Almost half of American adults fail to get enough physical activity.
Health experts generally advise 75 to 150 minutes of exercise each week, citing well-established benefits that include a longer life, lower obesity rates and reduced risk of chronic disease.
For people balancing work, family and other demands, finding that much time can seem unrealistic. Long gym sessions can also place considerable strain on the body.
Now, researchers say a workout lasting only three minutes could produce powerful benefits. Brief, intense bursts of exercise may encourage healthier aging, protect against disease and support weight loss more effectively than 90 minutes of moderate activity such as cycling or swimming.
Their new study found that just three minutes of sprinting prompted molecular changes throughout the body. The workout increased beneficial blood proteins associated with reduced stress on the heart and improved fat metabolism.
Researchers in New York City followed participants for eight weeks, comparing people who completed three or four weekly sprint-cycling workouts lasting three minutes with a group that cycled moderately for 90 minutes.
The short, high-intensity sessions immediately stimulated a rise in more than 200 proteins known as exerkines. These molecules have been linked to the growth of blood vessels, tissue repair and hormonal signals involved in breaking down fat.
In contrast, only a small percentage of proteins changed noticeably after 90 minutes of moderate cycling, and some of the beneficial alterations did not appear until three hours later.
A recent study found that just three minutes of sprinting can trigger molecular changes in the body, increasing helpful proteins into the blood that are linked to heart health and protection against obesity and diabetes
Although the experiment focused on cycling, the researchers said comparable bursts of effort could involve running, climbing stairs or performing bodyweight movements such as burpees.
Brief bouts of vigorous exercise are believed to raise the heart rate rapidly, prompting the heart to pump blood more forcefully and deliver oxygen to active muscles. That process may accelerate calorie burning while helping the body adapt to physical stress and recover more efficiently, potentially lowering injury risk.
Longer sessions at a moderate pace, meanwhile, can create greater physical wear and tear. They may deplete energy stores and contribute 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,’ 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, said.
‘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 volunteers performed six all-out cycling sprints, each lasting 30 seconds and followed by four minutes of recovery. The remaining nine participants cycled continuously at moderate intensity for 90 minutes.
Afterward, scientists examined blood samples from both groups to measure the immediate effects of the workouts on protein levels.
The analysis identified 2,884 proteins in the blood. These compounds function as microscopic messengers, transmitting signals that can affect blood vessels, muscles, hormones and metabolism.
Immediately after the sprint workouts, almost one-quarter of the proteins had changed. Many were associated with lower risks of obesity, type 2 diabetes and accelerated biological aging. Among 33 proteins linked to reduced disease risk, 32 responded to the sprint exercise.
The moderate-cycling group showed a far smaller immediate response: fewer than 0.25 percent of proteins changed after the 90-minute workout.
Some proteins linked to lower metabolic disease risk appeared later, but it took about three hours. Of the 33 proteins associated with lower risk, only three were altered after moderate exercise.
The findings do not mean moderate exercise was ineffective. Instead, its effects appeared to unfold more slowly
Researchers say the rapid changes may be driven in part by ectodomain shedding, a process in which cells release pieces of proteins into the bloodstream, allowing them to quickly send signals around the body.
Sprinting also appeared to send a stronger, faster signal to fat cells through the bloodstream.
Exercise is already known to send signals from working muscles to other parts of the body. But when researchers exposed human fat cells to blood taken after sprinting, the cells showed major changes in how they processed fuel and responded to hormones.
The findings could help explain how intense exercise affects fat metabolism.
Blood taken after moderate cycling caused much smaller changes in the fat cells.
The findings could help explain how intense exercise affects metabolism and how the body uses and stores energy. While the study did not measure weight loss, these changes could potentially play a role in the metabolic benefits of exercise linked to a longer lifespan.
Since this study was limited to 19 subjects, researchers then compared the proteins that changed after exercise with health data from more than 53,000 people in a UK health research database.
Many of these proteins were associated with a lower risk of cardiovascular and metabolic diseases. More than 25 percent were associated with slow biological aging.
But the findings do not mean moderate exercise was ineffective. Instead, its effects appeared to unfold more slowly.
Researchers cautioned that more work is needed to understand how these molecular changes translate into long-term benefits. The study analyzed the body’s short-term response to different types of exercise, meaning 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,’ Luke Olsen, study author and postdoctoral fellow at Rockefeller University, said. ‘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.’
