An intense two-year exercise regimen, consisting of 5-6 hours per week, reversed up to 20

Well SupportedSustained training for two years at 4-5 days/week in individuals aged 35-65 can reverse the effects of sedentary aging on the heart.

Partially SupportedThe heart tends to get stiffer and smaller, impacting efficiency and exercise capacity, starting around age 50 to 65.

Partially SupportedVigorous exercise in sedentary 50-year-olds can result in hearts with structural and functional characteristics akin to those of 30-year-olds.

Partially SupportedA two-year exercise protocol totaling 5-6 hours per week included Norwegian 4x4 Interval Training (four minutes high-intensity at 95% peak heart rate, followed by three minutes recovery at 60%-75% peak heart rate, repeated four times), recovery day aerobics (20-30 minutes light aerobic exercise), endurance building (1+ hour endurance exercises plus a separate 30-minute base pace session), and strength training (twice weekly).