A new study from Rockefeller University found that just a few minutes of very intense exercise produced a much larger immediate molecular response than longer periods of moderate exercise.
Researchers compared several types of workouts and found a striking difference between them.
Six 30-second all-out sprints changed almost one-quarter of the proteins measured in the blood immediately afterward.
By comparison, 90 minutes of steady, moderate cycling changed less than 0.25% of those proteins.
Moderate treadmill running produced a stronger response than cycling, but it still affected far fewer proteins than the brief sprint workout.
Intense Exercise Creates a Fast Molecular Surge
The sprint session changed more than 200 metabolites and quickly increased proteins involved in blood vessel growth, tissue repair and hormone signaling.
Some of these changes may happen through a process called ectodomain shedding.
Instead of cells making brand-new proteins, portions of proteins already sitting on cell surfaces can be rapidly released into the bloodstream.
Researchers also exposed human fat cells to blood collected after the sprint workout.
The fat cells responded with widespread changes in gene activity. These changes involved how the cells used energy, responded to hormones and sensed available nutrients.
Moderate Exercise Has a Different Timeline
The response to moderate exercise was much slower and less dramatic immediately after the workout.
After moderate cycling, increases in fatty acids and proteins produced by the liver didn’t become apparent in the bloodstream until about three hours later.
Fat cells exposed to blood from the moderate exercise group also showed relatively small changes in gene activity.
Sprints and Metabolic Health
The researchers then compared the exercise-related proteins with health data from more than 53,000 people participating in the UK Biobank.
Many of the proteins affected by exercise were associated with lower risks of cardiovascular and metabolic diseases.
The connection was particularly interesting when researchers looked at obesity, type 2 diabetes and other metabolic conditions.
Of 33 proteins associated with a lower disease risk, 32 were changed by sprint exercise. Only three responded to moderate exercise.
More than one-quarter of those proteins were also associated with slower biological aging.
The Response Wasn’t Just a Beginner Effect
One important finding was that the molecular response remained after participants had completed eight weeks of training.
That suggests the changes weren’t simply the body’s reaction to an unfamiliar or unusually stressful workout.
Researchers believe the response may be a natural feature of high-intensity exercise itself.
A few minutes of intense activity may therefore trigger a surprisingly broad reaction throughout the body.
Exercise has long been known to produce changes throughout the body, but researchers are learning that the intensity of the workout may influence exactly what happens at the molecular level.
Different forms and intensities of exercise can cause the body to release different proteins and metabolites into the bloodstream.
These substances, sometimes called exerkines, may help explain how exercise produces its health benefits.
The findings suggest that short bursts of vigorous activity can send powerful signals throughout the body, potentially affecting metabolism, blood vessels, hormones and other systems.
That doesn’t mean longer, moderate workouts are ineffective. Rather, the study indicates that duration isn’t the only factor that counts when it comes to how exercise affects the body.
A “sprint,” when it comes to very intense exercise, doesn’t necessarily mean one’s fastest running.
A sprint can also be 30 seconds of all-out effort on a pedaling machine, or dashing up flights of stairs, or rapid jumping up and down on a 12 inch exercise box.
