Now, for the new study, which was published in July in the Journal of Aging and Physical Activity, the researchers set out to see if a different exercise, in this case cycling, might likewise affect the ease of walking. They recruited older riders and walkers and asked them how strenuously they felt they worked out, on a scale of 1 to 3, from easy to tiring. The walkers’ reported intensity hovered at just under 2, while the cyclists’, as a group, neared 3. The researchers also brought in a group of healthy young people as a control.
Everyone then walked on a treadmill at paces ranging up to about 4 miles per hour while the researchers tracked their oxygen consumption. And, as with the runners, the older cyclists walked well, their efficiency matching that of the young people. But the older walkers’ efficiency was as much as 17 percent lower.
In effect, walking for exercise seemed not to have “supplied sufficient physical stimulus” to maintain people’s ability to walk easily as they aged, says Justus Ortega, a professor at Humboldt State University who co-authored both studies. Running and cycling were associated with more efficient walking than regular walking was.
The studies did not delve into how cycling or running might have affected people’s walking efficiency. But Dr. Ortega says he and his colleagues suspect that the more demanding exertions boosted the health and function of mitochondria inside muscle cells in ways that gentler walking did not. Mitochondria affect how cells make and utilize energy. Healthier mitochondria should contribute to more efficient movement.
Of course, these studies were single snapshots of people’s lives, and do not show that running or cycling directly caused people to be efficient walkers, only that the activities were related. They also did not look at middle-aged people and whether different types of exercise then might affect how well people walk later.
But Dr. Ortega says he believes the studies’ findings can be both cautionary and encouraging, suggesting that, while any physical activity is worthwhile, pushing yourself a bit now might yield lasting benefits for health and mobility. So, if you currently stroll for exercise, he says, perhaps consider cycling or jogging sometimes, too, if possible. Or add hills to your usual walking route, or, at least for a block or three, pick up the pace.