High-intensity sprints can trigger molecular changes in the bloodstream

We all know a sprint feels different than a longer, take-it-slow kind of workout.

Your heart is pounding. You gasp for air. Maybe your muscles burn.

Now, new research reveals this kind of high-intensity training provokes a remarkably robust response throughout the bloodstream. The training substantially mobilizes more proteins and other molecules in the hours after exercising.

The findings were published by a team of scientists in the U.S., Australia and Sweden. The results do not mean that sprint workouts and other forms of high-intensity interval training, or HIIT, are better than moderate exercise where your heart rate remains at a steady level.

But the data does suggest that pushing yourself in these all-out, short bursts of effort may yield unique benefits for health and fitness, according to Dr. Paul Cohen , whose lab at Rockefeller University led the study, which recently appeared in the journal Cell Reports Medicine .

In a series of experiments, Cohen and his colleagues collected blood from young, healthy adults before and after they exercised, and combed their blood for thousands of proteins and other metabolites.

For example, participants were divided into two opposing camps: One completed six sets of a 30-second maximum effort on the bike, each spaced by 4 minutes of rest.

When they ran their analysis, it was clear the sprint group had "many, many more changes," explains Cohen. "What we can conclude is that sprinting does have a greater effect on remodeling the molecules in the bloodstream."