Toronto: Workouts can keep obesity at bay by turning influential stem cells into bone, not fat, boosting our capacity to make blood and improving overall health.

The body's mesenchymal stem cells or MSCs are most likely to become fat or bone, depending on which path they follow. MSCs can also turn into a variety of cell types.

Using treadmill-conditioned mice, a team led by kinesiologist Gianni Parise at the McMaster University has shown that aerobic exercise triggers those cells to become bone more often than fat.

The exercising mice ran less than an hour, thrice a week, enough time to have a significant impact on their blood production, the Journal of the Federation of American Societies for Experimental Biology reports associate professor Parise as saying.

In sedentary mice, the same stem cells were more likely to become fat, impairing blood production in the marrow cavities of bones, according to a McMaster's statement.

“The interesting thing was that a modest exercise programme was able to significantly increase blood cells in the marrow and in circulation,” says Parise.

“What we're suggesting is that exercise is a potent stimulus - enough to actually trigger a switch in these mesenchymal stem cells.”

The composition of cells in the bone marrow cavity has an important influence on the productivity of blood stem cells.

In ideal conditions, blood stem cells create healthy blood that boosts the immune system, permits the efficient uptake of oxygen, and improves the ability to clot wounds.