Does it matter if you wake up early and get moving versus sleeping in later, staying up later, and getting going later? There are different patterns people prefer, often called chronotypes. Is the Early Chronotype healther?
A study published in the journal Experimental Physiology highlights that people with early chronotype use more fat during rest and exercise and exhibit more sensitivity to insulin. They remain more physically active throughout the day and have a lower risk of type 2 diabetes. In the current study, scientists have evaluated the dynamics of energy metabolism among early and late chronotypes during rest and exercise.
Study details
The study population included 51 adults with metabolic syndrome. Metabolic syndrome is a cluster of conditions that occur together, increasing your risk of heart disease, stroke and type 2 diabetes. These conditions include increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol or triglyceride levels.
The study subjects were categorized as early chronotypes (n=24) or late chronotypes (n=27) based on their response to a Morningness–Eveningness questionnaire.
The Energy metabolism preferences of the participants were assessed by allowing them to perform moderate-to-high intensity exercise on a treadmill.
Important findings
The analysis of metabolic parameters revealed that early chronotypes have higher VO2max (maximum oxygen utilization during exercise) and non-oxidative glucose disposal than late chronotypes.
The level of physical activity was higher among early chronotypes. They were more active in the morning and midday compared to late chronotypes.
At resting conditions, early chronotypes showed higher fat oxidation than late chronotypes. During moderate and high-intensity exercises, both groups exhibited increased carbohydrate oxidation. However, early chronotypes maintained a higher level of fat oxidation during all exercise conditions.
During moderate exercise, the maximum oxygen utilization correlated significantly with fat oxidation and metabolic flexibility (carbohydrate or fat preference). A significant correlation was also observed between body mass index (BMI) and afternoon sedentary behavior.
Both body weight and insulin sensitivity significantly correlated with light physical activity. Notably, a significant correlation was observed between fat oxidation and non-oxidative glucose disposal during high-intensity exercise.
Study significance
The study reveals that early chronotypes with metabolic syndrome utilize more fat during rest and exercise than their late chronotype counterparts. This metabolic activity in early chronotypes does not depend on the level of physical fitness and light physical activity per day.
Early chronotypes also have higher insulin sensitivity than late chronotypes, reducing their susceptibility to type 2 diabetes. They remain less sedentary throughout the day and perform more physical activity in the morning and midday, which further help improve metabolic insulin sensitivity.
Although both early and late chronotypes can shift fuel preference toward carbohydrate oxidation during exercise, late chronotypes prefer carbohydrates over fat as an energy source.
Professor Steven Malin from Rutgers University, New Jersey, a senior author on the study, said,
Night owls are reported to have a higher risk of obesity, type 2 diabetes, and cardiovascular disease when compared with early birds. A potential explanation is they become misaligned with their circadian rhythm for various reasons, but most notably among adults would be work.”
The Bottom Line
If you can develop the habit, or maintain the habit, of going to bed early, getting 7-8 hours of high-quality sleep, and getting up refreshed at sunrise to start activities, it may favor better metabolic health, fitness, and a lower risk of diabetes type 2.
