Training: How Muscles Maintain Health—"Strong Muscles" Boost Lifespan and Quality of Life

Muscles are more than just "organs for movement"; they function as "endocrine organs" that regulate overall health. During exercise, muscles secrete bioactive substances called myokines, which are involved in reducing inflammation, controlling blood sugar, improving fatty liver, enhancing brain plasticity, and boosting immune function. Observational studies and meta-analyses suggest that lower muscle strength and mass are associated with a higher risk of all-cause mortality, while approximately 60 minutes of resistance training per week is linked to a reduced risk of death. Additionally, higher cardiorespiratory fitness is progressively associated with lower long-term mortality rates. For the elderly, machine-based strength training is both safe and effective, significantly improving daily activities like standing up from a chair. From a nutritional perspective, due to age-related "anabolic resistance," a protein intake of 1.0 to 1.5 g per kg of body weight per day (with individual differences) is discussed as a recommended range, which, combined with exercise, helps maintain muscle mass. This article provides a comprehensive explanation for Japanese readers, covering the mechanisms of muscle health benefits, scientific evidence, a 4-week program that can be practiced starting today, and guidance on nutrition, sleep, and pain management to ensure safe and sustained practice.