DETERMINANTS OF CHANGE IN BLOOD-PRESSURE DURING SWEAT - THE SEDENTARYWOMEN EXERCISE ADHERENCE TRIAL

1. In a long-term study of the optimal approach to initiating and main taining a regular exercise programme in previously sedentary older wom en (40-65 years), we have assessed determinants of change in resting b lood pressure (BP) after 6 and 12 months, 2. Women (n = 126) were rand omly assigned to either a centre-based or home-based exercise programm e for an initial 6 months, The centre-based group attended supervised sessions three times per week, while the home-based group exercised un supervised at home three times per week, Both groups were home-based d uring a second 6 months. Within each arm, subjects were further random ized to either exercise at moderate intensity (40-55% heart rate reser ve; HR(res)) or at vigorous intensity (65-80% HR(res)). A nonintervent ion comparison group of 30 women was followed throughout, 3. At 6 mont hs there was a fall in BP with moderate, but not vigorous intensity ex ercise(-2.7 mmHg; P = 0.025), an effect no longer significant at 12 mo nths, 4. Change in BP was unrelated to improvements in fitness (VO2max ), increases in lean tissue mass, number of exercise sessions complete d or a composite measure of the total number of exercise sessions comp leted multiplied by the mean exercise intensity expressed as a percent age of heart rate reserve (%HR(res)). 5. Continuing participation in a ny regular exercise was a consistent predictor of change in BP, with t hose subjects still exercising in the 2 weeks before BP measurement ha ving 1.9 mmHg lower BP at 6 months (P = 0.038) and 3.8 mmHg lower BP a t 12 months (P = 0.016). 6. We conclude that the small effects of exer cise on resting BP in these older women are predominantly related to c ontinuing participation in lower intensity exercise, rather than to im provements in fitness or body composition.