ABOVE: When obese female mice exercised during pregnancy, their young grew up to be healthier than pups born to sedentary obese moms. 


The paper
R.C. Laker et al., “Exercise during pregnancy mitigates negative effects of parental obesity on metabolic function in adult mouse offspring,” J Appl Physiol, 130:605–16, 2021.

Obesity is a risk factor for numerous diseases, including cancer and type 2 diabetes. This risk extends to future generations, as parental obesity can leave epigenetic marks in egg and sperm cells that affect the metabolic health of offspring formed from those germ cells. “The health status of the parents matters,” says Zhen Yan, a physician scientist at the University of Virginia who studies exercise physiology. 

Yan’s group had previously studied how exercise before and during pregnancy affected the adult offspring of female mice with diet-induced obesity. Maternal exercise improved glucose tolerance in their offspring, and also curbed DNA hypermethylation—an epigenetic change that can reduce expression of particular genes—of the promoter of PGC-1α, a gene expressed in the adult progeny’s skeletal muscle that encodes a key metabolic regulator. 

In a new study, Yan and his colleagues investigated whether exercise started during pregnancy is enough to improve offspring health in mice. The adult male progeny of obese mothers that never exercised had higher insulin and glucose levels in adulthood compared with the male offspring of sedentary non-obese mothers. But when obese mothers exercised, their offspring did not show hypermethylation of PGC-1α and had normal metabolic health. The researchers also found that maternal exercise compensated for the negative effects of obese fathers on offspring health, preventing a pattern of glucose intolerance in their adult pups, though paternal obesity didn’t affect PGC-1α methylation levels, suggesting a different mechanism is involved.

“I think this work is really interesting. . . . Looking at maternal and paternal influence, in general, is important,” says Kristin Stanford, a physiologist at the Ohio State University who wasn’t involved in the work. How maternal exercise during pregnancy counters the effects of parental obesity remains an open question, as well as how the findings might apply to humans.