Journal of Cardiovascular Nursing, March 2026 | Yu-Hsuan Chang, PhD et al., National Tainan Junior College of Nursing
Visceral fat, the deep abdominal fat that surrounds internal organs, poses more risk to the heart and metabolism than the fat beneath the skin. A new randomized trial finds that for adults with high visceral fat, short bursts of hard exercise strengthen the heart more effectively than steady moderate workouts.
The trial compared two workout styles. High-intensity interval training, or HIIT, alternates short bursts of vigorous effort with brief recovery. Moderate continuous training holds a steady pace throughout. Researchers in Taiwan assigned 31 adults aged 40 to 64, all with high visceral fat, to eight weeks of one style, then eight weeks off, then eight weeks of the other.
Both styles reduced body fat and visceral fat by nearly equal amounts. But HIIT outperformed on a measure called heart rate variability, or HRV. HRV tracks the small changes in time between each heartbeat. Higher variability means the body handles the switch between stress and recovery well. Low HRV is linked to higher risk of heart problems in long-term studies.
Researchers attribute HIIT’s advantage to the way it trains the parasympathetic system, the nerves that manage recovery. Each hard-and-rest cycle appears to strengthen that system over time. When participants stopped exercising, their gains faded quickly. For adults with visceral fat, HIIT may add a layer of heart protection that steady exercise does not.
