You’d have to be living under a rock to not have heard about HIIT, or high-intensity interval training. And chances are you’ve jumped on the Tabata train or have tried a killer CrossFit Workout of the Day (“WOD”). And yeah, HIIT ramps up the intensity of your cardio workout to deliver results in a short period of time.
But that doesn’t mean you should ditch your everyday, easier-paced workouts in favor of all HIIT, all the time. In fact, more moderate workouts provide five rock-solid benefits not to be overlooked.
Reason #1: Variation is What Gives Results
HIIT workouts are a great way to train hard and burn maximum calories in a short amount of time. But they can’t take the place of easier-paced cardio workouts, which create your training base. While HIIT takes mental focus and motivation, lower-intensity workouts give your body—and mind—a chance to relax and simply enjoy a run or ride without red-lining. “If you never have aerobic days, you’ll start to suffer from overtraining syndrome and your gains will start to disappear…or you’ll start to feel stale,” says exercise physiologist Tom Holland, author of Beat the Gym: Personal Training Secrets without the Personal Training Price Tag. “We need those lower-intensity and tempo days, too. Variation is what gives us true results.”
Still feel the need to up the ante on what should be an easier aerobic day? Then instead of increasing intensity, go longer. So if you usually bang out four fast miles on the treadmill, drop your pace and go for a leisurely jog of six or seven miles instead. You’ll still get a challenge without overloading your body.
Reason #2: You’ll Become a Better Fat Burner
Slower cardio workouts train your body to use fat as fuel, says Holland. That’s why endurance athletes spend a lot of time doing slower-paced workouts. Their bodies become more efficient at using stored fat (along with carbs) for energy, which delays hitting the dreaded wall—and means they’re lean, fat-burning machines.
Reason #3: You’ll Get More from your Lifts
While guys tend to be more focused on the “up” or concentric/shortening phase of a lift, the eccentric, or lengthening phase is just as important. Slowing down that phase—say, going up for a count of two and down for a count of four—will produce more results—even if that means you have to drop to a somewhat lighter weight.
Take the focus of how much you lift and focus on how you lift, says Holland. “Slower is always better when it comes to weight training,” he says. “Time under tension is what give results.”
Reason #4: You’ll Have More Energy
There’s a tendency to want to go 110% every time you hit the gym or the roads, but hard workouts can be overly draining—and increase your risk of injury. Besides, easier-paced workouts develop cardiovascular strength—making your heart, lungs, and respiratory system more powerful—and help increase the number, size, and density of mitochondria, the tiny “power plants” in your body’s cells.
And the more mitochondria you have, the more energy you have—whether you’re working out or powering through another late night at the office.
Reason #5: You Won’t Be Starving Afterwards
When you go all-out, there’s a tendency to want to compensate for those extra calories post workout. But following up a hard workout with a couple of beers and a plate of nachos will offset most of your fitness gains. While studies vary, some suggest that lower-key workouts may not leave you as hungry afterwards, and less likely to inhale a fatty meal; one study from the European Journal of Applied Physiology found that men who exercised at lower-intensity weren’t as hungry, and ate less, than those who did sprint intervals.
We’re not bashing HIIT—it’s a great addition to anyone’s regime. But for the highest-quality workouts and the best results, limit your high-intensity work to a couple times a week. “True elite athletes don’t do HIIT every day,” says Holland. “Your training schedule should be about 80 percent pretty low-level, and 20 percent high-intensity…that cycling of intensity is what lets you reap the rewards and stay injury-free.”