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Gentle exercise may delay the development of decompensated heart failure (HF), results from an animal study suggest.
The research showed that rats experienced delays in the onset of HF and lived significantly longer if they took low-intensity exercise, described by lead investigator Russell Moore (University of Colorado at Boulder) as the equivalent of a "brisk but comfortable walk."
"The hope is, of course, that our findings are applicable to forms of human HF, but at this stage of the game we would not be so bold as to assert that this would definitely be the case," he told Medwire News.
Moore and team found that 6 months of low-intensity treadmill training markedly delayed the onset of decompensated HF in rats genetically engineered to develop the condition.
All nine animals trained from 16 months of age survived for the next 8 months. Of 10 age-matched sedentary control animals, one died of HF and eight others had terminal overt decompensated HF at 19.5 months of age.
Exercise delayed the shift from α to β myosin heavy chain isoforms seen in sedentary animals that developed HF, the team reports in the American Journal of Physiology – Heart and Circulatory Physiology. It was also linked to an approximate 6% increase in cardiomyocyte length, width, and area and prevented the increase in length-to-width ratio seen in sedentary HF animals.
Emphasizing the importance of low-intensity exercise at tolerable intensity, the researchers found that several rats died early on after their exercise intensity was increased from 10 to 17.5 meters per minute. When this speed was reduced to 14 meters per minute for the duration of the study, no further rat deaths occurred.
Moore said that, although the results seemed "promising," more work still needs to be done.
"It appears that the exercise intervention arrests or retards the maladaptive growth of the heart that occurs during the development of HF. The key question is how, at the cellular and molecular levels, this occurs," he said.
"Some of our collaborators are actively pursuing answers to this important question."
