deprivation.
Researchers noted that gaining one pound over six weeks may appear minor when considered in isolation. Repeated over months or years, however, small changes in weight and movement could accumulate and contribute to larger metabolic consequences.
Several biological and behavioral mechanisms may help explain the association.
Previous studies have found that inadequate sleep can alter hormones involved in hunger and fullness, including ghrelin and leptin.
Ghrelin typically rises when the body experiences negative energy balance and can increase hunger and encourage food intake, according to the textbook “Understanding Nutrition.”
Sleep loss may also reduce insulin sensitivity and affect food preferences, potentially increasing interest in calorie-dense or highly processed foods.
The “Handbook of Nutrition, Diet and Sleep” describes reciprocal connections between sleep-wake patterns and the body’s regulation of fuel availability. Those interactions are partly mediated by orexin, also known as hypocretin, signaling pathways in the brain.
Those systems influence wakefulness, appetite, energy expenditure and metabolic regulation.
The handbook also notes that although the increase in obesity risk associated with short sleep may be modest for an individual, the public health effect can become substantial when applied across a large population.
The Columbia study did not directly test each of those mechanisms, but the researchers said its findings are consistent with the possibility that repeated sleep restriction gradually alters metabolism, appetite and movement.
The results are particularly relevant because approximately 60 million Americans are estimated to experience sleep disorders or insufficient sleep.
Even small changes in weight or daily activity could have broad consequences when occurring across such a large segment of the population.
The findings do not establish that every person who sleeps less will gain weight, and weight regulation remains influenced by diet, physical activity, genetics, hormones, medications and other health conditions.
The study does, however, provide evidence that ordinary patterns of sleep reduction may contribute to metabolic changes over a relatively short period.
Researchers recommended treating sleep as part of an overall health routine rather than as time that can be repeatedly sacrificed without consequences.
Maintaining a consistent bedtime, reducing screen exposure before sleep and allowing enough time for at least seven hours of rest may help support weight regulation and metabolic health.
“Protecting sleep may be one of the simplest ways to support metabolic health,” the report stated.
Source: Natural News
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