Lowering blood pressure through breathing: what's behind it

Of all the measures mentioned in connection with blood pressure, breathing is the only one you can try immediately and without any aids. That makes it attractive – and prone to exaggeration.

This article describes what actually happens physiologically and explicitly names the limits.

The mechanism

The heart and blood vessels are controlled by the autonomic nervous system. It has two opposing branches: the sympathetic nervous system, which raises pulse and blood pressure, and the parasympathetic nervous system, whose most important representative is the vagus nerve and which lowers both.

Breathing is the only autonomic function that can also be controlled voluntarily – and it intervenes in this system. When you breathe in, the pulse rises slightly; when you breathe out, it falls. This phenomenon is called respiratory sinus arrhythmia and is a normal sign of a well-regulated circulation.

If you slow your breathing to about six breaths per minute and make the out-breath longer than the in-breath, the balance shifts towards the parasympathetic system. In addition, the baroreceptors – pressure sensors in the carotid artery and aortic arch – become more sensitive. The result is a measurable calming of circulatory regulation.

What follows from this – and what does not

Two effects need to be distinguished.

In the short term, slow breathing lowers blood pressure during and immediately after the exercise. This is easy to understand and is the reason why the five minutes of rest before each measurement are part of the protocol. If you measure straight after climbing the stairs, you are measuring the stairs too – see Measuring blood pressure correctly.

In the long term, meaning a lasting reduction in resting blood pressure over weeks, the evidence is inconsistent. There are studies on device-guided breathing training with positive results and investigations that found no relevant effect. Professional societies therefore do not list breathing training as a stand-alone blood-pressure-lowering measure on a par with weight loss, salt reduction, exercise or avoiding alcohol.

That is why we deliberately give no figures here. Anyone who promises you a specific reduction in mmHg from breathing exercises is going beyond what the evidence supports.

For comparison: for tea there is a robust figure from 25 controlled studies – and it is very small. Exactly how small is explained in Tea and blood pressure: what the research really shows.

Where breathing still makes sense

The benefit lies less in the number than in how you deal with the topic:

• Before measuring. Sitting quietly for five minutes and breathing slowly makes your readings comparable. This is not massaging the figures but a prerequisite for correct measurement.
• Against measurement anxiety. Many people become tense when the cuff is put on, the reading rises, and the tension grows. Slow breathing breaks this spiral. Why individual readings fluctuate anyway is explained in Why your blood pressure is different every time you measure.
• As part of stress management. Chronic stress is a recognised factor influencing blood pressure. Breathing exercises are an easy way in – comparable to progressive muscle relaxation or mindfulness exercises.
• Because they cost nothing and harm no one. That is a legitimate argument, as long as they do not replace anything.

One exercise, step by step

Sit upright, feet flat on the floor, shoulders relaxed. Place one hand on your belly.

1. Breathe in through your nose for four seconds – so that your belly rises, not your chest.
2. Breathe out through slightly open lips for six seconds, without forcing.
3. Keep breathing without a pause. This gives six breaths per minute.
4. For five minutes, once or twice a day.

If you feel dizzy, you are breathing too deeply or too fast. The exercise should be calm, not strenuous. Reduce the depth, not the pace.

What breathing is not

A breathing exercise is not a substitute for blood pressure medication. Do not stop prescribed medication or reduce the dose on your own – not even if your readings look good. Good readings under treatment mean the treatment is working.

Nor is it an emergency tool. With a severely raised reading accompanied by symptoms, the medical route applies, not the exercise.

And it is no reason to skip the measures with proven effect: regular exercise, salt reduction, achieving a healthy weight, moderate alcohol consumption, stopping smoking and sufficient sleep. If your sleep is disturbed, take a look at Sleep apnoea and high blood pressure.

When you should seek medical advice

• If your weekly average at home is at or above 135/85 mmHg
• Before using breathing training as part of a blood pressure strategy – so that expectations remain realistic
• If you repeatedly feel dizzy during the exercises
• If you are considering reducing medication – always only after consulting your doctor

In case of sudden severe headache, chest pain, speech or vision problems or one-sided paralysis: call the emergency services on 112 immediately (the European emergency number).