Being an early riser or night owl could be a determining factor in enjoying good health, as a new study has found a link between an individual’s chronotype – lark or early riser, or owl or night owl – and their propensity to develop type 2 diabetes and cardiovascular disease . The body’s biological clock that controls our sleep and wake patterns affects most vital functions, and a group of researchers at Rutgers University (New Jersey, USA) has found that it also influences metabolism and alters our body’s preference for energy sources.
The results of the work have been published in Experimental Physiology and show that people who stay up later have a lower ability to use fat for energy, so fats can accumulate in their body and increase the risk of developing type 2 diabetes and cardiovascular diseases, which are chronic diseases associated with a high number of deaths worldwide.
The metabolic differences they found between the two groups related to how efficiently they could use insulin to promote glucose uptake by cells for energy storage and use. Individuals who are “early birds” (prefer to be active in the morning) rely more on fat for energy and are more active during the day with higher levels of aerobic fitness than “night owls” (those who prefer to be active later in the day). in day and night). Also, night owls use less fat for energy at rest and during exercise.
The time of going to sleep influences the metabolism of fats
The researchers classified the 51 adults who participated in the study into two groups (early and late) based on their chronotype, that is, their natural tendency 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.
Night owls are less able to use fat for energy, and fats can build up in your body and increase your risk of type 2 diabetes and cardiovascular problems
They monitored the participants for a week to assess their activity patterns throughout the day. These people ate a calorie- and nutrient-controlled diet and fasted overnight to minimize the impact of the diet on results. To study fuel preference, they were tested at rest before completing two 15-minute bouts of exercise: a moderate-intensity session and a high-intensity session on a treadmill. Aerobic fitness levels were assessed through an incline test in which the incline was raised 2.5% every two minutes until the participant reached the point of exhaustion.
The researchers found that early risers, or larks, use more fat for energy both at rest and during exercise than night owls. Early risers were also more sensitive to insulin. Night owls are insulin resistant, which means their bodies need more insulin to lower blood glucose levels, and their bodies prefer carbohydrates for energy over fat. Their reduced ability to respond to insulin to induce fuel use may be detrimental, indicating an increased risk of type 2 diabetes or heart disease.
The cause of this change in metabolic preference between early risers and night owls has not yet been discovered, so more research is needed. Professor Steven Malin of Rutgers University and lead author of the paper said: “The differences in fat metabolism between ‘early birds’ and ‘night owls’ show that our body’s circadian rhythm (wake/sleep cycle ) could affect the way our bodies use insulin. The ability to respond to the hormone insulin has important implications for our health. This observation advances our understanding of how our body’s circadian rhythms affect our health. Because chronotype appears to affect our metabolism and hormonal action, we suggest that chronotype could be used as a factor in predicting an individual’s risk of disease.”
“We also found that early risers are more physically active and have higher fitness levels than night owls, who are more sedentary during the day. More research is needed to examine the link between chronotype, exercise and metabolic adaptation to identify whether exercising earlier in the day has greater health benefits.”
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