Cardiologists say that for optimum health we should limit vigorous exercise to between 30 and 50 minutes per day.

The researchers, from Saint Luke’s Mid America Heart Institute, Kansas City, USA, explained in the journal Heart that running for too long or too fast does not do more good to health than a moderately vigorous session of thirty to fifty minutes.

It is a myth to think that more intensive, longer-lasting exercises, such as marathons can only do you extra good. In fact, the researchers said that evidence indicates that marathon-type activities are more likely to harm heart health.

When the baby boomers came of age, marathon running became extremely popular. Most believed that as aerobic exercise is good for you, then much more of the same must be even better.

Thomas Bassler, a doctor/runner in 1975 stated that those who could run a marathon could be completely protected from death caused by coronary heart disease. However, the authors of this report stress that the opposite is probably true.

They explained that extreme endurance exercises may come with a cardiovascular health price.

According to the researchers, chronic extreme endurance exercise seems to “cause excessive ‘wear-and-tear’ on the heart, inducing adverse structural and electrical remodelling, which offsets some of the CV benefits and longevity improvements conferred by moderate physical activity.”

They stress that long-term extreme endurance exercise might not kill you, but it may eliminate some of the health benefits regular moderate exercise provides.

The authors warn:

“If you really want to do a marathon or full distance triathlon, etc, it may be best to do just one or a few and then proceed to safer and healthier exercise patterns.”

They added that a routine of moderate exercise will almost definitely help you live longer. On the other hand, running too fast, too far and for too many years may “speed one’s progress to towards the finishing line of life.”

Scientists from Manitoba University found that any cardiac abnormalities that develop during a marathon resolve within seven days after the race is completed. They added that the effects are similar for runners over the age of 50.

They published their findings in the Journal of Cardiovascular MRI.

First author, Dvinder Jassal, said that it is safe for runners aged over 50 years to run a marathon. He added “There was no evidence of permanent heart damage from repeated marathon running in individuals over the age of 50.”

The researchers examined volunteers who ran in the 2010 and 2011 Manitoba Full Marathon. They were all healthy. They carried out ultrasounds of the heart (echocardiographies), MRI and CT scans, and blood tests. They found that straight after completing a 26.2 mile marathon, the top runners aged 50+ years had transient elevation in blood markers and temporary weakness and swelling of the right side of the heart. These abnormalities returned to normal within seven days of completing the race.

Researchers from Brigham and Women’s Hospital managed to quantify how many years of life are gained by different levels of physical activity. They managed to list the benefits according to different groups of people with varying BMIs (body mass indexes).

In their study, published in PLOS Medicine, they found that adding small amounts of exercise to a person’s daily routine, such as 75 minutes of vigorous walking per week, was linked to living an extra 1.8 years after the age of 40 years, compared to doing nothing at all.

Senior researcher, I-Min Lee, MD, added that anything above this level provided further improvements in life expectancy. Walking briskly for 450 minutes or more per week was found to provide most people with a 4.5-year longer lifespan. They found that the longer people spent each week being physically active, the greater their longevity – this occurred in all age-groups, including obese, overweight and people of normal weight.

Written by Christian Nordqvist