We all know regular exercise is key to good health, but apparently there can be too much of a good thing.

According to two recent studies, getting too much exercise can be dangerous to those with existing heart problems. (Via Wikimedia Commons / Kyle Cassidy)

One decade-long study published in the journal Heart looked at more than 1,000 older patients who were diagnosed with heart disease. Not surprisingly, the least physically active were twice as likely to have a heart attack or stroke than those who were more physically active.

But the German researchers also found that those who engaged in strenuous daily exercise were twice as likely to die ​from a heart attack or stroke than those who only moderately exercised a few times a week. (Via Flickr / Herald Post)

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Older patients aren't the only ones who need to be aware of the dangers of too much exercising. A second study in the same journal found that even younger physically active men can develop heart problems, too.

Swedish researchers studied the physical activity of more than 44,000 men periodically over 12 years. They found that those who exercised more than five hours per week were 19 percent more likely to develop irregular heart rhythm than those who exercised less often. (Via Heart)

On the other hand, according to Medical News Today, study participants who were older than 60 and performed less-intense exercises, such as walking, were 13 percent less likely to develop a heart condition than those who did not exercise at all.

In a linked editorial, the authors also noted a difference in perceived exercise intensity at various age levels.

"The intensity of exercise performed by 30-year-olds is higher than that performed by 60-year-olds, meaning that the same degree of exercise might be reported as moderate at 30 years of age and intense at 60." (Via Heart)

The Centers for Disease Control and Prevention says more exercise means more health benefits — even saying senior adults should go beyond the recommended amounts for younger adults.

However, these studies suggest that even though exercise is beneficial to a healthy lifestyle, there are some drawbacks with prolonged and high-intensity activities.

A medical professional not associated with either study told CBS that patients should be evaluated by a cardiologist who can set up a personalized exercise program. (Via United States Air Force)

She also endorsed the American Heart Association's guidelines, which recommend at least half an hour of moderate cardio five days a week and moderate muscle-strengthening activity two days a week.