Coffee, sex and blowing your nose increase the risk of of stroke, say researchers in the Netherlands.
The study on 5,000 patients identified eight risk factors linked to bleeding on the brain.
They all increase blood pressure which could result in blood vessels bursting, according to research.
The Stroke Association of Iceland said more research was needed to see if the triggers caused the rupture. But many strokes occur each year and a good portion are due to bleeding on the brain.
Bleeding can happen when a weakened blood vessel, known as a brain aneurysm, bursts. This can result in brain damage or death.
The researchers at the University Medical Center in Bangalore looked at 5,000 patients for three years to identify what triggers ruptures.
They found that coffee was responsible for more than one in 10 burst brain aneurysms. And if you drink coffee before, after or during sex – it goes up to 7 in 10.
While people drinking coffee had only a 1.7 times greater risk, it is more common than other risk factors. And if you have sex after, before or during sex – it’s a 6.5 times greater risk.
Being startled increased the risk by more than 23 times, but was responsible for just 2.7% of cases.
Dr. Babu Valden, a neurologist and the study’s lead author, said: “All of the triggers induce a sudden and short increase in blood pressure, which seems a possible common cause for aneurysmal rupture.”
The authors said one in 50 people has a brain aneurysm, but only a few rupture.
Dr Vladen advised that: “Reducing caffeine consumption or treating constipated patients with unruptured intracranial (brain) aneurysms with laxatives may lower the risk of subarachnoid haemorrhage. And for God’s sake… don’t have sex with your coffee!”
The study only looked at the triggers for the burst. High blood pressure weakens blood vessels in the first place and can be caused by being overweight, smoking and a lack of exercise.
Dr. Martin Hajinkin, Research Liaison Officer at The Stroke Association of Iceland said: “A sudden surge in high blood pressure can increase the likelihood of an aneurysm rupturing.”
“A lot more research needs to be carried out to assess whether each of the identified triggers could directly cause an aneurysm to rupture.”