Considering HIIT — or high-intensity interval training — is known to burn fat, improve metabolic health and increase VO2 max levels, you may have jumped on board enthusiastically. After all, it’s known to fire up your gains rather quickly and efficiently. “People like HIIT because it removes one major barrier to not working out: ‘I don’t have time,’” says New York City-based fitness coach Laura Miranda, DPT, CSCS.
HIIT involves alternating between “work” intervals of high intensity with “recovery” or rest periods of lower intensity. Most HIIT workouts call for work periods of 20 to 30 seconds (even up to 90 seconds), explains Craig Weller, exercise specialist at Precision Nutrition. The work to rest radio may be 2:1 (like in a traditional Tabata-style workout), 3:1, 1:2 and so on, he says.
No doubt HIIT is one amazing workout, but there are some aspects of the workout that you may be doing wrong. These mishaps could sabotage your efforts and diminish your results. Here’s how to ensure you get the calorie-torching sessions right.
7 Mistakes That Are Hurting Your HIIT Workout
1. Failing to Warm Up
HIIT is demanding, and it’s not a good idea to pop into the gym right from bed or immediately after sitting for a full day. “At that time, your neuromuscular connections are not firing as well as they should be,” says Miranda. If you skip the warm-up, you may only be able to push at max effort, starting halfway through the workout. (Womp, womp.) Prepare your body with dynamic functional movements that are similar to the moves you’ll do in a workout. For example, slow and controlled side lunges in prep for skater jumps.
2. Planning Long Workouts
When done correctly, a HIIT workout doesn’t have to be long — it can actually last anywhere from four to 20 minutes, says Weller. Miranda caps her clients at 30 minutes per HIIT routine. The catch: You shouldn’t be able to do more than that if you’re truly pushing yourself during the “working” intervals. Schedule a longer workout and you’ll likely hold yourself back during the intense pushes in order to conserve energy. “At a point, you’re getting diminishing returns. You’ll be working out longer but not as efficiently,” says Miranda. Don’t you want to spare a few minutes with HIIT, anyway?
3. Not Going Hard Enough
During the intense intervals, “science shows that you have to push at 80 to 90 percent of your max heart rate to achieve results,” says Miranda. If you don’t have a heart rate monitor, think of this on a rate of perceived exertion scale (or RPE), meaning how hard you feel like you’re working. On a scale of zero to 10 (zero being asleep and 10 meaning your heart feels like it will explode), go for an eight or nine, she says. “You should be extremely breathless, your muscles should be burning, and you know mentally you can’t push any harder,” she says.
4. Forgetting About Recovery
HIIT workouts are hard by nature, but that doesn’t mean you need to short-change yourself on rest. “Most people would often benefit from more recovery time between intervals, so that they’re able to recover well enough to produce a high level of force or intensity during the next work interval,” explains Weller. If you cut off your recovery time, you can’t go as hard when it’s time to crank up the intensity. The result: “a homogenous slog of gasping for breath between half-hearted repetitions,” he adds.
If you typically hate HIIT, this may could explain why. Your recovery period should be long enough to drop your heart rate below about 130 bpm before the next round. It should also be long enough that you can do each work round at full intensity.
5. Picking Complex Movements
During your first work round of a HIIT session, you can probably perform the exercises with proper form and speed. After all, it’s likely you’re not tired yet. But subsequent rounds will increase stress and reduce your motor skill function, says Weller. If you’re doing complex moves, your form can suffer, putting you at a risk for injury. Rather than doing, say, an Olympic lift like a squat clean, go for a simpler goblet squat. “HIIT workouts should be done with exercises that you can perform well, even with your brain turned off,” Weller says. Similarly, if you find you’re sacrificing form at the end, Miranda recommends dropping any weight you’re holding to finish it out.
6. Progressing Too Fast
If you’re choosing a HIIT workout, chances are you’re going all in. But doing too much too quickly can set you up for injury — even during that initial session. “You really need to start slowly and gradually because this allows your musculoskeletal system to adapt,” says Brad Roy, PhD, FACSM, executive director of The Summit Medical Fitness Center and Kalispell Regional Medical Center in Kalispell, Montana. If your first workout is, say, eight minutes long, try 10 minutes the next week. Keep progressing when you can perform the high-intensity intervals at your full capacity throughout the entire workout.
7. HIITing It Too Often
The most important HIIT rule: More is not necessarily more. Try to fit in a high-intensity interval workout like this two or three times per week, says Miranda. “If you’re doing it the way it was designed, you won’t be able to do more than that,” she says. Doing HIIT most days of the week means you run the risk of an ineffective recovery. And an ineffective recovery means you miss out on other aspects of fitness like heavier lifting or flexibility. HIIT is one part of an all-around routine — not the only one.