With 80% of people being physically inactive, exercise is one thing most of us should do more of. Despite this, I’ve heard many people say they don’t exercise because they don’t want to overdo it, or they’ve heard too much may be bad for them.
Over 20 plus years, I think I’ve only told one person to cut back on their exercise. This was to an 80 year old patient. There was no fear of her having a heart attack or anything, she was just feeling fatigued from exercising a couple hours each day. Given that she was exercising so much, I suggested she could cut back.
The notion that too much exercise is bad for you became popular following the death of well-known runner Jim Fixx. He started the running craze and wrote five books on running including The Complete Book of Running. He was at the young age of 52 and out for a run when he died.
At the time, people were taking this to mean exercise, and more specifically, running, can’t be good for you. I would usually role my eyes when I heard this. Sometimes people would retell the story of Philippides, who was the Greek messenger and the first person to run a marathon around 490 BC. He died upon finishing it.
Is there really anything to this?
When we exercise, our heart beats faster and is working harder. This added stress is good for the heart because like any other muscle, when you work out it gets stronger. But there‘s also a greater chance of having a heart attack or sudden cardiac arrest. However, this risk is extremely small; about 1 death in 36.5 million hours of exercise compared to 1 in 59.4 million hours of sitting. To put this into perspective, if you live to 80 years, that’s only 700 000 hours.
Additionally, regular exercise actually lowers this risk even more. As you get into better shape, your body becomes more efficient. It’s the person who doesn’t exercise, and then exerts his/herself, who is in the most danger. And that exertion doesn’t need to be a planned exercise, often it’s something such as snow shovelling or other unplanned activity.
Since dealing with my irregular heartbeat that occurs during exercise, I’ve had a growing personal interest in this topic. I have some rogue cells that like to get my heart racing super-fast; about 230 to 255 beats per minute. At that speed, the heart isn’t really doing much. There isn’t time for it to fill with blood before it pumps again. So when it happens, I feel like a ton of bricks falling on me. Fortunately, it passes almost as quickly as it starts.
I recently had a CT angiography scan. This scan measures the amount of atherosclerosis (blockage in the heart arteries). My test showed I had a 20% blockage in my left anterior descending artery (LAD; the widow maker). While 20% isn’t much, I was expecting zero.
So here I am exercising regularly, and telling others to do the same, and I find out I have two types of heart disease. One of which I know is tied to my exercise.
In the past two years I’ve learned a lot I never expected to. I’ve realized exercise is a possible risk factor for atrial fibrillation (a rapid and irregular heart beat where the heart chambers aren’t working together). Not just any exercise mind you, extensive endurance exercise. And it’s possible that my irregular heart beat I get may be a sign of things to come.
Although the increased chances of getting atrial fibrillation from exercise goes from 0.4% to 0.8%. And this was found in people regularly participating in a 90 km cross-country ski race. I like to think I exercise a lot, but I’m nowhere near that amount (maybe that’s a good thing).
That being said, exercise is also a recommended treatment in people with atrial fibrillation as it reduces symptoms.
It’s possible that excessive, strenuous exercise may also lead to conditions that promote blockages in the heart. However, it appears the blockages in exercisers are of a different sort than blockages found in people who are inactive. The exercisers tend to have blockages that are considered to be more stable and less likely to lead to a heart attack.
And just like atrial fibrillation, even if you have blockages in your heart (like I do), exercise is still one of the most effective treatments around.
Over the long term, continuous strenuous exercise may not be the best bang for your exercise time. It seems there is a reverse J-shaped relationship between exercise and heart disease. The greatest benefits appear with light and moderate amounts of exercise around 2-4 times per week. This level is associated with the lowest chance of getting heart disease and early death. Doing more is still much better than doing nothing, but not as good as more moderate levels of exercise.
The most important aspect appears to be how often you’re doing strenuous exercise (strenuous is a non-scientific term but refers to getting your heart rate up and feeling like it’s hard work). In people who are very active at light or moderate levels, whether through their job or other means (think of a mail carrier who is walking for 40 plus hours per week), more does tend to be better.
For many of us, we’re unlikely to be exercising at the intensity and amounts that can lead to health issues. So feel free to dive into it. If you have any pre-existing condition or haven’t exercised for several years, start out easy and even consider talking to your doctor. He/she might suggest you have an exercise stress test, which will help in guiding your exercise program. You can also find out more information on starting an exercise program here.
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