The original study
An extensive study conducted in 2018 looked at nearly 22,000 healthy men who self-reported their levels of physical activity. They were mostly runners, cyclists, swimmers, and rowers and they were divided into three groups based on the overall amount of exercise. The high-exercise group exercised the equivalent of cycling at 25-30 km/h for 4 hours a week. The middle group did 2-4 hours, and the low group less than 2 hours. The authors then looked at their levels of coronary artery calcification (CAC), which is a measure of heart health.
High-exercise group is safe
The study found that the high-exercise group had more coronary artery calcification than the other groups. This would suggest that they are at higher risk of heart disease. But despite the higher CAC levels, the participants were about half as likely to die from cardiovascular disease over the next 10 years.
“The current study shows no increased risk of mortality in high-volume, high-intensity athletes who have coronary artery calcium,” said Dr. Laura DeFina, the lead author of the study. “Certainly, these highly active people should review their cardiovascular disease risk with their primary care doctor or cardiologists, but there is no reason to think they can’t continue exercising at high levels.”
Extreme-exercise group is also fine!
The thing is that 4 hours of cycling a week is not really a “high” volume of exercise for many cycling enthusiasts. As it happens, the authors did a review of the data set in November 2019 and included an extreme-exercise group that did 14 hours of cycling at 25-30 km/h a week. There were over 2,100 people in the “high”-exercise group, but only 66 qualified for this new “extreme”-exercise group. The researchers found that the extreme group did not have increased risk of cardiovascular disease compared to the high group!
There are many factors that matter, not just exercise
This is good news for us cycling enthusiasts, but we all need to remind ourselves that exercise is not the only factor. There are genetics, levels of lifestyle stress, alcohol and drug use, eating habits, how much you exercised earlier in life, and many other variables that contribute to the actual risk of heart problems.
The benefits of exercise outweigh the heart risks
One thing that has been confirmed by this study is that the benefits of exercise outweigh its risks. Both the medium- and high-exercise groups had lower mortality risks compared to the low-exercise group. So, we can all keep riding, knowing that as far as we know, cycling is good for us no matter the quantity.