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According to the Researchers from the Harvard Department of Stem Cell and Regenerative Biology HSCRB, Massachusetts General Hospital MGH and Harvard Medical School HMS, and the Harvard Stem Cell Institute HSCI, exercise stimulates the heart to make new muscle cells under normal conditions and after a heart attack.
The human heart has a relatively low capacity to regenerate itself. Young adults can renew around 1% of their heart muscle cells every year, and that rate decreases with age. Losing heart cells is linked to heart failure, interventions that increase new heart cell formation can prevent heart failure.
To test the effects of exercise, the researchers gave one group of healthy mice voluntary access to a treadmill. When left to their own devices, the mice ran around five kilometers each day. The other healthy group had no such gym membership, and remained sedentary.
To measure heart regeneration in the mice, the researchers administered a labelled chemical that was incorporated into newly made DNA as cells prepared to divide. By following the labelled DNA in the heart muscle, they could see where new cells were being produced.
They discovered that the exercising mice made over four and a half times the number of new heart muscle cells than the mice without treadmill access. After experiencing a heart attack, mice with treadmill access still ran five kilometers a day, voluntarily. Compared to their sedentary counterparts, the exercising mice showed an increase in the area of heart tissue where new muscle cells were made. Daily exercise leads to regenerating of heart tissue. Maintaining a healthy heart requires balancing the loss of heart muscle cells due to injury or aging with the regeneration of heart muscle cells.
haleplushearty.org