Exercising has many benefits, but too much can actually harm health
Too much exercise like running marathons could damage the heart in men, research has suggested.
A study of those aged 40 and over who had taken part in at least 10 endurance events found that their major arteries were far stiffer than would be expected for their age group.
Overall, men who regularly took part in events such as marathons, ironman triathlons and cycling events were found to have a vascular age a decade older than their chronological age.
This could put them at greater risk of heart attacks and strokes, experts warned.
But the study of more than 300 regular athletes found women who took part in endurance events saw a health boost. By one measure, their vascular age was six years younger than their true age.
Scientists said that the study, funded by the British Heart Foundation and Cardiac Risk in the Young, could not explain why endurance events appeared to have such different impacts on men and women.
Other studies have shown that making hearts work harder to pump blood around the body can cause changes to the heart.
Researchers said that in general, exercise cuts the risk of heart and circulatory problems, saying the benefits of moderate, regular activity for heart health are well proven.
They said more research was needed to see why endurance events might have a negative impact on male arteries.
The research, which has not yet been peer-reviewed, was presented at the British Cardiovascular Society (BCS) conference in Manchester.
For the study, researchers from Barts Heart Centre at St Bartholomew’s Hospital, St George’s Hospital and University College London (UCL) studied more than 300 “masters” athletes, with an equal number of men and women.
These were people aged over 40 who had taken part in more than 10 endurance events and had exercised regularly for at least 10 years.
Distance runners made up the largest group, with cyclists, swimmers and rowers also among those studied.
Heart MRI scans were used to study the stiffness of the athlete’s aorta, the largest artery in the human body, which carries oxygen-rich blood away from the heart to the rest of the body and the brain.
Researchers found that the aortas of the men were stiffer and, on average, 9.6 years older than their chronological age. Female athletes had a vascular age that was around the same as their actual age, researchers found.
When scientists examined the descending aorta, which runs through the chest, even more significant differences were found between men and women.
For male athletes, the vascular age was found to be 15 years older than the average male chronological age. And by this measure, female athletes had a vascular age six years lower than the average for their age.
Prof James Leiper, the associate medical director at the British Heart Foundation, said further research was needed, but added: “For athletes who train in endurance exercise, their hearts must work harder to pump blood around the body – and research has shown that in some cases, this can cause changes to the heart.
“It is important to note that exercise is proven to reduce the risk of heart and circulatory diseases, helping to control weight and lower both blood pressure and cholesterol.”
‘Women’s hearts feel younger after a long run’
Dr Rebecca Hughes, a clinical research fellow at UCL and the Barts Heart Centre, who led the study, said: “Our research showed that in masters athletes, the aorta is generally stiffer in men and their vascular age is therefore older.
“But for women, we saw a surprisingly opposite finding, as some areas of their aorta were several years younger than their chronological age. In non-athletes, aortic stiffening is associated with heart and circulatory diseases.
“How this finding applies to potential risk in athletes is not yet fully understood, so more work will be needed to help identify who could be more at risk.”
While anyone can be affected by heart and circulatory disease, more men in the general population are likely to be affected than women.
About four million men and 3.6 million women are currently living with heart and circulatory diseases in the UK.