KUALA LUMPUR, July 26 — A Japanese man almost died of a stroke after masturbating several times a day.

Quoting a medical case study report, the Daily Mail reported that the 51-year-old suffered a stroke last year moments after ejaculating.

UK’s National Health Service (NHS) said the stroke the man suffered could have been triggered by having sex, coughing and even going to the toilet.

The man was instantly struck down with agonising ‘thunderclap’ headaches after he climaxed, and later began vomiting.

Concerned about his sudden symptoms, he went to Nagoya City University Hospital where checks by doctors found he had low blood pressure and was disoriented — two tell-tale signs of a stroke.

A CT scan of his brain revealed he had endured a subarachnoid haemorrhage — a life-threatening type of stroke that was caused by a blood vessel in his brain rupturing.

The man had since been discharged from the hospital after undergoing treatment for two weeks.

While doctors treating the man did not offer an explanation as to why he may have suffered a stroke from masturbating, the NHS said brain bleeding could happen as a result of physical exertion, such as lifting something heavy or having sex.

Dr Daniel Walsh, a consultant cerebrovascular neurosurgeon at King’s College Hospital NHS Foundation Trust, told the portal that the ruptured aneurysm which caused the patient’s stroke is thought to be linked with a sudden increase in blood pressure, that is "something characteristic” in sexual activity.

Sexual activity of various kinds, including masturbation, has been linked to between 3.8 per cent and 14 per cent of all subarachnoid haemorrhage cases, he said.

Taking drugs like Viagra or cocaine during sex can also increase the risk of having this type of stroke, Dr Walsh added.