Why do fitness professionals vouch for HIIT?

If your New Year’s resolution was to get back in shape, you might consider trying HIIT (High Intensity Interval Training).
Experts say the workout regimen — which involves bursts of intense activity followed by a recovery period — is an effective way to build cardiovascular endurance. When it first emerged in the mainstream, there were concerns that the sheer explosiveness of the workout might be dangerous for novices.
But new research suggests that by slightly modifying the in