Ageing is associated with a progressive decrease in exercise capacity. This decrease can be attributed to loss of power generating capacity of the muscles and maximal aerobic capacity (VO_2max) as a consequence of muscle wasting, alterations in muscle contractile properties and cardiac function. It is to be expected that reduced activity levels at old age contribute to the age-related decrement in cardiovascular and muscle function. Master athletes are a unique population to study to what extent these changes are related to ageing per se, as they maintain a high level of physical activity and suffer less from co-morbidities than the normal ageing population (1). The importance of physical activity is readily seen in the higher power generating capacity of the muscle and VO_2max in master weight lifters (2) and endurance (3) athletes, respectively, than that in age-matched sedentary people. The elevated VO_2max in endurance trained master athletes is attributable to a larger stroke volume and maximal cardiac output (3). Nevertheless, master athletes show a similar age-related decline in muscle power and VO_2max as sedentary people (2,3). Part of this might be related to a diminished training stimulus to the heart and/or muscles as a consequence of the reduced training intensity at old age (3). Despite this age-related decline in performance, the VO_2max and muscle power of master athletes is similar to that of sedentary people up to 20 years younger. Hence, their quality of life is significantly better than that of other people of their age, which is further enhanced by diminished arterial stiffness and peripheral vasoconstriction (3), an improved glucose tolerance and lipid profiles similar to younger people (4). It is encouraging to note that at advanced age improvements in cardiovascular and muscle function can also be realised by short term training programmes (5,6). Similar to the decline in VO_2max and muscle power of master athletes, the response to training programmes may be attenuated at old age (7). In conclusion, the study of master athletes has taught us that life-long, or only recently started, exercise training in old age is an adequate means on improving the quality of life and to delay the decline in exercise performance in old age. It has also shown us that high activity levels do not entirely prevent the age-related reduction in muscle power and VO_2max. Thus the question remains as to the cause of the inherent loss of exercise capacity as a result, it appears, of the ageing process per se. Some of the factors associated with ageing are changes in circulating substances, such as hormones and cytokines, and the ongoing denervation-reinnervation process (7).