Exercise is not regarded as a major risk factor for ischaemic heart disease (IHD). Nevertheless, physically active individuals have a lower risk than their sedentary counterparts, possibly because of favourable modifications of lipoprotein metabolism. In particular, endurance‐trained men and women have markedly higher concentrations of high‐density lipoprotein cholesterol than sedentary controls. Although the results of exercise intervention studies are less consistent than cross‐sectional observations, many do show an increase in high density lipoprotein cholesterol with training. However, most studies have involved high‐intensity exercise, usually running, and adherence to these sort of training regimens is poor. Exercise will only influence the risk of IHD in the population if the amount and type of exercise needed to confer benefit is attractive and attainable to large numbers of people. Consequently, there is a need to examine the potential of more socially acceptable, low‐intensity exercise to influence risk factors for IHD. In a study at Loughborough University 42 women (mean age 44.9 years) were studied for one year. Twenty‐eight followed a programme of brisk walking, whilst 16 acted as controls. After 12 months the walkers showed an 11% increase in maximal oxygen uptake (Mean±s.e.m.) (26.7±‐0.7 ml/kg/mincf. 29.7±0.8 ml/kg/min, P<0.01) but no change in body mass or the sum of four skinfolds. Plasma total cholesterol was not significantly different at 12 months for either group but walkers showed a 27% increase in plasma high‐density lipoprotein cholesterol (1.17 ± 0.08 mmol/lcf. 1.49±0.06 mmol/l, P<0.01). Brisk walking was therefore a sufficient exercise stimulus to improve fitness and influence lipoprotein metabolism in these previously sedentar