It seems some people have a natural affinity for exercising, while others have to force themselves to hit the gym. A new study in mice suggests that our experience in the womb affects whether we are physically active or not; pregnant mice that exercised had offspring that were more physically active throughout their lives.

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A mouse study reveals that exercise during pregnancy results in offspring that are more prone to engage in physical activity throughout their lives.

The study, led by Prof. Robert A Waterland of Baylor and Texas Children’s Hospital, is published in The FASEB Journal.

In the wake of the current obesity epidemic taking place in the US, finding ways of encouraging people to be physically active has important public health implications.

Currently in the US, more than one third of adults are obese. For children and adolescents between 2-19 years of age, 17% are obese, putting them at risk of heart disease, stroke, type 2 diabetes and certain types of cancer.

Prof. Waterland says previous observational studies have found that pregnant women who are physically active have children who are more likely to be physically active. These results, however, could be due to the mothers’ influence on the children post-birth.

Furthermore, mothers could pass on a genetic predisposition to be physically active to their children.

“Our study in a mouse model is important because we can take all those effects out of the equation,” says Prof. Waterland.

To conduct their study, the researchers used female mice that naturally enjoyed running and then divided them into two separate groups. While one group was allowed access to running wheels both before and during pregnancy, the other group was not allowed access.

The researchers observed that the mice with running wheels ran an average of 10 km per night. Although they ran less as their pregnancies progressed, they ran or walked around 3 km per night in the third trimester.

Results showed that the mice born to mothers that were physically active during pregnancy were 50% more physically active, compared with the offspring of mothers that did not exercise.

And this physical activity continued in later adulthood, even enhancing the ability of the mice to lose fat during a 3-week exercise program.

“I think our results offer a very positive message,” says Prof. Waterland. “If expectant mothers know that exercise is not only good for them but also may offer lifelong benefits for their babies, I think they will be more motivated to get moving.” He adds:

Although most people assume that an individual’s tendency to be physically active is determined by genetics, our results clearly show that the environment can play an important role during fetal development.”

The American Congress of Obstetricians and Gynecologists (ACOG) recommend that pregnant women who are free of complications exercise at least 30 minutes on most days to prevent gestational diabetes, reduce backaches, increase energy, improve mood and promote better sleep.

There are certain sports that are particularly safe and beneficial during pregnancy, including: walking, swimming, cycling, aerobics and even running.

Prof. Waterland notes that although their study was conducted in mice, “several human studies have reported results consistent with ours.”

He and his colleagues say that if their results can be confirmed in humans, it could be an effective way of combatting the obesity and physical inactivity epidemic we are currently facing.

Concluding their study, the researchers write:

Our finding show for the first time that maternal physical activity during pregnancy affects the offspring’s lifelong propensity for physical activity and may have important implications for combating the worldwide epidemic of physical inactivity and obesity.”

Medical News Today recently reported on a study that suggested stress before pregnancy is linked to birth weight.