Three minutes of all-out sprinting changed nearly a quarter of the blood proteins researchers measured immediately afterward.
The sprint workout also triggered changes in more than 200 metabolites and affected how fat cells behaved.
Many of the proteins affected by sprinting were associated with lower risks of cardiovascular and metabolic diseases in a much larger health database.
If the idea of spending 90 minutes on an exercise bike sounds exhausting, new research offers an interesting reason to pay attention to workout intensity – not just workout length.
Scientists at The Rockefeller University found that a few minutes of all-out sprinting produced a much larger immediate change in the bloodstream than a longer session of moderate exercise.
The researchers were interested in understanding how different types of exercise affect the molecules that help organs communicate with one another. These molecules, including proteins and metabolites released into the bloodstream during exercise, may help explain some of the body's health-related responses to physical activity.
Researchers compared sprints with longer workouts
For one part of the study, researchers analyzed blood samples from 19 young, active, metabolically healthy men.
Ten completed a sprint-interval workout consisting of six 30-second, all-out cycling sessions, with four minutes of recovery between each. The other nine completed 90 minutes of continuous cycling at moderate intensity. Blood was collected before exercise, immediately afterward, and three hours later.
The researchers also looked at participants before and after an eight-week exercise-training period. In a separate group, they examined how moderate-intensity treadmill running affected blood proteins.
Additional experiments involved exposing human fat cells to blood collected after exercise to see how the cells responded.
The results point to exercise intensity
The differences were striking. Immediately after the sprint workout, nearly one-quarter of the proteins measured had changed, compared with fewer than one-quarter of 1% after 90 minutes of moderate cycling.
Sprinting also changed more than 200 metabolites and produced an immediate increase in proteins involved in processes including blood-vessel growth, tissue remodeling, and hormonal signaling.
Blood collected after sprinting also caused extensive changes in gene activity when it was applied to human fat cells, including changes related to how the cells process fuel and respond to hormones. Moderate cycling produced much smaller changes in the fat cells.
“What’s exciting here is that just a few minutes of intense exercise can trigger a significant molecular response,” researcher Paul Cohen said in a news release “And we still see it after eight weeks of training, which tells us this response isn’t simply a product of the body struggling to keep up with unfamiliar stress. It may be that the responses we observed are intrinsic to intense exercise.”
The researchers then compared the exercise-responsive proteins with health information from more than 53,000 people in the U.K. Biobank. Of 33 proteins associated with a lower risk of obesity, type 2 diabetes and other metabolic conditions, 32 were changed by sprinting, compared with three after moderate exercise. More than a quarter of the proteins were also associated with slower biological aging.
“It’s well appreciated that different intensities of exercise stimulate distinct body-wide adaptations,” researcher Luke Olsen said in the news release.
“However, the molecular mechanisms linking these intensity-dependent adaptations have remained largely elusive. Our work suggests that exerkines–proteins and metabolites released into the bloodstream following exercise–are highly sensitive to exercise intensity and may be the key mediators of the health-promoting effects of short bursts of vigorous exercise.”