The Significant Role of Physical Activity and Exercise in Health and Metabolic Diseases

Physical inactivity, which currently dominates the lifestyles of most people, is linked to chronic metabolic diseases such as obesity, type 2 diabetes (T2D), hypertension, metabolic syndrome, and cardiovascular disease, all of which share insulin resistance as a common pathogenic mechanism. Both epidemiological and experimental intervention studies have consistently shown that physical activity and exercise can reduce the incidence of these diseases and significantly improve their clinical outcomes, resulting in enhanced quality of life and well-being. This approach includes various forms of aerobic and anaerobic/resistance training, either individually or in combination, leading to reduced insulin resistance and visceral fat, regardless of the weight loss achieved through diet. It also lowers inflammatory responses and oxidative stress, a harmful mechanism that leads to cellular damage, and positively impacts immunological regulation. Regarding timing, physical activity/exercise appears to produce better outcomes for metabolic control, particularly in individuals with T2D, when performed after dinner compared to other times of the day. In addition to organized physical activity/exercise sessions, practices such as interrupting prolonged sitting with frequent breaks every 30 min that involve muscular contractions and increased energy expenditure may also benefit metabolic health. Minimizing physical inactivity, prolonged sitting at work or during leisure time, can decrease the frequency of metabolic illness, enhance health and quality of life, and avert premature death. However, intense exercise may not always be the most beneficial option for health, and the relationship between adverse events and the intensity of physical activity or exercise resembles a U-shaped or J-shaped curve. Physical activity/exercise should be performed at a suitable intensity that aligns with personal capability. In this primarily clinically focused review, we discuss the effects of insulin on target tissues, the significance of insulin sensitivity in metabolic regulation, how physical inactivity contributes to insulin resistance, the different types of exercise and their impact on insulin effectiveness, and the importance of physical activity and exercise in managing metabolic diseases.