High-intensity kettlebell training “significantly improved aerobic capacity… and could be used as an alternative mode to maintain or improve cardiovascular conditioning,” according to a study from the Journal of Strength and Conditioning Research.
20 minutes of kettlebell training — consisting of 15 seconds of alternating work and rest — can significantly improve aerobic capacity when performed 3 days a week for 4 weeks.
In the JSCR study, subjects improved aerobic capacity by about 6{75938b698c062a5f9d56a28bed7ead9ebf7938f0edec05c365aaf340748e7078} (as measured by VO2max) after four weeks of training.
Kettlebell swings, snatches, cleans, and presses — performed according to the aforementioned work-rest interval — provide for a great total-body strength and cardio workout.
Remember to keep the intensity high (especially if your goal is to improve aerobic capacity), as higher exercise intensities have been shown to elicit greater improvements in VO2max than lower exercise intensities.