Exercise during pregnancy may help mitigate negative effects of parental obesity in children

New research in mice suggests that exercising during pregnancy may help prevent children-;especially boys-;from developing health problems related to their parents' obesity. The study is published ahead of print in the Journal of Applied Physiology. It was chosen as an APSselect article for February.

Obesity during pregnancy increases the risk that the children of obese parents will have metabolic disorders, such as diabetes, later in life. Exercising during pregnancy has been shown to improve pregnancy outcomes, leading to a healthy birth. However, less is known about whether physical activity during gestation can improve metabolic health and reduce the risk of negative changes in the next generation's gene expression due to its parents' health or lifestyle.

Researchers performed two parallel arms of a study in which they examined the effects of maternal and paternal obesity on the offspring's metabolic health and gene expression in skeletal muscle. Adult mice were fed either a high-fat diet to induce obesity or normal rodent chow for six weeks before mating. Some of the mothers (dams) had access to an exercise wheel during pregnancy and others did not. Offspring that resulted fell into one of the following categories:

• from obese mothers that exercised during pregnancy and lean fathers,
• from obese mothers that did not exercise during pregnancy and lean fathers,
• from obese fathers and lean mothers that exercised during pregnancy, and
• from obese fathers and lean mothers that did not exercise during pregnancy.

Trial groups were compared with a control group of offspring in which both parents were lean and followed a normal rodent diet. The research group analyzed gene modification, gene expression, blood sugar (glucose) clearance and insulin levels of all young mice.

Both male and female offspring of obese dams benefitted from their mothers' exercise with improved insulin and glucose clearance, but the males generally showed more significant improvement than their female counterparts. For example, male offspring of obese parents displayed impaired glucose clearance, but the animals from mothers that exercised during pregnancy showed normal glucose clearance on a timed glucose tolerance test. The changes in female offspring were consistent, but much less dramatic.

Maternal exercise also offset the altered gene expression that occurred in mice of both sexes from obese dams. Several of the genes affected include those that play a role in immune regulation and fat metabolism.

The results also suggest that "maternal [obesity] is more potent than paternal [obesity] in predisposing the offspring, particularly the male offspring, to adulthood metabolic impairment, and maternal exercise during gestation only had positive effects on both male and female offspring," the authors wrote.