By Shannon Fable

High Intensity Interval Training (HIIT), recently named the Top Fitness Trend for 2014 on the American College of Sports Medicine’s annual list, is gaining popularity for its minimal time requirement and fast results.

HIIT workouts can be done just about anywhere and anytime. HIIT isn’t about the exercise, the equipment or the workout location. The name gives away the secret to its success ~ the intensity must be high to receive the benefits. You have to be willing to go harder than you normally do and get a bit uncomfortable.

While HIIT workouts done properly can produce amazing results, going at the wrong intensity level ~ too low or too high ~ can lead to injury or a frustrating lack of progress.

If you’re going to try a HIIT workout, here are five tips to get you started:

1. Start slow and build up.

HIIT asks for high intensity to achieve the results you read about. If you’re just coming back to exercise or have never engaged in a workout program, you need to start by building a cardiovascular base. It shouldn’t take too long, but begin with lower intensity, shorter duration workouts, and gradually increase overtime. Once you can sustain a moderate workout for 30 minutes or more, feel free to explore adding a few rounds of HIIT one to two times per week.

2. Focus on intensity over impact.

HIIT is all about intensity ~ working at an uncomfortable to breathless effort level. Unfortunately, many people falsely assume that impact is the same thing as intensity and tend to add lots of jumping movements to get the heart rate up quickly. Jumping is definitely a way to get the heart rate elevated in a quick period of time, but experiment with alternative ways to increase intensity, such as increasing range of motion. You might find this actually works better and will be gentler on your body in the long term.

3. Play the (workout) field.

When it comes to exercise, monogamy is bad! HIIT is a great complementary workout, but you should still try to cross- train, too. HIIT is primarily a cardiovascular workout designed to torch calories, but your body will benefit from strength-training and core and flexibility workouts. It’s great to complement HIIT with a few group classes at a local gym on your off days.

4. Don’t overdose.

You might become addicted and think that HIIT every day will produce even better results, but the truth is HIIT should only account for approximately 20 percent of your total workout time each week. Two to three HIIT workouts per week (with 48 hours recovery time in between) will produce the best results. You may feel like you can do the workouts every day, but if you’re truly giving the intensity that HIIT requires, your body needs time to replenish before it can go that hard again.

5. Talk more, do less.

You must monitor your effort levels to get the most out of your HIIT workout. Yes, heart rate monitors are a great, objective tool to see if you’re getting into the “zone.” But for quick burst intervals, the talk test can be even better. At the height of your interval, try to talk to a workout partner or speak the lyrics to whatever’s currently on your playlist. You should be at a place where you can only utter one or two words before you need to gasp for air if you’re doing it right. During recovery, decrease your intensity and get back to talking in phrases or short sentences.

Shannon Fable is director of exercise programming for Anytime Fitness. She is the 2013 IDEA Instructor of the Year and was honored as the 2006 American Council on Exercise (ACE) Instructor of the Year. Additionally, Fable is the founder of SFR, a consulting firm for aspiring fitness educators, manufacturers and managers, as well as the owner of Balletone and GroupEx Pro. Shannon is a 15-year fitness veteran and freelance writer, as well as an international presenter for Schwinn, BOSU and ACE. She is a member of the ACE Board of Directors, has helped author portions of the ACE and ACSM group fitness manuals and has starred in more than 25 fitness videos.