Hypertension was detected in 56 of 436 women and 34 of 371 men in an urban population sample of 47-54-year-old individuals. The prevalence of glucose intolerance according to WHO criteria was 22.2% in the hypertensive group and 4.3% among the normotensives, with mean 2-hour blood glucose values of 5.8 and 4.4 mmol X 1(-1), respectively. The difference in mean 2-hour blood glucose was independent of body mass index, physical activity during leisure time or at work, age and smoking in covariance analysis. Subjects with high physical leisure time activity (n = 125) had a lower mean blood pressure and a lower prevalence of hypertension, 4.8%, than those with low activity (n = 682), 12.3%. The increase in diastolic blood pressure in the latter group and the male subgroup appeared to be independent of body mass index, physical job activity, age and smoking. Multiple regression analyses with blood pressure as dependent variable and six metabolic and clinical characteristics as predictors identified 2-hour blood glucose and body mass index as the most important predictors. Physical leisure time activity was associated with diastolic blood pressure, however only when 2-hour blood glucose was not included as predictor. Thus, physical activity may exert an influence on the blood pressure level mainly through changes in glucose tolerance and/or body weight, although alternative mechanisms cannot be excluded.