We all know we need to regularly exercise as part of a healthy lifestyle, but many don’t because they feel that they don’t have enough time in the day to work out. In recent years, a form of exercise called high-intensity interval training (HIIT) has gained attention in both gyms and the scientific literature as a great way to get fit. Essentially, an individual will engage in aerobic exercise at high intensity for short bursts of time between intervals of lighter intensity physical activity. So, how much HIIT is needed to see results?

The answer: four seconds! Yes, a mere four seconds of all-out, maximum exertion exercise when repeated two to three dozen times per session might be all that is needed to maintain or even improve fitness, strength, and power. At least, that’s what a study published in July 2021 in the journal Medicine & Science in Sports & Exercise claims.

The researchers point out that different methods of HIIT have been studied, but the effects of repeated maximal effort power cycling (PC) with very short exercise time—specifically four seconds coupled with short recovery times of 15-30 seconds—might best suit individuals with limited time to exercise. The study group consisted of eleven healthy young adults who trained three times a week for eight weeks using a PC program that included 30 PC sets at four seconds maximum intensity followed by 30 seconds of rest, with rest times progressively shortened to fifteen seconds as the study progressed. By week eight, the PC sessions had fallen to less than ten minutes.

The participants experienced a 13.2% increase in VO2 peak (maximum oxygen intake), a 7.6% increase in total blood volume, and a 17.2% increase in maximal anaerobic power. While further research with larger and more varied study groups is needed, the findings from this study suggest that this HIIT routine may offer a great way to squeeze an effective workout into a busy day.

Of course, consult with your healthcare provider before starting any exercise program to assess your current fitness level and to identify any issues that may indicate a different form of physical activity may work better for your unique situation. If you have aches and pains, your doctor of chiropractic can also provide treatment to help restore normal joint motion and show you stretches you can do at home before and after your workout to reduce the risk of injury as you engage in a new fitness routine.