Can physical activity ameliorate immunosenescence and thereby reduce age-related multi-morbidity?

Remodelling of the immune system with age - immunosenescence - is a substantial contributor to poor health in older adults, with increasing risk of infections, cancer and chronic inflammatory disease contributing to age-related multi-morbidity. What is seldom considered when examining the immune response of an aged individual is that the immune system is profoundly influenced by physical activity. Habitual physical activity levels decline with age, with significant consequences for muscle mass and function. Skeletal muscle is a major immune regulatory organ and generates a range of proteins, termed myokines, which have anti-inflammatory and immunoprotective effects. Several studies indicate that maintaining physical activity has immune benefits in older adults, for example, it reduces the systemic inflammation associated with chronic age-related diseases. Here, we discuss how physical activity can prevent or ameliorate age-related multi-morbidity by boosting immune function, and we consider whether physical activity could improve immunotherapy outcomes in age-related conditions such as cancer.