In the latest edition of his 4 Minute Fridays newsletter, health coach Dan Go spotlighted a powerful, time-efficient form of cardio proven to reverse biological aging—without medications or year-round effort.

“Want to reverse a decade of aging? You only need 4 months a year,” wrote Dan Go in the post.

He referenced a long-term study of adults with metabolic syndrome, which found that those who followed just four months of high-intensity interval training (HIIT) each year significantly improved cardiovascular health, boosted VO₂ max by 14%, and reduced medication use—all while reversing ten years of cardiovascular aging.

The training method, known as the Norwegian 4×4 protocol, consists of four four-minute bursts of intense cardio with three-minute recovery intervals, performed three times a week for four months. In contrast, participants who did not exercise saw their VO₂ max drop by 7% and their medication use rise by 137%.

Go emphasized that consistency, not intensity, is the key—and that investing just 132 hours a year can slow aging and strengthen the heart. “I don’t know about you,” he wrote, “but I’m willing to do that.”

Dan Go is the founder of High Performance Journal and a fitness and performance coach who helps entrepreneurs improve their body composition, energy, and longevity through science-backed, habit-driven strategies.