“Grandma’s workouts may have made you healthier.” Theof a pair of well-worn women’s running shoes caught my eye immediately. For whatever reason, we are a family of exercisers. My wife has competed in several triathlons and won two of them. With her I have cycled across the United States. It has not surprised us that all three of our children have run at least one marathon. I have always viewed their continued devotion to an active lifestyle and their healthy bodies as a tribute to the benefits of our attempts at parenting by example. We certainly didn’t coach them, lecture them, or run family boot camps on weekends and school vacations.
I had never really given much thought as to whether their grandparents also may have played any role in their affinity for physical activity until I read that article. Apparently, my mother was a gifted athlete as a young woman. I have seen photos of her playing tennis, skiing, and diving and heard stories, but I never saw her do any of these activities except a single perfect swan dive when I must have been 8 or 9 years old.
Similarly, scrapbooks reveal that my mother-in-law had an active sports life in high school. But we never saw any evidence of her athletic activity save a devotion to a gentle backstroke in the cold Maine waters during the summer. My wife and I and our children never saw these grandmothers do anything more sporting or physically taxing than single-handedly preparing a full Thanksgiving dinner. How could their exercise habits have influenced the health of their grandchildren?
A team of researchers at the Joslin Diabetes Center in Boston found that female mice who were given the opportunity to exercise produced offspring that had lower fat mass, higher bone mineral density, and insulin levels usually associated with a lower risk of type 2 diabetes. And, in a bit of a surprise, the next generation of offspring accrued a similar benefit even though its mothers were not exercising. The role of exercise in the fathers was eliminated by experimental design.
So it appears that the first-generation offspring’s gametes and hence the third generation was being exposed in utero to something generated by the grandmothers’ exercise. It does not appear to be a behavior pattern that is passed on. It may have to do with epigenetics. Searching for this unknown factor is ongoing and broad based.
Obviously, similar studies in humans are not on the drawing board. Our reproductive cycle is significantly longer than the 2 years of the mouse. However, looking at their current data, the researchers feel comfortable encouraging a mother to exercise during pregnancy as long as it is compatible with the particulars of her obstetrical course. It would be unkind and without basis in fact to blame your mother’s or your mother-in-law’s sedentary behavior for your child’s poor metabolic health. However, it is reasonable to point out to women considering pregnancy that, in addition to avoiding alcohol and smoking, a good dose of exercise during pregnancy will benefit their children. You can point out that it may even benefit their grandchildren. And of course, once the baby is born and a mother feels comfortable returning to her exercise regime, she should go for it. Remind her also that parenting by example is still the best way to do it.
Dr. Wilkoff practiced primary care pediatrics in Brunswick, Maine, for nearly 40 years. He has authored several books on behavioral pediatrics, including “How to Say No to Your Toddler.” Other than a Littman stethoscope he accepted as a first-year medical student in 1966, Dr. Wilkoff reports having nothing to disclose. Email him at.