Do very active people really have
a higher risk of heart attack – as
recent headlines claimed?

Recent studies have shown that over-exercising can cause arteries to harden and
narrow, which is a major risk factor for heart attacks and strokes. People who exercise
regularly should be aware of this danger and ensure that their workouts do not become
overly intense.
A study by researchers at the University of Leicester has found that people who are
very active have higher coronary artery calcium (CAC) scores than those who are less
active. The CAC score measures the amount of calcium in the walls of the coronary
arteries – arteries that supply blood, and hence oxygen, to the heart muscle.
The presence of calcium in the coronary arteries is a sign that there may also be a
buildup of plaque. This condition is known as atherosclerosis, and an increase of
calcium may lead to heart attack.In the body, plaque builds up from a combination of
factors. Smoking, drinking, being overweight and not getting enough exercise are
common causes. Doctors often use CAC scores to identify people at risk for heart
disease.
Researchers at the University School of Medicine in South Korea and Johns Hopkins
Bloomberg School of Public Health in the US analyzed more than 25,000 healthy adults
from March 2011 to December 2017. During this period, participants had
comprehensive check-ups to monitor any changes in their coronary arteries.
A team of researchers wanted to find out if there was a link between physical activity
and increased coronary artery calcification.
All participants were given a questionnaire that measured how active they were each
week. Nearly half the participants (47%) were categorized as inactive, 38% as
moderately active, and 15% as being extremely active (the equivalent of running 6.5km
every day).
Those who exercised more tended to be older and less likely to smoke than the people
who were not as physically active.
The study began by taking scans of the heart arteries in the three groups at the start.
After one year, those who had exercised moderately or intensely saw an increase in
calcium deposits build up in their arteries.
Benefits of exercise are unquestionable
However, new research has found no link between exercise and cardiovascular “events”
such as heart attack or stroke. The headlines of the study which claim that exercise
“raises heart attack risk” are wrong and dangerous. Indeed, the researchers warn
against this interpretation. They conclude:“We need to exercise more and eat less.”
Exercise has many health benefits, including a lower risk of heart disease and death.
This suggests that exercise may increase CAC scores, but it lowers the risk of
cardiovascular diseases, such as heart attack and stroke.
Cardiac plaques are built up over time, and the more of them you have, the higher your
risk for a heart attack. The calcium contained in coronary arteries can build up due to
exercise, which has been found to be protective against heart attacks. Doctors need to
be careful when interpreting CAC scores of healthy people because they might jump to
conclusions that may not be.