Over a lifetime exercise training has been shown to promote numerous health benefits and it can prevent diseases such as type 2 diabetes, heart disease, and cancer, but the mechanisms behind these actions are not fully understood.
“Although short bouts of exercise have been shown to influence the gene activity in our muscles, it is the dedication to habitual exercise over a lifetime that is associated with long-term health benefits,” says lead author Mark Chapman, assistant professor at the Department of Integrated Engineering, University of San Diego and researcher at the Department of Physiology and Pharmacology, Karolinska Institutet. “Thus, understanding how our muscles are changing over many years of training is critical to determining a link between exercise and health.“
This study involved individuals that had performed intensive exercise training for at least the past 15 years which was either long term endurance training, strength training, and age matched untrained healthy controls. RNA sequencing was performed to measure the activity of over 20,000 genes from skeletal muscle biopsies that were collected from all 40 participants.
Long term endurance training was found to have significantly changed the activity of over 1,000 genes in both genders compared to the controls, with many of the altered genes being related to an increased activity in numerous metabolic pathways related to the prevention of metabolic diseases. Only 25 genes were found to be altered with long term weightlifting, suggesting that strength training doesn’t result in accumulated changes in gene activity; it was noted that gene activity may still be affected with weightlifting, but the changes in muscle gene activity may be related to proteins rather than RNA.
Over 450 genes were found to be expressed differently in the muscles of untrained male participants as compared to their female counterparts; such differences are known to exist but this study demonstrates that sex differences decreased about 70% with long term endurance training.
Data was cross referenced with studies examining muscle gene expression before and after a month long training period in participants with type 2 diabetes; findings showed that following short exercise programs those with impaired metabolism shifted their gene activity to become more similar to that of those in the long term endurance groups compared to before they began training.
“This suggests that even short training programs of 6–12 months are enough to positively influence the health of people suffering from metabolic disorders,” says last author Carl Johan Sundberg, professor at the Department of Physiology and Pharmacology, Karolinska Institutet. “The study identifies important ‘exercise-responsive’ genes that may play a role in metabolic diseases.”
