Late Nights and Blood Sugar

Sunday, July 24, 2016

Going to bed and eating late linked with poorer glucose control

Keeping type 2 diabetes in check is a 24/7 challenge, says Rush’s Megan Hood, PhD. It may be even more challenging late in the day’s 24-hour cycle.

A psychologist and director of the Behavioral Health for Diabetes Program, Hood coaches adults who are having trouble managing their diabetes and related weight, stress, and mood issues. In many of her patients, she has noticed how much daily routines and rhythms — particularly when they eat or go to sleep — seem to affect their physical and mental health.

“Our minds and our bodies are so closely aligned,” says Hood, an assistant professor in Rush’s Department of Behavioral Sciences. “When the timing of our behaviors, like eating and sleep, are off from what our bodies seem to need, our mental and physical health seem to suffer.”

It already is well established that blood sugars become unbalanced if people do not eat enough or eat too much unhealthy food (such as sweets). A similar trend has been shown for shut eye: Sleeping poorly or getting too little or too much sleep can cause unhealthy increases in blood sugar.

Hood and her colleagues are taking this research a step further to see if out-of-control diabetes also may be tied to when people choose to sleep and eat.

A matter of timing

Humans evolved to eat during the day and sleep and fast at night. What are known as circadian rhythms, controlled by the brain’s central clock (an area called the suprachiasmatic nucleus) help people stick to this schedule. Circadian rhythms also influence various biological functions, including digestion and insulin production.

“How our bodies process the food we eat, particularly glucose, can differ depending on the time of day,” Hood explains. “Some initial studies have suggested that, when sleep habits don’t line up with natural circadian rhythms, it can affect beta-cell functioning.”

Beta cells are the cells in the pancreas that produce insulin, a hormone that the body needs to keep blood sugar balanced. “When beta cells aren’t functioning properly, people may have difficulty controlling their blood sugar,” Hood says.

Logging the hours

A lot of the research on this topic has been done in the laboratory, looking for cellular explanations for these biologic changes. Hood and her colleagues Stephanie J. Crowley, PhD, associate professor of behavioral sciences at Rush, and Sirimon Reutrakul, MD, an endocrinologist who now is at Mahidol University in Thailand, are taking a different tactic, focusing on the daily sleep and eating habits of people with diabetes and how those behaviors affect blood sugar.

In an initial study, they surveyed 194 adult patients with type 2 diabetes from Rush’s diabetes center. The patients provided information on their sleep and wake-up times, as well as what and when they ate, over a 24-hour period. The researchers also obtained a measure of blood sugar levels from patients’ medical records, usually measures taken the same day for which patients provided their sleep and eating information. 

“We found that a number of sleep and eating time variables, such as being a night owl rather than an early bird, skipping breakfast, and having more night-eating symptoms – for example, eating a large portion of your calories after the evening meal or getting up from sleeping to eat — are associated with poorer glycemic control,” Hood says.

The study yielded three publications in research journals, but Hood emphasizes that it’s just one step in determining a link between blood sugar and the timing of sleep and eating. “This was a single time-point study, but the effects are promising enough that we are planning to test an intervention, to see if changing when people with type 2 diabetes go to bed and when they eat can improve glycemic control.”

What patients can do

Hood cannot yet provide specific recommendations on when people with diabetes should go to sleep or eat to keep blood sugar in check. However, patients may want to set a consistent schedule, aiming to go to sleep at a reasonable hour, avoid late night snacking, and eat breakfast, she says.

But everyone needs to be fair to themselves when setting goals, Hood stresses. The preference to stay up late or rise with the birds varies. Every person’s circadian rhythms are set to a specific chronotype, or bedtime preference. At the same time, many people’s bedtimes are dictated by family, social, and work demands, particularly night shift work.

“Gathering data, which we call ‘self-monitoring’ in psychology, is key to learning more about your own behaviors and seeing patterns that may pop up,” Hood says. “There are so many new ways to gather this data, such as activity/sleep trackers and electronic food diaries.”

Patients should take this information and any questions they have to their next doctor appointment, Hood advises. “Your doctor can help you figure out strategies that are a good fit for you specifically.”

For media inquries, please contact kevin_mckeough@rush.edu.