While studies have previously demonstrated that shift-work and various other disruptions of the body’s internal clock may increase the likelihood of obesity and diabetes, researchers have not been able to paint a clear picture of how these changes and alterations to the internal clock affect our metabolism directly.
Not until, Dr. Orfeu Buxton of Harvard Medical School and his team of researchers began a study to investigate these correlations.
Buxton and company gathered 21 volunteers to participate in a controlled laboratory scenario, where their sleep-wake cycles would be constantly disrupted. For a little over a month, the research team observed the sleeping, eating, and exercising habits of the study’s participants. While this experiment is not the first to explore and observe the effects of disrupting the body’s natural circadian rhythm, it is the most extensive and longest running to date.
The most specific motivation for this project was to study the effects of long-term changes to an individual’s circadian rhythm on metabolism and more importantly, risk of diabetes.
Initially, participants would spend 10 hours in bed each night for a period of more than adequate sleep. The research team then began to gradually detract from this initial 10-hour period. Additionally, the volunteers were woken up four hours later on a daily basis to emulate the sleep disruption of travelling from east coast to west coast time zones as well as emulating the effects of irregular shift work.
Buxton and his team observed that at the end of the experiment, the average resting metabolic rate of his volunteers had fallen 8% from the starting rates. Such a massive drop of metabolism can easily translate into massive weight gains, even if diet and exercise remains consistent. This link between erratic sleep and slowed metabolism may offer an explanation as to why night shift workers have a higher likelihood of obesity, heart disease, and diabetes.
On top of all of these findings, Buxton’s team also discovered another reason why irregular sleepers are at higher risk of diabetes. Not only did the volunteers see a drop in their metabolism, their insulin levels were also affected. About half way into the experiment, the volunteers’ pancreases were producing over a third less insulin in response to their meals. With rising blood-glucose levels in response to less insulin, three volunteers quickly qualified as Pre-Diabetic.
The majority of previous studies have explored the effects of sleeping less, but these studies did not do so while also examining alterations to the body’s natural rhythm. More than ever, the importance of sleep-wake cycle management to the prevention of diabetes. Is transparent.