DISPARATE EFFECTS OF EXERCISE TRAINING ON GLUCOSE-TOLERANCE AND INSULIN LEVELS AND ON AMBULATORY BLOOD-PRESSURE IN HYPERTENSIVE PATIENTS

Objective: To assess the relationship of insulin levels and glucose to lerance to blood pressure in hypertension. Design: An open, prospectiv e trial of exercise training with ambulatory blood pressure monitoring and intravenous glucose tolerance testing before and after a 14-week training programme. Patients: Twenty sedentary, untreated, non-obese, normoglycaemic individuals of both sexes with uncomplicated essential hypertension, of whom 16 completed the study. Intervention: Fourteen w eeks of supervised, low-intensity, group exercise of three 1-h session s per week. Main outcome measures: Ambulatory and clinic blood pressur e, and glucose and insulin responses to an intravenous glucose toleran ce test. Results: Maximal work capacity on a bicycle ergometer increas ed by 20% (P < 0.001); 24-h ambulatory blood pressure was 143 +/- 12/8 7 +/- 5 mmHg before and 142 +/- 13/87 +/- 7 mmHg after training. Clini c blood pressure decreased from 166 +/- 14/103 +/- 5 mmHg to 157 +/- 1 2/99 +/- 6 mmHg (P < 0.03). Two-way analysis of variance indicated sig nificant decreases in both glucose (P < 0.04) and insulin (P < 0.03), fasting and throughout the intravenous glucose tolerance test. Conclus ions: Although mild exercise reduced clinic blood pressure significant ly, it did not affect ambulatory blood pressure despite a marked reduc tion in glucose and insulin levels. This finding argues against a dete rminant role of insulin in the 24-h maintenance of blood pressure in h ypertensive patients under the conditions of the study.