How exercising now could benefit your future grandchildren

Exercising now is good for you. But could it also be good for your future children and grandchildren?

A provocative new study says it might be. The findings, based on research in mice, suggest that the exercise we do today is imprinted on our cells in ways that can be passed on to later generations.

In the study, exercise in female mice before and during pregnancy influenced the health of their future offspring and offspring, even if those offspring never exercised.

While you might think a mouse study isn’t very relevant to humans, the idea that one generation’s lifestyle shapes the health of the next is “pretty well recognized” scientifically, said Laurie Goodyear, a professor of medicine at Harvard Medical School. and senior researcher at the Joslin Diabetes Center in Boston, who oversaw the new study.

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In animal and human studies, malnourished mothers and fathers who develop diabetes, obesity and other metabolic disorders often pass on a predisposition to those conditions to their offspring, he said. This propensity is independent of education and lifestyle. That is, babies born to parents with metabolic problems tend to develop these same conditions in adulthood, even if, until then, they had been eating well and staying thin.

Scientists call this process developmental programming. They he suspects it depends as much on the environment inside the mother’s womb during pregnancy as on epigenetics, or small changes in how our genes work, based on how we eat and live. These epigenetic changes can be transmitted to the offspring by the mother or the father, affecting the children’s risks of various diseases.

But Goodyear and other researchers have found that exercise also contributes to developmental programming, of a more welcome kind. Studies from his lab and others show that if mother mice run before mating and during pregnancy, their babies are somewhat protected against developing obesity and diabetes as they grow, up to and all if they eat high-calorie food and do not exercise, themselves. .

Fathers who run before mating can also pass on stronger metabolisms to their offspring, whether their mothers exercise or not, and in a 2018 study, running males had pups with healthier brains from from birth than mice sired by sedentary parents.

But the studies had not looked at whether these protections might be long-lasting enough to show up in grandchildren, even if their parents are sedentary.

So for the new study, which was published in June in Molecular Metabolism, Goodyear and his colleagues had young, female mice run on wheels. Some ate normal food, others an unhealthy, high-fat diet. Another group of female mice on the same diets did not run. All females bred to sedentary male animals and runners continued to exercise throughout their subsequent pregnancies. (The mice seem to enjoy running and, even heavily pregnant, hopped on their wheels for a mile or so most days.)

They gave birth duly. None of their youngsters ran, however, to keep their metabolisms relatively neutral, free of epigenetic and other changes otherwise initiated by exercise. The researchers hoped, in this way, to track the effects of their mothers’ exercise through this sedentary generation. For the same reason, they bred only males from this middle generation, eliminating any potential effect of womb conditions on the babies.

The resulting male and female grandchildren also remained sedentary and ate normal food throughout their lives.

But from birth, mice with active grandmothers were thinner than others, and in males, they had denser and healthier bones. Most interestingly, as the animals moved into middle age, those with inactive grandmothers began to develop poor blood sugar control and worsened insulin sensitivity, signaling potential, and incipient diabetes. These conditions are common with age and inactivity in both rodents and people.

But they didn’t show up if grandma was running. Those mice with an active grandmother maintained relatively healthy blood sugar control and insulin sensitivity into old age, despite being inactive themselves. (Their grandmothers’ ordinary diets, high-fat or normal, hadn’t mattered, the researchers also found, only their exercise.)

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“It was remarkable,” said Ana Alves-Wagner, a senior postdoctoral researcher at the Joslin Diabetes Center and Harvard Medical School, who led the new study. “Exercise had improved the metabolic health of several generations.”

It was obviously a mouse study and impossible to replicate in humans, requiring, as it were, decades of time and draconian coercion over people’s activities, diets, and mating choices. Nor did he examine how, at the molecular level, exercise reshaped the animals’ biology so pervasively that the effects reappeared in later generations.

But Goodyear believes that epigenetics is a key player and that the results likely apply to us, he said, since we share many aspects of our metabolisms and physiological responses to exercise with mice.

If so, the findings become both practical and poignant.

“I was very intrigued when I heard about this study,” said Daniel Lieberman, a professor of human evolutionary biology at Harvard University who studies how physical activity shaped our species during evolution. “Our metabolisms appear to be adapted to respond to environmental cues over generations. We still don’t know the mechanisms by which this happens in mice. Regardless, this study reinforces the view that when we exercise, we’re not just doing it for ourselves.” .

The study, of course, is not meant to criticize any mom or dad-to-be who can’t or chooses not to exercise before having children, Goodyear said. But the results give those of us who choose to work one more reason. Today we can walk or walk for the sake, in part, of the grandchildren expected of tomorrow.

Have a fitness question? e-mail [email protected] and we can answer your question in a future column.

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