Does Grandparenting Explain Physical Activity Benefits?

Let’s start with a disclosure of vested interests. It’s entirely possible that we hold strong biases about grandparenting and physical activity, since we engage in both with enthusiasm. Nonetheless, it is also objectively true that the active grandparent hypothesis is receiving considerable attention. A new article in PNAS by Daniel Lieberman and colleagues is prompting this attention. They explain:

“Grandparents enhance their reproductive success not just by imparting knowledge and skills but also by being physically active foragers who gather and hunt for food surpluses that they provide to their children and grandchildren.”

In other words, grandparents who are active hold an evolutionary advantage. They can bring children and grandchildren food to increase the odds they will survive, prosper, and add to the gene pool. This hypothesis lines up nicely with Herman Pontzer’s idea that “life is a game of turning energy into kids.”

Asking Why Exercise Keeps Us Healthy Longer

A body of research suggests that physical activity has a greater benefit for longevity as we age. Being more active in later years of life predicts more years of life and more years of healthy life.

Of course, it’s difficult to tease out causality in this relationship. Is activity in later life the result of having greater longevity, the cause of it, or just a marker for something else that’s going on in the background? Lieberman et al suggest that it works both ways:

“Extended human healthspans and lifespans are both a cause and an effect of habitual physical activity.”

In sum, they are telling us that active grandparenting serves, in an evolutionary sense, to increase the odds that children and grandchildren will survive, prosper, and pass on your genes. Active grandparents have an advantage in evolutionary biology. Thus, we evolved biological pathways to keep our bodies working well while they’re active.

Of course, this is a hypothesis. We buy it, though, perhaps because of our biases to favor both grandparenting and staying active. No doubt, these ideas will spark some fascinating research.

Click here for the article by Lieberman et al, here, here, and here for further perspective.

Teddy and Teddy Sledding, photograph © Richard Kyle

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December  1, 2021