Night owls are at greater risk of heart disease and type 2 diabetes than early birds, a new study has found.
A US study published in Experimental Physiology found that night owls – people who prefer to be active later in the day – have a reduced ability to use and burn fat for energy, allowing it to accumulate in the body.
This can lead to an increase risk of type 2 diabetes and heart diseasefound researchers from Rutgers University in New Jersey.
On the other hand, early birds – those who are more active in the morning – require more fat as an energy source due to being more energetic with more hours in the day and thus having a higher level of fitness than night owls owls
The researchers divided the participants into two groups based on their chronotype – our natural tendency to seek out activity and sleep at different times.
After a week of observation, the researchers found that the early birds consumed more fat for energy both at rest and during exercise than the night owls.
Each group was tested at rest before engaging in two 15-minute bouts of treadmill exercise, one at a moderate intensity and one at a high intensity.
After monitoring fuel preferences, individuals were tested for aerobic fitness on an incline, with the incline increasing by 2.5% every two minutes until the individual reached the point of exhaustion.
“Early birds are more physically active”
Participants were on a calorie-controlled diet and overnight fasting to reduce the chance that their diet would affect the results.
Senior author and Rutgers University professor Steven Mullin said: “Because chronotype appears to influence our metabolism and hormone action, we hypothesize that chronotype can be used as a predictor of human disease risk.
“We also found that early birds are more physically active and have higher fitness levels than night owls, who are more sedentary during the day.
“Further research is needed to examine the relationship between chronotype, exercise, and metabolic adaptation to determine whether exercise earlier in the day would confer greater health benefits.”