Night owls at greater risk of heart disease than people who rise early, study shows

Researchers say differences in fat metabolism need to be investigated further

Earlier risers were found to be better at burning fat (AFP via Getty Images)

Night owls could be more likely to develop heart disease and type 2 diabetes than people who rise early because of metabolic differences determined by sleep patterns, a new study has found.

Researchers from Rutgers University in the US discovered that those who stay up later have a reduced ability to use fat for energy.

As a result, fat is more likely to build up in their bodies, increasing the risk of cardiovascular disease and diabetes.

People who wake up earlier burn more fat at both rest and during exercise, according to the research, which tested two groups with different circadian rhythms.

All participants ate a nutrition-controlled diet and fasted overnight. They also completed two 15-minute spells of exercise each day.

The bodies of those in the “night owl” group were found to favour carbohydrates over fats as an energy source.

These people were also insulin resistant, meaning they needed more of it to lower blood glucose levels, something which gives them a higher likelihood of suffering from heart disease or type 2 diabetes.

The study’s authors said it was not known why the groups have different metabolic preferences, adding that the subject needs further investigation.

Senior author, Professor Steven Malin, whose study was published in Experimental Physiology, said: “The differences in fat metabolism between ‘early birds’ and ‘night owls’ shows that our body’s circadian rhythm (wake/sleep cycle) could affect how our bodies use insulin.

“A sensitive or impaired ability to respond to the insulin hormone has major implications for our health.”

He added that his research suggested that early birds have higher fitness levels than night owls, who tend to be more sedentary during the day.