Are you still Jazzercising or have you hopped onto the newest fitness bandwagon? A worldwide survey conducted by the American College of Sports Medicine (ACSM) concluded the hottest fitness trend of 2014 will be High-Intensity Interval Training, H.I.I.T. This widely popular style of exercise didn't even break the top 20 in last year’s survey before rising to No. 1 this year.

H.I.I.T gets you more fit in less time, makes you smarter, and supercharges your metabolism, but it may not be a smart choice for everyone.

H.I.I.T. workouts usually include short bursts of intense exercise followed by short breaks to recover. The routines can contain an unlimited variety of exercises including body weight training, Olympic lifting, plyometrics (jump training), weight training, and sprints. This style of training has become so popular because the workouts are incredibly effective at transforming the body and usually take less than 30 minutes to perform.

Scientists have also been enamored with the effects of H.I.I.T. A Montreal Heart Institute study found that participants scored significantly higher on cognition tests and had boosted their brain oxygenation after doing just two HIIT workouts a week for four months. Another study at Colorado State University found that thanks to a boost in your metabolic rate, you can burn as many as 200 extra calories in the next 24 hours from only 150 seconds of intense exercise.

Despite its popularity, many health professionals warn that it isn't for everyone.

"High intensity workouts are extremely effective in a short period of time, but they can come with a higher risk of injury,” says Joshua Kozak, founder of HASfit. "Traditionally, these routines are high impact so if you have any preexisting joint problems, then you'll want to stick with low impact exercises. H.I.I.T is also best suited for those with a solid fitness base. If you're just getting started, then this probably isn't for you."

This fitness approach produces what people care about most -- fast results -- so you can be sure this trend is here to stay.

Try this 10-minute H.I.I.T. workout that can be done from home or the gym to burn fat and build lean muscle.

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