Non-pharmacologic measures for lowering blood pressure

Effects of mental relaxation and slow breathing in essential hypertension

OBJECTIVES

To compare mental relaxation and slow breathing as adjunctive treatment in patients of essential hypertension by observing their effects on blood pressure and other autonomic parameters like heart rate, respiratory rate, peripheral skin temperature, electromyographic activity of the frontalis muscle and skin conductance.

METHODS

One hundred patients of essential hypertension either receiving antihypertensive drugs or unmedicated were selected randomly. Various parameters were recorded during the resting state and then during mental relaxation and slow breathing for 10 min each, separated by a quiet period of 15 min. All parameters were recorded again after mental relaxation and slow breathing. Changes in various parameters observed after mental relaxation and slow breathing were analyzed and compared.

RESULTS

Both mental relaxation and slow breathing resulted in a fall in systolic blood pressure, diastolic blood pressure, heart rate, respiratory rate and electromyographic activity with increase in peripheral skin temperature and skin conductance. Slow breathing caused a significantly higher fall in heart rate (p<0.05), respiratory rate (p<0.001), systolic blood pressure (p<0.05) and diastolic blood pressure (p<0.01). Increase in peripheral skin temperature (p<0.05) and reduction in electromyographic activity (p<0.05) occurred more with mental relaxation. No significant differences were seen between increases in skin conductance (p>0.2) observed with both the modalities.

CONCLUSIONS

Even a single session of mental relaxation or slow breathing can result in a temporary fall in blood pressure. Both the modalities increase the parasympathetic tone but have effects of different intensity on different autonomic parameters.

Short-term strenuous exercise training: effects on blood pressure and hormonal levels in mild hypertension

The effect of a six-week strenuous exercise training programme (modified Bruce protocol, treadmill, three times per week) on resting and exercising blood pressure, heart rate, plasma catecholamines, chromogranin A, renin activity and aldosterone levels was investigated in 15 patients with mild hypertension. An identical exercise test was conducted at baseline and study close (six weeks). At follow-up, seven to ten days after study close, patients completed an exercise test of equivalent intensity to that at baseline, achieving comparable heart rate levels at maximal exercise. On each occasion, blood pressure, heart rate and hormonal variables were measured at rest (supine), maximal exercise and ten minutes after stopping exercise. Resting and exercising blood pressure and heart rate were reduced by the six-week exercise regimen. There was a trend, although not statistically significant, for resting plasma noradrenaline levels to be lower at study close. The reduction in blood pressure and heart rate at maximal exercise was associated with a significant attenuation of the plasma renin response to exercise. Plasma catecholamines also appeared to be lower after exercise training, although this effect was not statistically significant. Plasma levels of chromogranin A and aldosterone measured at rest and maximal exercise were not influenced by the exercise regimen. Further controlled studies are required to corroborate the results of this preliminary study.

The Challenge of Hypertension to South African Health Psychology. 1. The Potential Contribution of Educational, Cognitive and Behavioural Strategies to Prevention and Treatment

This is the first of two papers on the potential contribution of health psychology to alleviating the problem of hypertension in South Africa. Educational, cognitive and behavioural strategies that can be employed as an adjunct to, or in place of, medication include: improving patients’ adherence to treatment regimens; educating and training in weight reduction, smoking cessation; healthy dietary and exercise habits; and a range of cognitive and behavioural stress management techniques. Research is reviewed, mostly from Europe and the USA, evaluating the effectiveness of these strategies, and their current status relative to the use of medication is examined.

Enalapril versus combined enalapril and nadolol treatment: effects on blood pressure, heart rate, humoral variables, and plasma potassium at rest and during exercise in hypertensive patients

The effect of enalapril alone and in combination with nadolol on resting and exercising blood pressure, heart rate, plasma renin activity, aldosterone, noradrenaline, and potassium levels was studied in 10 hypertensive patients (diastolic blood pressure between 95 and 114 mmHg). Patients received placebo for 4 weeks, enalapril (mean daily dose 24.5 mg) for 8 weeks, and nadolol, 40 mg once daily, was added for the remaining 8 weeks of the study. Exercise testing (modified Bruce, treadmill) was conducted at the end of the placebo run-in phase and at the end of each treatment period. Enalapril reduced resting and exercising blood pressure independent of any change in heart rate: This effect was increased with combination treatment. Plasma renin activity at rest and during exercise was increased by enalapril. Combination treatment attenuated this response and significantly reduced plasma aldosterone. Neither treatment had any effect on plasma noradrenaline levels. Resting plasma potassium levels were increased with combination treatment, whereas both treatment regimens increased plasma potassium levels during exercise. There were no clinically relevant episodes of hyperkalemia. Further investigation is required to qualify the nature of the blood pressure and plasma potassium response with combination treatment.