HIIT (High Intensity Interval Training) see Wikipedia for detailed explanation: https://en.wikipedia.org/wiki/High-intensity_interval_training
Bottom line, shorter, more intense workouts that burn more fat than steady state cardio. Can incorporate almost any type of exercise into a HIIT plan. This article in Bodybuilding links to the studies supporting the findings.
I tried some hit sessions 4 months ago (coming back to exercise after 30 years) and decided to pass and do old fashioned steady state cardio for now. I’m also walking about 5 miles a day 5 days a week and a couple hours a week of lifting. All of those make some contribution to cardio vascular health but figuring out how much that is is problematic. The only measures available are blood pressure, and breathing rate compared to heart rate. May be some HIIT can come later for me when I’ve toughened up some more.
Absolutely! I find that my energy levels are better and I see the best esthetic results when I incorporate HIIT into my regime. Actually, pretty much all my aerobic activity is interval training. I do one 10-12 minute running sprint session, one 15 minute swim sprint session, and one 20 minute stair mill interval per week and get better results from this than I ever did from running 3-5 miles 5 days per week.