Blood pressure and weight loss: what changes for your heart

Key takeaways - In a meta-analysis of randomised trials, blood pressure fell by about 1 mmHg for every kilo of weight lost, on average. - European guidelines now aim for a systolic blood pressure of 120-129 mmHg in most adults on treatment, if tolerated. UK guidance uses slightly different thresholds. - In the SELECT trial, people with established heart disease and overweight or obesity had 20% fewer major cardiovascular events on a weekly GLP-1-based medicine than on placebo. - Less salt, less alcohol and regular activity lower blood pressure too, and the effects add up. - Never stop or change blood pressure medicine on your own. Doses sometimes need to be reduced as weight falls, and that is a decision for your doctor.

If you have been told your blood pressure is high, or "a bit on the high side", you may also have been told that losing weight would help. That is true, and the effect is larger than many people expect.

This guide explains how weight and blood pressure are linked, how much difference weight loss makes, the targets doctors use, what the SELECT trial showed about heart events, and other practical steps that help.

Why blood pressure matters

Blood pressure is the force of blood against the walls of your arteries. It is written as two numbers: systolic (the pressure when the heart beats) over diastolic (the pressure between beats), measured in millimetres of mercury (mmHg).

High blood pressure rarely causes symptoms, but over years it strains the heart and damages blood vessels. It is one of the main risk factors for heart attack, stroke, heart failure, kidney disease and dementia. Lowering it, by any safe means, reduces those risks.

How weight affects blood pressure

Extra body weight, especially fat around the abdomen, raises blood pressure in several ways. The heart has to pump more blood, the kidneys hold on to more salt and water, the nervous system that controls blood vessels becomes more active, and insulin resistance affects how blood vessels relax. Sleep apnoea, which is more common at higher weights, also raises blood pressure. Our guide to sleep apnoea and weight loss covers that link.

How much difference does weight loss make?

A meta-analysis of 25 randomised trials with nearly 5,000 participants found that, on average, systolic and diastolic blood pressure each fell by about 1 mmHg for every kilo of weight lost. An average loss of around 5 kg lowered blood pressure by about 4.4/3.6 mmHg.

That may sound small, but it adds up, and even a few mmHg lower across a population means fewer strokes and heart attacks. Individual responses vary: some people see a much bigger fall, others less. The benefit also depends on keeping the weight off.

Blood pressure targets

Different guidelines use slightly different numbers. The 2024 ESC guidelines, used across Europe, introduced an "elevated blood pressure" category and a lower treatment target. The NICE hypertension guideline, used in the UK, sets its targets by age.

	ESC 2024 (Europe)	NICE NG136 (UK)
Non-elevated / normal	Below 120/70 mmHg	Below 140/90 mmHg in clinic
Elevated blood pressure	120-139/70-89 mmHg	Not a separate category
Hypertension	140/90 mmHg or above	Clinic 140/90 or above, confirmed with home or 24-hour readings of 135/85 or above
Treatment target, most adults	Systolic 120-129 mmHg if tolerated	Under 80: below 140/90 in clinic (below 135/85 at home)
Treatment target, older or frail adults	As low as reasonably achievable, individualised	80 and over: below 150/90 in clinic (below 145/85 at home)

Your own target depends on your age, other conditions such as diabetes or kidney disease, and how you tolerate treatment. Home readings are usually a little lower than clinic readings, which is why the targets differ.

Measuring at home

Home monitoring gives a better picture than a single clinic reading. Use a validated upper-arm monitor, sit quietly for five minutes first, keep your arm supported at heart level, and take two readings a minute apart, morning and evening, for several days. Share the average with your doctor.

What the SELECT trial showed

Lower blood pressure is one way weight loss may protect the heart, but the more important question is whether it reduces heart attacks and strokes. The SELECT trial was the first large trial to show fewer heart attacks, strokes and cardiovascular deaths with a weight-loss medicine in people without diabetes.

It included 17,604 adults aged 45 or over with established cardiovascular disease (for example a previous heart attack or stroke) and a BMI of 27 or more, but without diabetes. They were randomly assigned to a once-weekly GLP-1-based medicine or a placebo, on top of standard heart care, and followed for an average of about 40 months.

• Major cardiovascular events (cardiovascular death, non-fatal heart attack or non-fatal stroke) occurred in 6.5% of the medicine group and 8.0% of the placebo group, a relative reduction of 20%.
• People stopped treatment because of side effects more often on the medicine (about 17%) than on placebo (about 8%), mainly because of digestive symptoms.

Caveats matter here:

• the results apply to people who already had heart disease, not to everyone with overweight;
• the absolute difference was 1.5 percentage points over around three years, so most people in both groups did not have an event;
• it is not clear how much of the benefit came from weight loss itself and how much from other effects of the medicine;
• the trial was funded by the manufacturer.

Weight-loss medicine is not a replacement for blood pressure, cholesterol or other heart medicines.

Other changes that lower blood pressure

Weight loss works best alongside other steps. Each one adds a little, and together they can make a real difference.

Cut back on salt

Most salt comes from bread, processed meat, cheese, ready meals, sauces and snacks, not the salt shaker. The ESC guidelines recommend limiting sodium to about 2 g a day, roughly 5 g of salt or one level teaspoon. Checking labels and cooking more from fresh ingredients helps most.

Drink less alcohol

Alcohol raises blood pressure, and regular heavier drinking makes it harder to control. It also adds energy and can increase appetite. WHO Europe states that no level of alcohol is safe for health, so less is better. Our guide to alcohol and weight loss has practical ideas.

Move regularly

Regular activity lowers blood pressure, independently of weight loss. The WHO physical activity guidelines recommend 150-300 minutes of moderate activity a week, such as brisk walking or cycling, plus muscle-strengthening exercise on two or more days. If you have heart disease or very high blood pressure, check with your doctor before starting something strenuous.

Eat more potassium-rich foods

Vegetables, fruit, pulses, nuts and dairy contain potassium, which helps balance the effect of salt. If you have kidney disease or take certain medicines, ask your doctor first, because potassium may need to be limited.

Look after other risk factors

High blood pressure often comes with raised blood sugar and cholesterol. Weight loss tends to improve all three. Our article on prediabetes and weight loss explains the blood sugar side. To see roughly how much energy you use each day, the TDEE calculator gives a starting estimate.

Blood pressure medicine and weight loss

If you take blood pressure medicine and start losing weight, your blood pressure may fall. Sometimes it falls enough that a dose needs to be reduced. Feeling dizzy or light-headed when you stand up can be a sign. Keep taking your medicine as prescribed, keep monitoring at home, and let your doctor know if your readings drop or you feel unwell. Never stop a blood pressure medicine on your own.

When medical weight management fits

If clinically appropriate, a doctor may prescribe a weight-loss medicine for people living with obesity or overweight with related conditions such as high blood pressure. It works alongside eating, activity and the rest of your heart care, not instead of it. A doctor will look at your blood pressure, heart history and current medicines before deciding.

How Docalo can help

Docalo is an online medical service focused only on weight loss. Your €49/month membership covers a doctor consultation, a personal plan and follow-up with the medical team. Your plan can take your blood pressure and heart health into account, while diagnosis and management of high blood pressure stay with your usual doctor.

A licensed doctor reviews your health questionnaire and decides whether treatment is appropriate for you. If they prescribe medication, it is paid separately at the pharmacy. When you are ready, you can start your consultation.