Senior author Dr. Robert Waterland, of Baylor College of Medicine in Houston, Texas, said: ‘Our study in a mouse model is important because we can take all those effects out of the equation. We studied genetically identical mice and carefully controlled the amount of physical activity of the mothers before pregnancy.’ Although the study involved lab rodents he said several human studies have reported results similar to theirs.
To reach this conclusion, the team selected female mice that all enjoyed running and divided them into two groups. One was allowed access to running wheels before and during pregnancy, and the other was not. During early pregnancy, female mice with running wheels ran an average of 6.2 miles a night. They ran less as pregnancy progressed but, even by the beginning of the third trimester, they ran (or walked) about 1.9 miles each night. Researchers found the mice born to mothers that exercised were about 50 per cent more physically active than those whose mothers did not. Importantly, their increased activity persisted into later adulthood and even improved their ability to lose fat during a three-week voluntary exercise program.
As both groups of mice loved running, but only one was able to do so during pregnancy, the results suggest that exercise during pregnancy influences the development of the fetus’ brain, with Dr. Waterland commenting that, “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.”
If a similar effect can be confirmed in people, it could be used to counteract the current worldwide epidemic of physical inactivity and obesity.
According to the World Health Organization, insufficient physical activity is one of the ten leading risk factors for death worldwide.
Many leading expert groups, such as the American College of Obstetricians and Gynecologists, already recommend exercise for pregnant women, suggesting 30 minutes of moderate exercise a day for those without any pregnancy complications.
‘I think our results offer a very positive message,’ said Dr. Waterland. ‘If expectant mothers know 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.’
Previous research has shown exercising in pregnancy also helps babies develop healthy hearts. Scientists believe it programs a baby’s arteries to resist heart problems.
At present, women are advised that the more active and fit they are during pregnancy, the easier it will be to cope with labor and get back into shape after the baby arrives.