Weight loss beat salt cuts for lasting blood pressure drops

Raised blood pressure sits behind a huge share of heart disease and stroke, and the usual advice list is familiar: lose weight, cut salt, move more, manage stress, drink less. What was far less clear when this review was conducted is whether changing those habits actually keeps blood pressure down over the long haul, rather than nudging it briefly. Plenty of short trials existed, but a reading that lasts a few weeks says little about an effect you would need to hold for years. This review set out to find which non-drug approaches have evidence of sustained effect, and how big that effect really is.

The authors systematically searched MEDLINE from 1966 to April 1995 for randomised controlled trials of single lifestyle interventions in adults aged 45 or older, both with and without hypertension. Crucially, they only kept trials with at least six months of follow-up, which excluded the majority of studies on the grounds that short trials say nothing about sustainability. That left eight trials of salt restriction, eight of weight reduction, eight of stress management, eight of exercise, and a single trial of alcohol reduction. For each intervention they calculated the net change in systolic blood pressure, meaning the change in the intervention group minus the change in the control group.

In people with hypertension, weight loss produced the largest sustained net drop in systolic pressure at 5.2 mmHg, followed by salt restriction at 2.9, stress control at 1.0 and exercise at just 0.8, with the latter three estimates uncertain enough that a true effect of zero could not be ruled out. In people with normal blood pressure the changes were smaller still: 2.8 mmHg for weight loss, 1.3 for salt restriction, 2.1 for alcohol reduction and 0.2 for exercise. The authors also flagged that most trials were of low methodological quality, that bias often tended to inflate the changes observed, and that few trials controlled for participants simultaneously changing other blood pressure risk factors.

This review complicates the comfortable assumption that every item on the standard lifestyle list earns its place equally. The evidence for sustained effects turned out to be thin, uneven across interventions, and gathered largely from weak trials, with some combinations, such as stress control in people with normal blood pressure, simply never studied over the long term. The authors' own conclusion is that the pooled figures are probably overestimates, and they call for large, long-duration trials in both hypertensive and normotensive people to pin the effects down properly. The open question it leaves is not whether lifestyle matters, but how much of the commonly quoted benefit survives beyond six months.

For a reader hoping to manage blood pressure through habits rather than prescriptions, this is a reason to weight the options rather than treat them as interchangeable: in this evidence, losing excess weight carried the most sustained effect, while salt restriction, stress management and exercise showed smaller and less certain changes over six months or more. It is equally a reason for realistic expectations, since even the best-performing intervention produced a modest average drop and the reviewers suspect the true figures are smaller. None of this says exercise or salt reduction are pointless, only that their sustained blood pressure effects were poorly demonstrated in the trials available here. Anyone with diagnosed hypertension is still in the territory of decisions made with a doctor, not a fact card.