Effects of Chrono-Exercise and Chrono-Nutrition on Muscle Health: Understanding the Molecular Mechanisms Activated by Timed Exercise and Consumption of Proteins and Carbohydrates.

The circadian clock is an endogenous timekeeping system that regulates various physiological and behavioral processes. Recently, it has been shown that the timing of physical activity and food intake can significantly influence metabolic muscle health. Some recent clinical evidence has shown that physical activity practiced in the late afternoon can be more effective in terms of performance and muscle strength. Preclinical studies have highlighted that the explanation for this effect lies in the different daily expression in the muscle of clock genes and clock-controlled genes involved in muscle development and hypertrophy. In conjunction with scientific advances in understanding the molecular mechanisms that regulate circadian rhythms and muscle trophy, chrono-nutrition has gained scientific resonance and has become a promising field, aimed at understanding the regulation of body metabolism. Clinical and preclinical studies have shown that protein consumption at specific circadian time points during the day, or precisely after exercise, can activate signaling pathways involved in muscle protein synthesis and, thus, favor skeletal muscle mass development as well as mitochondrial biogenesis, thereby improving skeletal muscle cell energy production and function. On the other hand, some studies have shown that the consumption of carbohydrates immediately after exercise increases insulin secretion, which facilitates glucose uptake by muscle cells to replenish glycogen. This review summarizes the current scientific literature concerning chrono-exercise and chrono-nutrition and muscle health, focusing on molecular mechanisms involving the circadian regulation of muscle mass, strength, and health. Understanding the intricate molecular relationship between circadian rhythms, exercise, nutrition, and muscle metabolism is essential for optimizing nutritional strategies to prevent or treat muscle wasting. In addition, tailoring protein and carbohydrate intake to timing and individual needs can improve muscle maintenance, growth, and performance.