Myokine response to resistance exercise and training in older adults: implications for healthy ageing

In response to exercise, skeletal muscle produces myokines, allowing crosstalk between the muscle and other organs, including the brain. The emerging role of myokines to mediate cognitive and physical gains seen in exercise suggests that myokines may be valuable biomarkers for monitoring exercise prescription for people with, for example, cancer, diabetes, or neurodegenerative diseases. This is of particular interest in healthy ageing. Muscle quality (MQ) and its decline in older adults, exacerbated by chronic inflammation and elevated cytokine levels, significantly impacts health and functional independence. This deterioration, coupled with unfavourable body compositional changes, can lead to increased frailty, a higher risk of falls, and a greater incidence of chronic diseases due to chronic low-grade systemic inflammation from pro-inflammatory cytokines. Muscle quality, a biomarker of muscle health, may predict myokine production, which exerts anti-inflammatory actions that counteract chronic inflammation. Resistance training (RT), particularly at higher intensities, may enhance muscle quality and reduce inflammation in older adults if adhered to long-term. However, the relationship between muscle quality and myokine expression remains unclear, and research on the acute inflammatory response to resistance exercise in healthy older adults is still inconclusive. This thesis explored inflammatory marker responsiveness to resistance exercise and training and its relationship to muscle quality.