3 minutes of sprinting does something 90 minutes of exercise does not

Three minutes of sprinting may produce a molecular response vastly different from the one elicited by 90 minutes of moderate exercise, according to researchers at Rockefeller University. After comparing how the body reacts to varying exercise intensities, they discovered that six 30-second, all-out sprints changed nearly a quarter of the proteins measured in the blood immediately after the workout.

In contrast, 90 minutes of continuous moderate cycling only altered less than a quarter of a percent of the proteins. While moderate treadmill running affected more proteins than cycling, it still registered far fewer alterations than the intense sprint session. The sprint workout also led to over 200 metabolites' rapid increase and elevated levels of proteins tied to blood vessel growth, tissue remodeling, and hormonal signaling.

Some of these proteins may have reached the bloodstream through a fast cell-signaling process called ectodomain shedding, where pieces of already-present proteins on cell surfaces are cut away and quickly sent into circulation. The researchers also tested human fat cells' response to blood collected after sprinting. These cells displayed widespread changes in gene activity, including shifts in fuel processing, hormonal response, and nutrient detection.

Moderate exercise resulted in a much less dramatic immediate reaction, with significant rises in fatty acids and liver-derived proteins associated with endurance exercise demands appearing three hours post-workout. Human fat cells exposed to blood from moderate cycling showed only minor changes in gene activity. The researchers then compared the proteins that responded to exercise with health data from over 53,000 UK Biobank participants.

Many of these proteins were linked to lower risks of cardiovascular and metabolic diseases, with 32 of the 33 proteins associated with lower risk altered by sprinting, while only three were affected by moderate exercise. Over one-quarter of these proteins were also linked to slower biological aging. This suggests that just a few minutes of intense exercise can trigger a significant molecular response, which persists even after eight weeks of training, indicating that this response may be intrinsic to intense exercise rather than merely the body's struggle with unfamiliar stress.

The findings imply that exercise intensity may strongly influence the proteins and metabolites released into the bloodstream, potentially mediating the health-promoting effects of short bursts of vigorous exercise.