It’s safe even if it’s vigorous

5 minute read

‘Game changing’ new evidence overturns decades of advice about the risk of exercise in people with hypertrophic cardiomyopathy.

Vigorous exercise is safe in people with hypertrophic cardiomyopathy and doesn’t increase the risk of having a cardiac event compared to people who do only light or no exercise, international research suggests.  

Sydney cardiologist Professor Chris Semsarian and colleagues found that people with hypertrophic cardiomyopathy who did vigorous exercise compared with those who did low to moderate intensity exercise did not have a higher risk of death, cardiac arrest, appropriate ICD shocks or arrhythmic syncope.

The 1660 participants, aged from eight to 60 (average 39 years), all had hypertrophic cardiomyopathy, a genetic condition affecting around one in 500 people.

The study showed that among the patients who had done vigorous physical activity over the previous year, 4.6% had died, had resuscitated sudden cardiac arrest, had appropriate ICD therapy or arrhythmic syncope. However, this percentage was almost identical (4.7%) to that among the non-vigorous group.

The researchers also found that people who participated in high-intensity competitive sport weren’t at increased risk of death within the three-year study period.

“Among the subgroup of 42 younger, highly competitive athletes with overt hypertrophic cardiomyopathy, there was one adverse event (nonfatal), which did not occur during competitive exercise. In total, these findings do not support universal restriction of vigorous intensity exercise in patients with hypertrophic cardiomyopathy,” they wrote in JAMA Cardiology.

Professor Semsarian said this was the largest study to address the question of whether vigorous exercise increased the risk of sudden death or arrhythmia problems.

“There’s no difference whether you did a lot of heavy exercise, or just went for a walk every day or didn’t do any exercise. There’s no difference in outcomes in terms of sudden death or rhythm problems,” said Professor Semsarian, who runs the hypertrophic cardiomyopathy clinical program at Sydney’s Royal Prince Alfred Hospital.

“That’s very clinically relevant because what it means is we should be allowing our patients to do more regular exercise, because the benefits of exercise far outweigh any of the minor risks in these conditions.

Professor Semsarian said cases of high-profile athletes with hypertrophic cardiomyopathy collapsing on the field had led to a “taboo” around allowing patients with the condition to play competitive sport.

“We used to tell patients 20 years ago that you can’t do any exercise at all.

“What’s changed over the last several years is that more and more we’re realising that the denominator is quite large.

“So yes, there are deaths, but as a proportion of people who play that don’t have any sudden death experiences it’s a very, very small percentage of the hypertrophic cardiomyopathy population.”

Professor Semsarian said the results gave clinicians more confidence to let patients exercise without worrying about a sudden death event.

“I hate using terms like ‘game changer’, but it is a bit of a game changer because this tells us that it’s safe to allow most of our patients with this condition to exercise, and exercise is great for you.”

Lead author Dr Rachel Lampert said when they looked at sub-groups, they found that the cardiac arrests and deaths had all occurred in men, but the overall event rate including ICD shocks was equal between genders.

The professor of medicine at Yale School of Medicine said they also found that varsity athletes with hypertrophic cardiomyopathy did not have a higher rate of events compared to kids of the same age who did moderate or no exercise.

“In fact, they actually had a lower event rate,” Dr Lampert said in an interview with JAMA Cardiology.

“The group wasn’t large enough for a meaningful statistical comparison. But I do think it’s reassuring that the event rate in this group was numerically lower than in the other groups.”

Dr Lampert said many participants reported that their physicians told them to restrict their exercise.

“And many of them were not following those restrictions. Understanding how that restriction has also impacted quality of life will really be important as well.”

Study co-author and paediatric cardiologist at Minnesota’s Mayo Clinic, Dr Michael Ackerman, said: “This is an incredibly hopeful and hope-filled message.”

Dr Ackerman said the previous advice to avoid strenuous exercise was well-intentioned.

“The law of the land, the law across the globe was, if in doubt, kick them out.”

But the trickle-down effect of that advice was to “essentially sentence individuals with hypertrophic cardiomyopathy to sedentary living”, he told JAMA Cardiology.

“As an unintended consequence we took away from our patients one of the best medications for the body.”

“When we sort of liberate people to live, I think the message that we see is that patients who exercise the most weren’t at any greater risk than those who exercise the least.

“It’s probably time that we restore one of the most beneficial medicines that we have with encouraging our patients to be active, to exercise and even the ability to exercise potentially at the highest levels of competitive sports.

JAMA Cardiology 2023, online 17 May

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