There’s no doubting the benefits a daily workout routine can have on the human body. But when pushed to the maximum, medical studies suggest that deep burn after pushing the body to the limit might actually be more of a red flag for potential problems, as opposed to a sign of progress.

At least two studies in recent years have found permanent scar tissue and structural changes in the hearts of otherwise healthy men who are avid marathoners or long-time performance athletes, according to the Associated Press.

One study — published in the American Physiological Society’s Journal of Applied Physiology in 2011 — followed a group of male athletes who had performed or currently performed at a national level or ran more than 100 marathons across their lifetime.

The men, varying in age from their 20s to 50s, underwent imaging scans of their hearts, and results showed scarring on heart tissues of the men who performed at that higher level over the course of longer periods of time, resulting in weakened heart muscles.

In December, the European Heart Journal also published research that some endurance athletes very well could develop reversible damage to the right ventricle of the heart following their lengthy events.

Known as Phidippides Cardiomyopathy — named for the Greek messenger who ran from Marathon to Athens to announce victory before collapsing dead — in endurance athletes, the weakening of the heart muscles can lead to permanent microinfarcts where heart tissue dies, said Dr. Bradley McElroy, cardiologist at Western Baptist Hospital.

“There is mounting data that extreme exercise can be very detrimental,” McElroy said, highlighting that endurance athletes are also prone to heart rhythm problems attributed to slow heart rates.

While yet another study showed that running up to 20 miles a week at an easy pace prolonged life, but that running more and at higher intensity produced diminishing health results.

“The amount of exercise that you need to maximize cardio is about ten times less than what a marathon runner gets,” McElroy said. “A small amount of exercise is tremendously better than none, moderate exercise is measurably better than a small amount, but extreme exercise gives you very little incremental benefits over moderate levels.”

However, for all the studies that highlight the potential risk to heart tissue, physical exercise remains one of the leading preventive measures in fighting heart disease and obesity. McElroy said exercising properly and knowing the body’s limitations are keys to starting an exercise regimen that will benefit the body.

“Think of exercise as medication,” he said. “If it’s prescribed correctly, there’s no better medication than exercise for most of the conditions we deal with.

“But for marathon runners, there’s no appreciable benefit in that vigorous exercise as far as cardiovascular exercise.”

For endurance athletes, McElroy suggested participating in no more than one such strenuous event each week. But for the findings of the recent data, fewer people fall under the category of potential over-exercisers.

McElroy: “A very, very small number of Americans exercise to the point of harm, but the vast majority that come up wrong on the exercise issue, come up on the short side of the stick.”

The Associated Press contributed to this article.

Call Will Pinkston, a Paducah Sun staff writer, at 270-575-8676.