Individuals who are "early birds" rely mostly on fat for energy and are more energetic during the day with greater levels of aerobic capacity versus "night owls."
Compared to night owls, early birds consume more fat for energy during both rest and exercise. Early risers are also more insulin sensitive, whereas late nighters are more insulin resistant, requiring more insulin to reduce blood sugar levels and favouring the consumption of carbs over fats.
A recent study discovered that wake/sleep cycles modify our body's preference for energy sources and induce metabolic variations.
The capacity to use fat as fuel is decreased in those who stay up longer, which means that fats may accumulate in the body and raise the risk of type 2 diabetes and cardiovascular disease.
The ability of each group to employ insulin to encourage glucose absorption by the cells for storage and energy consumption is related to metabolic differences.
On the other side, those who like to be active during the day and at night are described as "night owls" and they utilize less fat for energy both while relaxing and when active.
Participants (n=51) were divided into two groups (early and late) by researchers from Rutgers University in New Jersey, USA, based on their "chronotype" (our innate predisposition to seek activity and sleep at various times).
Advanced imaging, insulin sensitivity, and breath samples were all employed to analyse the metabolism of fat and carbohydrates as well as body mass and composition. A week of participant monitoring was used to evaluate the participants' daily activity habits. For the results to be as unaffected by diet as possible, they don't eat over night while eating a meal with restricted calories and nutrients. Before engaging in two 15-minute sessions of moderate and high intensity treadmill activity, individuals were evaluated at rest to determine their preferred fuel.