If you're angry or upset, you may want to calm down before heading out for an intense run or a gym workout.
A large, international study has tied heavy exertion while stressed or angry to a tripled risk of having a heart attack within an hour.
Regular exercise is a healthy antidote to stress and can help prevent heart disease, the biggest problem is that too many people get too little of it. But new research suggests there may be better or worse times to exercise, and that extremes can trigger harm.
"This study is further evidence of the connection between mind and body. When you're angry, that's not the time to go out and chop a stack of wood,'' said Barry Jacobs, a psychologist at the Crozer-Keystone Health System in the US.
He had no role in the study which was led by the Population Health Research Institute at McMaster University in Hamilton, Ontario. Results were published on Monday in the Heart Association journal Circulation.
Earlier studies have looked at anger and exertion as heart attack triggers but most were small or in one country, or included few women or minorities. The new study involved 12,461 people suffering a first heart attack in 52 countries. Their average age was 58 and three-fourths were men.
They answered a survey about whether they were angry or upset, or had heavy exertion, in the hour before their heart attack or during the same time period the previous day. That way researchers could compare risk at different times in the same people and the effect of these potential heart attack triggers.
Being angry or upset doubled the risk of suffering heart attack symptoms within an hour; heavy physical exertion did the same. Having both at the same time more than tripled the risk for a heart attack.
The risk was greatest between 6pm and midnight, and was independent of other factors such as smoking, high blood pressure or obesity.
Big caveats: Patients reported their own stress or anger, and people who just had a heart attack may be more prone to recall or think they suffered one of these triggers than they otherwise might have been. Also, strenuous exertion is whatever the patient perceives it to be, for some people that could be climbing stairs and for others, running a marathon.
The study also is observational, so it cannot prove cause and effect. But it's likely to be the best kind of information available - it's not possible to randomly assign people to be angry and exercise, then see how many have heart attacks.
"This is a large enough sample size that we can put stock in the findings,'' Jacobs said.
"We all need to find ways of modifying our emotional reactions and to avoid extreme anger,'' such as distracting ourselves, walking away from the stressful situation, trying to see it from a different perspective, talking it out and getting support from other people, he said.
