Role of (epi-)genetics in lifestyle and training-induced responses in muscular fitness.

Age-related decline in muscular fitness leads to high degrees of frailty. As our Western society is getting increasingly old, this is associated with high healthcare costs. However, loss of muscle mass and function with age is individually different which places a part of older individuals at high risk for sarcopenia at an earlier age. Similarly, high interindividual differences are observed in the responses of muscle to (resistance) exercise, an important intervention strategy to partially reverse muscular fitness deterioration. The additional role of epigenetic modifications – besides DNA-sequence variation – in explaining health-enhancing responses to strength training is not yet explored. This study will be the first to shed light on the temporal and dynamic changes in DNA methylation as induced by resistance exercise in an acute and long-term training and de-/retraining intervention study in elderly in an accessible peripheral material (whole blood). Furthermore we will identify the role of DNA methylation modifications in a natural 10-year aging design related to muscle mass and strength. Identification of methylation profiles predicting resistance exercise-induced and aging-induced changes in muscular strength might be used as biomarkers to identify high and low responders and risk for sarcopenia. Knowledge of exercise-induced methylation plasticity is crucial in any clinical study investigating pharmacological or therapeutically induced methylation changes.