Orthostatic hypotension: dizziness on standing, causes and what helps

When you stand, gravity pulls blood towards the legs and the body has to tighten blood vessels and quicken the heart briefly to keep the brain supplied. In orthostatic hypotension that adjustment is too slow or too weak, so pressure falls and blood flow to the head dips for a short time.

Hospital patient information from United Lincolnshire Hospitals gives a working definition of a drop of at least 20 mmHg in the top (systolic) number or 10 mmHg in the bottom (diastolic) number within 3 minutes of standing. The symptoms are usually brief and settle on lying or sitting back down.

Blood pressure also varies through the day. The NHS notes that it depends on the time of day, activity and mood, and that some people simply have naturally low readings because they are fit and healthy or because it runs in the family.

The NHS lists the symptoms that should prompt a blood pressure check when they keep recurring: lightheadedness or dizziness, feeling sick, blurred vision, general weakness, confusion and fainting. If they appear on standing or suddenly changing position, postural hypotension is a likely explanation.

Fainting, the NHS says, usually comes on suddenly with dizziness, sweating, feeling hot, nausea and changes in vision. Standing up too quickly is one of the listed causes, along with not eating or drinking enough, being too hot, strong emotion or pain, heart problems and alcohol or drugs.

• Dizziness or lightheadedness within seconds of standing.

• Blurred or greying vision, weakness and fatigue.

• Nausea.

• Brief loss of consciousness in some people.

Several everyday factors can lower blood pressure on standing. The table collects those given in the NHS and hospital sources. The first thing a clinician usually reviews is the medication list, since the NHS says changing medicines or altering the dose is a recommended step when a medicine is the cause.

A GP, practice nurse or pharmacist can measure blood pressure, and the NHS says you can also check it at home using a monitor. The NHS recommends asking for a check if symptoms keep happening. For postural hypotension, readings taken lying or sitting and then again after standing show whether the pressure falls, as the hospital definition describes.

The cause matters more than the number. A GP will usually ask about medicines, fluid intake, alcohol, other conditions and episodes of fainting, and may recommend further assessment if there is a possible heart or nervous-system cause. Adults aged 40 to 74 are also advised to have their blood pressure checked at least once every 5 years as part of the NHS Health Check.

The United Lincolnshire leaflet describes a step-by-step approach. From lying or reclining, first move to sitting. Let the feet dangle or rest flat on the floor and pause on the edge of the bed or chair for about 15 to 30 seconds while taking slow, deep breaths. Stand by leaning slightly forward and pushing up with legs and hands together, pause again once upright and hold onto something stable if needed, then start walking slowly and sit back down if dizzy.

The NHS adds practical points: get up slowly from sitting, take care getting out of bed, eat small frequent meals, rest after eating, and increase the amount of water you drink. It advises not sitting or standing for long periods, not changing posture suddenly and not drinking too much alcohol. The hospital leaflet also advises avoiding extremely hot showers and large meals and keeping the floor around you clear and walking aids within reach to lower the chance of a fall.

If you feel faint, the NHS suggests lying down with the legs raised or sitting with the head between the knees, drinking water, crossing the legs while standing, rocking on the toes or clenching the fists.

The NHS says that if a cause is found a GP can recommend treatment, for example changing medicines or the dose, or wearing support stockings to improve circulation and raise blood pressure. It also says that medicine to increase blood pressure is rarely needed.

Because the possible causes range from simple dehydration to heart or nerve conditions, anyone whose symptoms persist or who has repeated falls or faints may be referred to a specialist, for example in cardiology, geriatric medicine or neurology. The aim is to find any treatable reason rather than just manage the symptom.

The NHS says to see a GP if you keep getting symptoms of low blood pressure such as dizziness and fainting, and also if you have fainted. It lists situations where someone should call 999: the person is not breathing, cannot be woken within 1 minute, has not fully recovered or has difficulty with speech or movement, has chest pain or a pounding, fluttering or irregular heartbeat, has seriously hurt themselves, is shaking or jerking, fainted while exercising or fainted while lying down.

The NHS also reminds people that anyone who faints regularly must tell the DVLA because it can affect driving, and that you must not drive if a GP has referred you to a specialist and you are waiting to be assessed. It advises against driving yourself to A&E.