Causes-High blood pressure (hypertension)

In most cases, it's not clear exactly what causes high blood pressure (hypertension). But there are several things that can increase your risk.

Who's at risk of high blood pressure

Factors that can raise your risk of developing high blood pressure include:

Making healthy lifestyle changes can help keep your blood pressure at a normal level.

In about 1 in 20 cases, high blood pressure happens as the result of an underlying health condition or taking a certain medicine.

Health conditions that can cause high blood pressure include:

kidney disease
diabetes
long-term kidney infections
obstructive sleep apnoea – where the walls of the throat relax and narrow during sleep, interrupting normal breathing
glomerulonephritis – damage to the tiny filters inside the kidneys
narrowing of the arteries supplying the kidneys
hormone problems – such as an underactive thyroid, an overactive thyroid, Cushing's syndrome, acromegaly, increased levels of the hormone aldosterone (hyperaldosteronism), and phaeochromocytoma
lupus – a condition in which the immune system attacks parts of the body, such as the skin, joints and organs
scleroderma – a condition that causes thickened skin, and sometimes problems with organs and blood vessels

Medicines that can increase your blood pressure include:

the contraceptive pill
steroids
non-steroidal anti-inflammatory drugs (NSAIDs) – such as ibuprofen and naproxen
some pharmacy cough and cold remedies
some herbal remedies – particularly those containing liquorice
some recreational drugs – such as cocaine and amphetamines
some selective serotonin-noradrenaline reuptake inhibitor (SSNRI) antidepressants – such as venlafaxine

In these cases, your blood pressure may return to normal once you stop taking the medicine or drug.