How to lower blood pressure naturally: what works and by how much

If you have been told your blood pressure is high or borderline, the changes with the strongest trial evidence are eating less salt, losing weight if you are overweight, exercising regularly, and drinking less if you take more than a couple of drinks a day. Each one lowers the top number, the systolic pressure, by a few points on average. Add a DASH-style diet built on fruit, vegetables and low-fat dairy, and the drop in people with hypertension ran into double figures in both DASH feeding trials. None of it replaces a GP check, and if your readings are high enough you will be offered medicine alongside the changes rather than instead of them.

Here is the ranking by average fall in systolic pressure, in mmHg, the unit blood pressure is measured in. The drops are consistently bigger in people who already have high blood pressure than in people with borderline readings, so each entry says which group the figure is for and how long the trials ran:

• DASH diet plus low salt: 11.5 mmHg in people with hypertension, 7.1 mmHg in people without, after 30 days at each salt level with all food supplied (NEJM)
• Isometric exercise such as wall squats: 8.24 mmHg, all participants, trials of 2 weeks or more (Br J Sports Med)
• DASH diet on its own: 6.74 mmHg, all participants, across 17 trials (Nutr Metab Cardiovasc Dis); 11.4 mmHg in people with hypertension in the original feeding trial (NEJM)
• Losing more than 5 kg: 6.63 mmHg, all participants (Hypertension)
• Halving heavy drinking: 5.50 mmHg in people on six or more drinks a day, trials of at least 7 days (Lancet Public Health)
• Cutting salt by 4.4 g a day: 4.18 mmHg, all participants, 5.39 mmHg in people with hypertension, trials of 4 weeks or longer (Cochrane)
• Aerobic exercise: 4.49 mmHg, all participants, trials of 2 weeks or more (Br J Sports Med)

What counts as high blood pressure, and why do a few points matter?

The HSE calls blood pressure high at 140/90 mmHg or higher when measured in a clinic, or an average of 135/85 mmHg from home readings. Ideal blood pressure is usually considered to be between 90/60 and 120/80. If you are over the age of 80, high blood pressure is 150/90 or higher in clinic, or an average of 145/85 at home (HSE). The first number, systolic, is the pressure when the heart beats. The second, diastolic, is the pressure between beats. Nearly all the figures in this piece are for the systolic number.

High blood pressure does not usually have any symptoms (HSE), which is why so many people have it without knowing. The Irish Longitudinal Study on Ageing (TILDA) reports that hypertension among over-50s rose from 63% to 71% over 12 years, and only 56% of those who had it were aware of it (TILDA). The same analysis, drawn from more than 8,000 TILDA participants, found 62% of over-50s with high blood pressure were not appropriately managed, meaning undiagnosed, untreated, or treated but not controlled. That is approximately 445,000 people.

A few points matter because risk tracks pressure. A meta-analysis of 123 drug trials with 613,815 participants found that every 10 mmHg reduction in systolic pressure significantly cut major cardiovascular events, coronary heart disease, stroke and heart failure, and led to a 13% reduction in deaths from any cause (Lancet). Those trials lowered pressure with tablets, so applying the same percentages to a drop earned through salt or exercise is an extrapolation. It is still the best estimate available.

How much does cutting salt lower blood pressure?

Salt is the best-studied change. A Cochrane review of 34 randomised trials with 3230 participants, each lasting at least 4 weeks, found that cutting salt by 4.4 g a day lowered blood pressure by 4.18 mmHg systolic and 2.06 mmHg diastolic on average (Cochrane). The effect was bigger in people who already had high blood pressure, at 5.39 mmHg systolic, and smaller in people with normal pressure, at 2.42 mmHg. The more you cut, the more it falls: a 6 g/day reduction was associated with a 5.8 mmHg fall in systolic pressure, though with a wide margin of error.

A larger meta-analysis in the BMJ, covering 133 trials, found much the same average of 4.26 mmHg systolic and adds a useful point: trials shorter than 15 days showed less than half the effect seen in longer ones (BMJ). So a fortnight of low-salt cooking that shows nothing on your monitor is not proof it does not work.

For scale, the Food Safety Authority of Ireland puts average adult salt intake at approximately 10g a day, though that figure comes from an older review (FSAI). The HSE target is less than 6g a day, about a teaspoon (HSE). The Cochrane authors go further and say a population target of 3 g a day should become the long-term aim. A separate dose-response analysis in Circulation, pooling 85 trials with sodium intakes from 0.4 to 7.6 g a day, found an approximately linear relationship between sodium and blood pressure with no flattening at the lowest intakes (Circulation). That is a statistical fit across trials rather than a trial of very low intakes, so it shows the trend continues, not that you should aim for the bottom of the range.

How much does losing weight lower it?

This one only applies if you are carrying extra weight. A meta-analysis of 25 randomised trials with 4874 participants found that losing an average of 5.1 kg, through eating less, moving more or both, lowered systolic pressure by 4.44 mmHg and diastolic by 3.57 mmHg (Hypertension). Per kilogram lost, that works out at 1.05 mmHg systolic. The trials where people lost more than 5 kg saw a 6.63 mmHg systolic drop, against 2.70 mmHg where they lost less.

The per-kilogram figure is an average across many people, not a promise for any one person, and the trials behind it were published between 1966 and 2002. But the direction is not in doubt, and it is one of the changes where a bigger effort gives a clearly bigger return.

Which kind of exercise works best, and by how much?

The largest analysis, 270 randomised trials, found every type of exercise lowers resting blood pressure (Br J Sports Med). Aerobic exercise such as walking, cycling or running gave a 4.49 mmHg systolic drop, weights or resistance training 4.55 mmHg, aerobic and weights combined 6.04 mmHg, high-intensity intervals 4.08 mmHg, and isometric exercise 8.24 mmHg. Isometric means holding a static position under tension, and the wall squat came out as the single most effective sub-type for systolic pressure.

Read the isometric ranking with some care. It is based on a statistic called SUCRA, which is the probability that a given exercise type is the most effective, not a measure of how much bigger its effect is. The authors themselves say the results should inform future exercise guidelines rather than stand as guidance now. HSE advice remains at least 150 minutes of moderate-intensity aerobic activity every week (HSE). The practical reading is that any regular exercise you will actually keep up is worth a few points, and a few minutes of wall squats a day costs nothing to add.

One safety line. Holding a static squat pushes blood pressure up while you hold it, and the trials say nothing about people with uncontrolled or very high readings. If your readings are well above 160/100 or you have heart disease, check with your GP before starting isometric training (HSE).

Does cutting back on drink make a difference?

Only if you drink a fair amount. A meta-analysis of 36 trials with 2865 participants found that in people who drank two or fewer drinks a day, cutting back was not associated with a significant reduction in blood pressure (Lancet Public Health). Above two drinks a day it was, and in those on six or more drinks a day who cut their intake by about 50%, systolic pressure fell by 5.50 mmHg and diastolic by 3.97 mmHg. Two caveats: a drink in that analysis was 12 g of pure alcohol, larger than the Irish standard drink, and 2464 of the 2865 participants were men.

In Ireland a standard drink has 10g of pure alcohol: half a pint of beer, stout or cider, a small 100ml glass of wine or a single 35.5ml measure of spirits (HSE). The HSE low-risk guideline is no more than 11 standard drinks a week for women and 17 for men, with at least 2 to 3 alcohol-free days a week. If you are inside those limits, the trial evidence suggests drink is not the lever to pull for your blood pressure. If you are well outside them, it may be the biggest one.

Does the DASH diet add anything beyond salt, and do the changes add up?

DASH stands for Dietary Approaches to Stop Hypertension: a pattern rich in fruit, vegetables and low-fat dairy, with less saturated fat. In the original trial, 459 adults were fed the diet for eight weeks with sodium intake and body weight held steady, so the effect is separate from either. It lowered systolic pressure by 5.5 mmHg more than a typical diet, and by 11.4 mmHg among the 133 participants who had hypertension (NEJM). Participants without hypertension got 3.5 mmHg.

Later meta-analyses disagree on the size. One of 17 trials put the average at 6.74 mmHg (Nutr Metab Cardiovasc Dis). A larger one of 30 trials with 5545 participants found 3.2 mmHg (Adv Nutr), and noted the diet worked better in trials where people were eating a lot of sodium to begin with. A network meta-analysis comparing 22 lifestyle interventions still ranked DASH first, at 6.97 mmHg over usual care (J Am Heart Assoc). The honest range is wide, but the diet is consistently near the top.

The DASH-Sodium trial is the one that tested two changes together. With 412 participants eating supplied food at high, medium and low salt levels for 30 days each, the DASH diet with low salt gave a systolic pressure 11.5 mmHg lower than a typical high-salt diet in people with hypertension, and 7.1 mmHg lower in people without (NEJM). But the gains overlap. Going from medium to low salt cut a further 4.6 mmHg on a typical diet and only 1.7 mmHg on top of DASH. So the effects do add up, but you cannot simply sum the numbers from each section above. Both DASH trials also supplied every meal, so results with your own shopping and cooking will be smaller.

How soon will you see a change, how do you measure it at home, and when do you need the GP?

Give it weeks, not days. The Cochrane salt trials all ran 4 weeks or longer, the exercise trials at least 2 weeks, and sodium trials under 15 days underestimated the benefit. Judge any change after a month or two of home readings, not after a bad morning.

The HSE home protocol: sit with your back supported and legs uncrossed for at least 5 minutes, take 2 readings 1 minute apart, do that morning and evening, and keep it up for 7 days (HSE). Bring the readings to your GP or nurse, who will use them to work out your average. If you are buying a monitor, the HSE points to STRIDE-BP, which provides a list of recommended and tested devices approved for home use (HSE).

When you need the GP: the HSE says that if your pressure is consistently above 140/90 (or 135/85 at home) but your risk of other problems is low, you will be advised to make some changes to your lifestyle. If it is consistently above 140/90 and your risk of other problems is high, you will be offered medicine. If it is consistently above 160/100, you will be offered medicine to lower it (HSE). Everyone with high blood pressure is advised to make healthy lifestyle changes, and you can take these steps even if you already take blood pressure medicines. None of it is a reason to skip the appointment or stop tablets you have been prescribed.