A 3-minute sprint session may support longer life — and why it could outdo an hour at the gym

Almost half of American adults do not get enough exercise.

Health experts typically advise 75 to 150 minutes of physical activity a week because regular movement is strongly tied to longer life, lower obesity rates and a reduced risk of chronic illness.

Yet finding time for workouts amid work and family demands can be difficult, and spending long stretches in the gym may also place strain on the body.

Researchers now say a brief, three-minute workout may offer surprising benefits for longevity by helping protect against disease and supporting weight loss more effectively than 90 minutes of moderate exercise such as cycling or swimming.

In a new study, the team found that just three minutes of sprinting can set off molecular changes in the body, raising levels of helpful blood proteins linked to heart health and fat reduction.

Scientists in New York City carried out an eight-week study comparing people who completed three to four weekly sprint-cycling sessions lasting three minutes with participants who cycled for 90 minutes.

The short bursts of intense exercise immediately triggered a rise in more than 200 proteins known as exerkines, which have been connected to blood vessel growth, tissue repair and hormonal signals that help break down fat.

By contrast, only a small number of proteins changed noticeably after 90 minutes of moderate cycling, and some beneficial proteins did not appear until about three hours later.

Although the experiment used cycling sprints, the researchers said similar bursts of effort could also come from running, stair climbing or bodyweight moves such as burpees.

The idea is that brief, vigorous exercise quickly raises the heart rate, helping blood move more forcefully and deliver oxygen to working muscles. That may help the body burn calories faster, cope better with stress and recover more efficiently, which could reduce injury risk.

Longer, moderate workouts, however, can create more wear and tear, deplete energy stores and lead to fatigue, inflammation and tissue damage.

“What’s exciting here is that just a few minutes of intense exercise can trigger a significant molecular response,” said Paul Cohen, the study’s lead author and head of the Weslie R and William H Janeway Laboratory of Molecular Metabolism at Rockefeller University in New York City.

“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 study, published in Cell Reports Medicine, included 19 participants divided into two groups.

Ten people did six 30-second all-out cycling sprints, each followed by four minutes of recovery, while nine others completed 90 minutes of continuous moderate-intensity cycling.

The researchers then examined blood samples from both groups to see how exercise changed their proteins immediately after a workout.

They identified 2,884 proteins in the blood. These molecules act as messengers, carrying signals throughout the body that can influence blood vessels, muscles, hormones and metabolism.

Right after the sprint sessions, nearly 25 percent of the proteins had changed, and many were linked to lower risks of obesity, type 2 diabetes and slower biological aging. Of the 33 proteins associated with lower disease risk, 32 changed after sprinting.

In comparison, 90 minutes of moderate cycling altered fewer than 0.25 percent of the proteins immediately after exercise.

Some proteins linked to lower metabolic disease risk appeared later after moderate exercise, but it took about three hours. Of the 33 proteins tied to lower risk, only three changed after the moderate workout.

The researchers said the rapid response may be partly driven by ectodomain shedding, a process in which cells release pieces of proteins into the bloodstream so they can send signals more quickly around the body.

Sprinting also seemed to send a stronger and faster signal to fat cells through the blood.

Exercise is already known to send signals from working muscles to other parts of the body. But when the team exposed human fat cells to blood taken after sprinting, the cells showed major changes in how they processed fuel and responded to hormones.

That may help explain how intense exercise affects fat metabolism.

Blood taken after moderate cycling caused much smaller changes in the fat cells.

Although the study did not measure weight loss, the researchers said these shifts may help explain how intense exercise influences metabolism and how the body uses and stores energy. Those effects could contribute to the broader health benefits of exercise associated with longer life.

Because the study involved only 19 people, the researchers also compared the proteins that changed after exercise with health data from more than 53,000 people in a UK health research database.

Many of the proteins were linked to lower risks of cardiovascular and metabolic disease, and more than 25 percent were associated with slower biological aging.

Still, the findings do not mean moderate exercise was useless. Its effects simply appeared to develop more gradually.

The researchers cautioned that more work is needed to understand how these molecular changes translate into long-term health benefits. The study looked only at the body’s short-term response to different exercise intensities, so it cannot prove that the proteins released after sprinting directly prevent obesity, diabetes or other diseases.

“It’s well appreciated that different intensities of exercise stimulate distinct body-wide adaptations,” said Luke Olsen, a study author and postdoctoral fellow at Rockefeller University. “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.”