Why Late-Night Shifts Can Lead to Obesity and Diabetes
Sleep Doctors Explore Circadian Rhythm and Metabolism
Results of studies have indicated that those working the night time shift and others with lifestyles that result in late nights out or frequent jet lag can potentially damage their internal body clocks. Disturbances as such, said sleep doctors, can lead to diabetes and obesity, among other conditions. The potential dangers of not getting enough sleep are already clear, but how the changes in the internal body clock affect metabolism remains still a big question mark for researchers.
Dr. Orfeu Buxton is an assistant professor of sleep medicine at the Harvard Medical School. Along with his associates, this sleep doctor developed a study to find out how sleep disturbances directly affected the internal body clock and metabolism. He conducted the study with 21 people kept under controlled conditions. The sleep cycles of each of his participants were purposely interrupted.
For over a month, the research team controlled how much sleep the participants were allowed to have, when their sleep was disturbed, what they ate and even how much they exercised. This is the longest study to take into detailed account natural circadian rhythm of the human body, said some sleep doctors. Previous studies were limited because they collected data only over the course of a couple of weeks.
These Harvard sleep doctors were interested in analyzing the specific effect that lack of sleep had on human metabolism and the development of diabetes. The sleep doctors focused on long-term or chronic modifications to the body’s internal clock or circadian rhythm. The variable was found most affected in late-shift workers and people who travelled often at night.
The Sleep Doctors’ Results
In the study, the subjects were first allowed to get an ample amount of sleep, at least 10 hours every night. Later, the sleep doctors gradually cut down this amount, so that subjects were subjected to fewer and fewer hours of sleep per night. Aside from not being able to sleep for a certain amount of hours, the patients were asked to sleep once and then wake up during the same night, after 4 hours of sleep, in order to replicate travelling across one time zone (from East to West) every day. Furthermore, the same subjects were asked to sleep during the day and then stay awake at night to replicate late-night shifts.
According to Dr. Buxton, the team created a schedule of disrupted sleep-wake cycles with various causes, included activities and diet, designed to mess with the natural alignment of the 24-hour body clock. Dr. Buxton admitted that the schedule was extreme and that usually people who suffered from lack of sleep didn’t have it so bad.
Regardless, what the sleep doctors discovered was that the subjects’ resting metabolic rate by the end of the fifth week dropped a total of 8 percent when compared with that of the first week with plentiful sleep. Extrapolated over one year, this inhibition could translate into an additional 10 pounds if the exercise and diet remained constant. These results offered an explanation as to why shift workers seemed to gain weight when they started to sleep irregularly. A tendency toward obesity, diabetes and heart problems is also common among this group.
The study also concluded that the reversal of the circadian clock (sleeping by day and staying awake at night) and general poor quality of sleep can also affect insulin levels. At the end of the third week, the participants produced nearly one-third less insulin than when they started the study. As soon as the participants went back to their regular sleep schedules, the insulin levels went back to normal.
The sleep doctors pointed out the fact that modified circadian rhythm along with inadequate sleep can affect the body more potently than if a person were just sleep deprived. Other studies which only made participants sleep less but did not subject them to out-of-place sleep disruptions garnered no significant difference in rate of insulin production.
The results of the Harvard sleep doctors highlighted how important the sleep-wake cycle can be for metabolism and health. Even healthy patients who are forced to work late or who choose certain lifestyles are putting their wellness at risk. The sleep doctors lead by Dr. Buxton are now looking into the possibility of studying pilot training prior to flying planes across time zones. The sleep doctors want to figure out whether real world situations as such would garner the same results as their subjects did under lab-controlled conditions.
Talk to sleep medicine doctors who diagnose sleep disorders if you have trouble sleeping or if you need help adjusting to a late night shift at work.
