17 Oct Early chronotypes and metabolic syndrome
All hormones have circadian rhythms, but not all humans lead the same circadian life. Some people identify themselves as early birds, humming birds or night owls. So, what is Chronotype? this is a circadian classification identifying the preference of an individual to perform an activity or acknowledge alertness during different periods of the day.
New research published in Experimental Physiology found wake/sleep cycles cause metabolic differences and alter our body’s preference for energy sources. The researchers said that Early chronotypes (ECs) are often insulin-sensitive, in part, due to physical activity behaviour. Nevertheless, it was unclear, if chronotypes differ in resting and/or exercise fuel oxidation in relation to insulin action, whichwas the aim of this investigation.
Researchers used the Morningness – Eveningness Questionnaire (MEQ) in 51 participants, they classified into two groups (early and late) based on their chronotype. 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. They ate a calorie and nutrition-controlled diet and had to fast overnight to minimise dietary impact on the results. To study fuel preference, they were tested while at rest before completing two 15-minute bouts of exercise: one moderate and one high intensity session on a treadmill. Aerobic fitness levels were tested through an incline challenge where the incline was raised 2.5% every two minutes until the participant reached a point of exhaustion. They 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 main finding and its importance were that early chronotypes with metabolic syndrome utilized more fat during rest and exercise independent of aerobic fitness when compared with late chronotypes. Early chronotypes were also more physically active throughout the day. Greater fat use was related to non-oxidative glucose disposal. These findings suggest that early chronotypes have differences in fuel selection that associate with type 2 diabetes risk.
In addition, ECs engaged in less sedentary behaviour throughout the day and performed more Physical activity in the morning and midday than Later chronotypes (LCs). These observations may have public health significance as more Late Psychical activity paralleled higher in ECs as well as being directly correlated with elevated metabolic insulin sensitivity. Thus, individual preference for engaging in activity during the earlier parts of the day may favourably impact metabolic health.
References
- Malin,S.K.,Remchak,M.M.E.,Smith,A.J.,Ragland,T.J.,Heiston,E.M.,&Cheema,U.(2022). Early chronotype with metabolic syndrome favours resting and exercise fat oxidation in relation to insulin-stimulated non-oxidative glucose disposal. Experimental Physiology, 1–10. https://doi.org/10.1113/EP090613
- The Physiological Society. “People who are ‘night owls’ could have greater risk of type 2 diabetes and heart disease than those who are ‘early birds’, study finds.” ScienceDaily. ScienceDaily, 20 September 2022. sciencedaily.com/releases/2022/09/220920100754.htm
- This article references artist Gemma Correll’s popular comic, shown. You can see more of her work on her website https://www.gemmacorrell.com/