Ten men with uncomplicated essential hypertension (mean standing blood pressure 165/109 mm Hg) and 10 normal controls matched for age and weight were studied for the hypotensive potential of moderate exercise. Tests were conducted on a treadmill set to induce a steady heart rate of 120 beats/min and performed over five 10-minute periods separated by three minutes' rest and finishing with 30 minutes' sitting quietly in a chair. During exercise the mean systolic pressures were identical in the hypertensive patients and controls (175±SEM 5 mm Hg), the controls therefore sustaining an appreciably greater increase in pressure. During the 30-minute rest period after the tests both the control and hypertensive groups showed a significant and sustained fall in absolute systolic pressures as compared with pre-exercise values (p <0·001), the mean percentage reductions being 22% and 25% respectively. If a fall in blood pressure after exercise is maintained for four to 10 hours, then a “good walk” twice a day might be reasonable treatment for mild hypertension. Studies are continuing to determine the amount of exercise needed and the duration for which the reduction in blood pressure is maintained.

Tyne1 Eight men with primary hypertension were treated for 3 weeks with placebo, epanolol (200 mg or 400 mg), or atenolol 100 mg in a randomised cross-over study. Each active treatment period was preceded by a 3 week placebo treatment period and both investigators and subjects were blind to the active drug sequence. 2 At the end of each period, measurements were made of resting cardiovascular (heart rate, blood pressure, forearm blood flow) and biochemical variables (plasma renin, angiotensin II, aldosterone, adrenaline, noradrenaline, vasopressin, sodium and potassium concentrations and osmolality). Responses to exercise (including gas exchange, sweat rate, and ratings of perceived exertion) and the reflex cardiovascular adjustments to distal body subatmospheric pressure were also assessed. 3 The reduction of exercise-induced tachycardia by epanolol 400 mg was comparable to that of atenolol. There was very little difference in the effects of atenolol or epanolol 400 mg on resting blood pressure, but in both cases blood pressures were usually significantly lower than with epanolol 200 mg. 4 Although each active treatment influenced the renin-angiotensin system and circulating levels of catecholamines, the exercise-induced reduction in blood pressure was unaffected. Thus, the hypotensive effects of pharmacological and non-pharmacological interventions were additive.

1 We have studied the physiological responses to 50 min of intermittent, moderate exercise in hypertensive men after the ingestion of a single dose of placebo, propranolol or metoprolol, and also after 28 days treatment. In addition, subjective assessments of mood were made during the last 7 days of each period of chronic treatment. 2 Heart rate and blood pressure, both at rest and during exercise, were significantly reduced by a single dose of propranolol or metoprolol; more marked effects were observed after chronic treatment. 3 Ventilation and gas exchange during exercise were only slightly disturbed by single doses of propranolol or metoprolol, whereas chronic treatment had no effect. 4 Perceived exertion scores were increased after a single dose of either drug, compared to placebo, and the effect of propranolol was greater than that of metoprolol. With chronic treatment there were fewer differences between the perceived exertion scores during exercise, although 'leg' fatigue remained greater after propranolol than after placebo. 5 Sweating from the forehead during exercise was enhanced by a single dose of either f3-adrenoceptor antagonist, with propranolol having the greater effect. After chronic treatment the effect of propranolol was diminished, whereas the effect of metoprolol was maintained. 6 Very few disturbances of mood were found after chronic ingestion of the f8-adrenoceptor antagonists.

We have studied the effects of single oral doses of, and of 28 days treatment with, placebo, propranolol or metoprolol, on the metabolic and hormonal responses to prolonged exercise in hypertensive men. Blood glucose levels fell during exercise on all occasions. No additional effects of the beta‐adrenoceptor antagonists, compared to placebo, were observed. The exercise‐induced increase in plasma potassium was enhanced after a single dose of propranolol or metoprolol, and also after chronic treatment with propranolol. Chronic treatment with either drug led to an increase in plasma potassium levels at rest. The growth hormone response to exercise was potentiated by a single dose of metoprolol or propranolol, and after chronic treatment with the drugs. A single dose of propranolol (but not metoprolol) was associated with a marked increase in plasma cortisol and adrenaline levels during exercise. After chronic treatment no such increase occurred. In both the acute and chronic phases of the study, blood lactate levels were higher during exercise in the presence of either propranolol or metoprolol compared to placebo, whereas non‐esterified fatty acid levels were lower. A single dose of metoprolol produced a significantly greater reduction in blood glycerol levels during exercise than a single dose of propranolol. After chronic treatment, both propranolol and metoprolol produced similar reductions in blood glycerol levels during exercise. After a single dose, both drugs significantly augmented the increase in plasma noradrenaline levels during exercise. A similar effect was seen after chronic treatment.

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