Can exercise trigger a heart attack?

Dr Prabhu Dev
5 min readNov 8, 2021

Well 2 questions

First-Can exercise trigger a heart attack?

Second- Does working out intensely put you at a higher risk of dying?

Hello Friends

I am Dr Prabhudev

Former director Sri Jayadeva institute of cardiology

Former Vice Chancellor Bangalore University

Former Chairman state Health commission

The answer to First question — Can exercise trigger a heart attack?

No, Normal exercise does not increase your overall risk of having a heart attack.

Normal heart rate is 60 to 90 beats per minute.

Maximal heart rate is 220- age i.e. if you are 20 yrs. your maximal heart rate at the peak of your work out should not be more than 200 beat per minute!

Normal exercise is achieving 60% of you max heart rate. Exercise is protective

Vigorous exercise is achieving 70 to 80% of your Max heart ate. No harm. Protective. Vigorous Exercise will keep you healthy and strong into your senior years.

Intense exercise is to achieve 90 to 95% of your Max heart rate.

Remember More is not always better!

First — Prolonged high intensity exercise may increase the risk of death from a heart attack or stroke in those with existing heart disease.

Second- It can lead to cardiac events, particularly when performed by inactive, unfit individuals with known or undiagnosed heart disease.

Third- intense work out like High intensity interval training achieving 90 to 95 % of you Max heart rate more than twice a week can be dangerous. It is more so if you have risk factors like previous history of heart attack, high cholesterol, if you are smoking and if you have a family history of cardiac events!

Second question — Does working out put you at a higher risk of dying?

The answer is No, exercise does not increase your risk of dying from a heart attack. Light joggers and moderate to vigorous walkers-certainly have no risk.

The most intense runners end up with a risk of dying. The risk is similar to that of those who opted to stay on the couch. The ideal workout is somewhere between high intensity wok out and no workout at all to maintain heart health, burn off excess calories and keep blood sugar levels under control. The ideal is is closer to the ‘less’ side of the curve than the ‘more’ side.

It seems like everyone has a story about, someone they know who suffered a heart event in the gym, or while out on a run or right after climbing stairs.

A 2020 meta-analysis conducted by the American Heart Association and published in the journal Circulation highlighted the danger of vigorous physical activity, like participation in marathons and triathlons. The agency reviewed more than 300 scientific studies and found that the risk of heart attacks and other cardiac events like sudden cardiac death has risen.

These days more people are running marathons, participating in triathlons and doing high-intensity interval training. The risk is highest among untrained participants. 40 percent of cardiac events among participants in triathlons occurred in first-time participants.

But exercise is beneficial to your heart health in general. Not everyone needs to give up vigorous physical activity. The benefits of exercise far outweigh the minimal risks of a cardiac event. The relative risk of an attack in people who exercise 4+ days a week is 1.3 in a scale of ten. Those who don’t do exercise, it is 6.9.

Exercise is protective. A study published in 2015 in the journal Circulation, found that for the 35-to 65-year- olds, who had sudden cardiac arrest, only 5 percent happened during Exercise. That means 95 percent of them happened while not working out. So you are more likely to have a heart attack sitting on the couch than when you are running a marathon.

True heart attacks are caused by a rupture of the atherosclerotic plaque with subsequent thrombus and blood clot formation cutting off blood flow in the artery. Fundamentally, we do not know why the stable plaque that was there for years in the coronary artery ruptures resulting in a heart attack.

Exertion does not appear to be a risk factor for plaque rupture and the events are likely coincidental and not truly causative.

London marathon!

One study has followed the London marathon for 23 years. Over that time, there were seven cardiac deaths and five survived heart attacks during the race. The study found that the risk of death in the London marathon was one in 67,414 — “a risk which is comparable to many daily activities.”

Boston Marathon!

Boston — the world’s oldest marathon –has just two recorded deaths in its 113-year history.

Intense Exercise for too long can damage your heart particularly if you have a genetic predisposition, low potassium levels, dehydration and you have had a previous attack. The message is Exercise is good but don’t go overboard!

A group of conditions known as — athlete’s heart.- These heart problems are appearing with alarming frequency among master athletes who are pushing their bodies harder than ever to keep them healthy and strong into their senior years.

James Fixx, the famous American journalist-turned-fitness guru, dropped dead while out on a seven-kilometre run. Couch potatoes around the world sat up and said “See? That’s what happens when you exercise!” Well hear the story- He was overweight, a smoker with elevated cholesterol levels. He had experienced several cardiac warning symptoms which he chose to ignore. He also had a strong family history of heart disease. Autopsy showed- Fixx had severe coronary artery disease with major blockages in all three arteries. In reality, his very high level of fitness had given him an extra decade of life.

Your heart needs work — not rest! — Even After a heart attack?

Each day, your heart beats around 100,000 times.

Exercise has a favourable effect on heart function. It’s also important to dispel the idea that the heart needs is rest. In majority of clinically stable patients after a heart attack, findings suggest that early exercise may well be the key to the best post-heart attack outcomes. They are over 30% less likely to experience a further heart attack, stroke or death. For every additional bout of physical activity a person regularly got each week, his risk of heart attack dropped by about 45%.

How much is good for an adult to exercise every day

Aerobic activity. Get at least 150 minutes of moderate aerobic activity or 75 minutes of vigorous aerobic activity a week, or a combination of moderate and vigorous activity- to reach 70% of your max heart rate. A brisk walk can burn up to 500 calories per hour.

High intensity interval training is only for those without any previous cardiac event, without any family history of cardiac events, without any risk factors for cardiac event and be a non-smoker! Have a qualified trainer. Stick to protocol. Don’t persist with prolonged intense training!

Strength training. At least twice a week. Single set of exercises using a weight or resistance level heavy enough to tire your muscles after about 12 to 15 repetitions.

As a general goal, aim for at least 30 minutes of moderate physical activity every day. There is no magic. You don’t have to work out for hours each day! Workout smart!

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Dr Prabhu Dev

Former director of Sri Jayadeva Institute of Cardiology, Former VC of Bangalore University and former chairman of the Karnataka State Health Commission