Exercise takes 10% off the age of old mice muscles
Studies in recent years have continued to illuminate the beneficial ways exercise can influence the aging process, helping tackle vision loss, heart damage and promoting muscle repair, to list a few examples. New research has added to this pool of knowledge through experiments in old mice, which after undergoing an increasingly demanding fitness regime exhibited characteristics of mice eight weeks younger, compared to a control group of sedentary rodents.
The research centers on a biological process known as DNA methylation, in which clusters of atoms called methyl groups interact with the DNA molecule and alter the expression of our genes. This process is impacted by a range of environmental factors such as diet and stress over our lifetimes, and is therefore considered an epigenetic mechanism associated with aging. DNA methylation tends to increase as we grow older.
“DNA methylation changes in a lifespan tend to happen in a somewhat systematic fashion,” explained study author Kevin Murach from the University of Arkansas. “To the point you can look at someone’s DNA from a given tissue sample and with a fair degree of accuracy predict their chronological age.”
The study involved mice close to the end of the lives at 22 months old, who were subjected to a progressive exercise regime involving a weighted running wheel over the course of two months. This program is likened to a human solider carrying a heavy backpack over many miles, and was designed to ensure the mice built muscle throughout.
Studying the mice at the conclusion of the program showed that the late-life exercise had mitigated epigenetic aging in their skeletal muscle. So much so, the epigenetic age of the tissue was found to be around eight weeks younger than a sedentary group of mice of the same age. While the results are promising and reinforce the idea that exercise is good for health, further work is needed to tease out the connection between methylation and muscle function.
The scientists plan to conduct further studies exploring this connection, and investigate whether altered methylation, through exercise or otherwise, can bring about changes in muscle function and health.
“If so, what are the consequences of this?” said Murach. “Do changes on these very specific methylation sites have an actual phenotype that emerges from that? Is it what's causing aging or is it just associated with it? Is it just something that happens in concert with a variety of other things that are happening during the aging process? So that's what we don't know.”
The research was published in the journal Aging Cell.
Source: University of Arkansas