Kettlebells are great. High-intensity interval workouts are also great. Together

As it happens, kettlebells are more effective than dumbbells for improving aerobic capacity, according to research. The study, done at San Jose University, found that participants who trained for 20 minutes three days per week with kettlebells increased aerobic capacity by 6%, while a group who trained with dumbbells saw no increase. That's because the moves you do with kettlebells are typicallly more dynamic than the ones you do with dumbbells, so you can more easily spike your heart rate, the study authors say.

And by increasing your heart rate, you also increase the number of calories—and amount of fat—you shed during the workout. But unlike running or cycling—workouts typically associated with amping heart rate and aerobic capacity—doing a high intensity kettlebell routine also builds muscle. Talk about saving major time at the gym.

"HIIT kettlebell training is a great way to add cardio to your strength workouts," confirms Felix Bangkuai, a trainer at the Health & Wellness Center at Florida Wesley Chapel. Try one (or all!) of these routines designed by Bangkuai to challenge yourself in the gym, and tourch fat while building muscle and endurance. And if you just can't get enough, you can also try these 5 HIIT kettlebell workouts for fat loss.