Are Your Workouts Too Intense? The Pros and Cons of HIIT

POPSUGAR Photography | Benjamin Stone
POPSUGAR Photography | Benjamin Stone

Is there such a thing as too much HIIT? Can you go too hard? Billy Polson, founder of DIAKADI and CSCS, thinks so.

Why? He says it can mess with building muscle and metabolism. "Extreme cardio workouts like 60-minute Spin classes or high-heart-rate-only boot camps are often too much cardio for the body to allow for effective body fat reduction," Billy said. "This intensive volume of cardio will often cause your body to stall its fat reduction, instead reducing your muscle mass and slowing your metabolism."

But . . . does that mean we have to skip our favorite classes? We're not quite ready to let go! Especially because we always feel so good from that endorphin rush and the energy in the room. "I know these classes can be great fun with the high of pushing your body to the limit and the inspiration of the group around you, but I recommend a maximum of only one of these a week," Billy said.

Let's say that we want to keep going to our favorite HIIT classes — but want to avoid the risk of losing muscle from too much cardio. To get another perspective on this, we asked personal trainer and Barry's Bootcamp instructor Erica Stenz for her thoughts, and she agrees that you can do too much HIIT, but there are ways to keep yourself safe.

"As with anything in excess, too much of HIIT training every week can be more detrimental than positive for sure," Erica told POPSUGAR. "But it all depends on your duration, your recovery — like stretching and foam rolling — your nutrition, and your body!"

She recommends HIIT more than once a week, crediting improved muscle memory as not only a benefit of your consistency but also a way to stay safe. "It's important to condition your body for multiple days of high-intensity training every week — that's the main reason why I recommend my clients take at least two to three Barry's classes a week, versus once a week or only once in a while. You will gain muscle memory and strength to prevent you from injuring yourself."

Equinox trainer Kyle Panela says if you're into this kind of group fitness, it's imperative to have a strong base before getting into fast-paced classes. "Stamina, coordination, mobility, strength, and form are all factors that should be determined before jumping into a class," he said, noting that without any prior experience, you could get hurt (hence why Barry's Bootcamp is listed on ClassPass as "Advanced" — they're not kidding!).

Kyle recommends doing a little homework before trying a new class. Is the class advanced? Do you have the strength and skill set to take on this challenge, or do you need a little more practice and fine-tuning? What can you do to prepare? "You should definitely research or even watch the class before you sign up for it," he said. "It's crucial to gain knowledge of certain movement patterns through strength training — hip hinges, scapular retraction, proper squats, and good thoracic, shoulder, hip, and knee mobility — before doing more dynamic or complex movements."

And that way, no matter what schedule you set up for yourself — Billy's recommended one class per week, or Erica's two to three — you're physically prepared to have a safe, fun, effective workout and reap the benefits of the endorphin rush and "high."

Back to Billy's warning of muscle loss: Erica believes this all comes down to nutrition. "For people who are worried about muscle loss in HIIT, I recommend taking a BCAA supplement before their workout to prevent muscle loss, and also drinking a carb-and-protein-packed shake within 30 minutes after the workout [to help with muscle recovery]." She says the best way to achieve your desired results with HIIT training is "with the right balance of nutrition and body maintenance (like stretching, foam rolling, massages, etc)."

Billy maintains that if your goal is weight loss, "Twenty minutes of interval [training], only two days a week is much better for assisting with fat reduction." He understands that it might seem counter-intuitive to what you've been taught: "For many, this idea of reducing cardio to lose fat is a very scary step to try, as most of us are still following the old philosophy that cardio is the best way to burn fat."

If you're still apprehensive, Billy says to give yourself a two-week trial away from your typical cardio schedule. "Do a prior weigh-in and measurements (body fat test included). Then take two full weeks where you nail your nutrition perfectly and remove all endurance cardio sessions that are over 20 minutes long, only doing two 20-minute cardio sessions and four strength-training sessions each week."

He admitted that it might not work for everyone, as everyone's body is different. "Worst-case scenario, you can go right back to your old routine after two weeks if this doesn't work. But trust me, you will see better results."

Our suggestion? Try both. Like we said — everyone's body is different. There's no cookie-cutter plan for everyone. It's also important to note that not everyone's goal is weight loss; in fact, many women are working out to improve their mental health, build endurance and strength, and even socialize. As long as you're listening to your body, staying safe, and consulting with a doctor (and even your trainer), then try these different methods to see what works best for you.