Metabolic differences between early birds and night owls could help predict diabetes, heart disease risk

Are you an early bird or a night owl? Our activity patterns and sleep cycles could influence our risk of diseases, such as type 2 diabetes and heart disease. New research published in Experimental Physiology found wake/sleep cycles cause metabolic differences and alter our body’s preference for energy sources. The researchers found that those who stay up later have a reduced ability to use fat for energy, meaning fats may build-up in the body and increase risk for type 2 diabetes and cardiovascular disease.

The metabolic differences relate to how well each group can use insulin to promote glucose uptake by the cells for storage and energy use. People who are ‘early birds’ (individuals who prefer to be active in the morning) rely more on fat as an energy source and are more active during the day with higher levels of aerobic fitness than ‘night owls’. On the other hand, ‘night owls’ (people who prefer to be active later in the day and night) use less fat for energy at rest and during exercise.

Researchers from Rutgers University, New Jersey, USA classified participants (n=51) into two groups (early and late) based on their ‘chronotype’ – our natural propensity to seek activity and sleep at different times. They used advanced imaging to assess body mass and body composition, as well as insulin sensitivity and breath samples to measure fat and carbohydrate metabolism.

Participants were monitored for a week to assess their activity patterns across the day….