Doing quick, intense bursts of exercise—like sprinting in place or climbing stairs—several times a day can help your heart and lungs get stronger, even if you’re not a regular exerciser. But we’re not super sure yet because the studies are small or messy.

Short bursts of exercise throughout the day—called 'exercise snacks'—might help people who don’t move much get better at using oxygen during activity, but we’re not super sure because the studies are all over the place and not super reliable.

Doing just a few minutes of super-intense bursts of exercise—like sprinting or jumping—several times a day can make you stronger and better at using oxygen, even if you’ve been totally inactive.

If you're a regular exerciser doing cycling, taking a supplement called (–)-epicatechin every day might actually stop you from getting fitter, while people taking a fake pill (placebo) do get fitter over 4 weeks.

When young guys with obesity do a tough workout with short bursts of fast running, their bodies burn more extra calories after the workout than if they jog steadily for the same total energy cost.

In adults with overweight or obesity, aerobic exercise and combined exercise programs improve cardiorespiratory fitness, measured as VO2peak, with aerobic exercise leading to the greatest gains; resistance training alone has little effect on this measure.