Night owls may be more prone to heart disease and diabetes than early risers because their bodies are less able to burn fat for energy, US researchers say.
People who get up early rely more on fat as an energy source and are often more active during the day than those who stay up later, meaning fat can build up more easily in night owls, the scientists found.
The findings may help explain why night owls are at greater risk for type 2 diabetes and cardiovascular disease, and may help doctors identify early-stage patients who are more likely to develop the conditions.
“This could help medical professionals consider another behavioral factor that contributes to disease risk,” said Prof. Steven Malin, senior author of the study and expert in metabolism at Rutgers University in New Jersey.
The researchers divided 51 obese middle-aged adults into early risers and night owls, based on their answers to a questionnaire about sleep and activity habits. They monitored the volunteers’ activity patterns for a week and tested their bodies’ fuel preferences at rest and while performing moderate or high-intensity exercise on a treadmill.
In Experimental Physiology, the team describes how early birds were more sensitive to blood levels of the hormone insulin and burned more fat than night owls at rest and during exercise. The night owls were less sensitive to insulin and their bodies preferred carbohydrates over fat as an energy source.
Malin said it was unclear why differences in metabolism were seen in night owls and early risers, but one possibility, he thinks, is a mismatch between the time people go to bed and wake up the next morning and the circadian rhythms that control their body clocks. determine.
“Night owls reportedly have a higher risk of obesity, type 2 diabetes and cardiovascular disease compared to early risers,” he said. “One possible explanation is that they are misaligned with their circadian rhythm for various reasons, but especially in adults would be work.”
If someone is a night owl, Malin added, they may prefer to go to bed late but still have to get up early to go to work or take care of the kids, and this can force them not to be on their biological to stand the clock. while they prefer to sleep.
The findings could influence discussions about the health risks of night shifts and even changing the clocks to adjust daylight. “If we promote a timing pattern that is out of sync with nature, it could exacerbate health risks,” Malin said. “Whether dietary patterns or activity can help reduce these is one area we hope will become clear in time.”