Researchers tested how exercise impacted the hearts of two groups of mice. The first group had access to a running wheel that they could use at will, while the second group did not have access to a wheel and was used as a sedentary control group. The mice with access to wheels ran about 5.5 km per day. The team monitored the two groups of mice for a period of 8 weeks and saw major differences in their hearts. They found that those which exercised regularly had an increased mass of their hearts than others. The signs indicate increased heart hypertrophy (growth & development). The exercising mice were regenerating their heart cells. The effect was quite large, with the exercising mice producing about 4.5 times the number of new heart cells as the control group.

Heart cells in humans are relatively hard to regenerate and losing heart cells has been linked to heart failure. Regenerating new cells may also help patients recover from heart attacks — heart attacks damage heart cells, and regenerating cells is an important recovery method. Interestingly, exercise has also been linked to the growth of new brain cells and increased brain connectivity. The human body has an amazing capacity for regeneration, and exercise may improve and accelerate the body’s regenerative qualities.

Sources: Harvard Health, Nature Communications, Medical News Today, Science Daily, Physiology International, Scientific American