The saying goes that it takes 21 days to build a habit. So kick start your year with this 21-day HIIT challenge to get your heart pumping and torch fat! Get the workout here: paleo.co/21dayHIIT

The saying goes that it takes 21 days to build a habit. So kick start your year with this 21-day HIIT challenge to get your heart pumping and torch fat! Get the workout here: paleo.co/21dayHIIT

Original article and pictures take https://blog.paleohacks.com site