New findings show that taking a break from exercise could actually enhance muscle growth when you return, with significant muscle gains seen in mice after a second bout of running.
For those who’ve found themselves faltering from their regular gym routines, a new study offers promising news: taking a break might not be as detrimental to muscle growth as previously thought. Researchers at the University of Illinois Urbana-Champaign discovered that mice which resumed exercise after a hiatus experienced even greater muscle gains than during their initial training period.
The research, led by health and kinesiology professor Diego Hernandez-Saavedra and doctoral candidate Clay Weidenhamer, unveiled that the second stint of running led to a more significant increase in muscle fiber size, despite a decrease in exercise intensity.
“My lab is very interested in understanding whether our body remembers that we’ve exercised before,” Hernandez-Saavedra said in a news release. “Do we have this sort of memory in our body that keeps us healthier or makes us stronger over time?”
Earlier studies have suggested that muscle memory is influenced by muscle satellite cells, which merge with muscle fibers to enhance growth. However, the retention of new nuclei post-exercise has been debated among scientists.
To delve deeper, the team observed the molecular mechanisms of muscle memory by tracking gene expression at different stages. They included a one-week “washout period” where the mice ceased exercising to gauge enduring effects.
Despite the initial adaptations seemingly dissipating, the second bout of exercise still yielded a striking up to 30% increase in muscle mass compared to mice that only exercised once.
The research found that gene analysis showed a significant enhancement of genes linked to mitochondrial function following the second exercise phase, underscoring the importance of mitochondria — the cell’s energy producers — in muscle memory.
“We didn’t see increases in markers associated with mitochondrial function with the first bout of exercise, even after they stopped exercising, but only after the second bout of exercise,” Hernandez-Saavedra added.
Interestingly, whether the mice were fed a control diet or a high-fat diet, the increases in muscle growth were consistent, suggesting that the exercise memory might counterbalance poor dietary habits.
This revelation holds potential implications for combating frailty and metabolic diseases, emphasizing that aerobic exercises like running can effectively contribute to muscle growth and health.
“These insights may help identify strategies to preserve muscle health during aging or counteract the effects of a poor diet, opening the door for new interventions against frailty or metabolic disease,” added Hernandez-Saavedra.
Published in the American Journal of Physiology: Cell Physiology, this study highlights a pivotal turning point in understanding muscle memory and the benefits of exercise, even after a lapse.
The researchers note that future studies will observe these dynamics over more extended periods to further comprehend the benefits of muscle memory in enhancing health outcomes.