If you can work hard enough, you can have anything you want - That’s the American dream. This idea of the grind permeates society so much that it’s led to a surge in high intensity interval training. It’s become THE way to get six-pack abs. Gyms and online promotions promise “only 10 minutes a day to lose 10 lbs in a month!”, and other ridiculous claims.
Most of these are completely wrong.
Not only do they not work, but lots of these high-intensity workouts promote a yo-yo style of fitness. You’re work until you drop, you get hurt, and then you’re forced to take time away from exercise. Now don’t get me wrong - there’s a time and place for hard work. And some people love their HIIT class. As an athlete, I’ve been using intervals as my primary form of conditioning for years, so I’m not trying to knock it completely.
But anyone who says you absolutely must do HIIT to get results is wrong. There are plenty of other ways to successfully reach all kinds of fitness goals. But first, let’s consider what we mean by HIIT.
What is HIIT?
HIIT stands for high-intensity interval training, an exercise method involving alternating levels of effort. In contrast to steady-state exercise, HIIT requires varying periods of work and rest. There’s no “one” way to do it, and as such, it’s become a sort of catch-all term for short, intense workouts of any kind. Boot-camp style workouts of 20 second sprints with 20 seconds of rest and CrossFit AMRAP’s count as HIIT. Both weight training circuits and spin classes fit the bill, depending on how they’re prescribed. As long as your workout pushes your limits towards a brief respite, you’re training high intensity intervals.
Why HIIT has become so popular
To be frank - it works! For most, it’s mentally easier to work hard knowing a break is just around the corner. The harder you work, the more calories you burn, and the fitter you get. If you only have 30 minutes to spare, you can get a lot more done by packing it all in. Plus, most of us are more willing to change our workouts than our diets. As a lot of fitness goals come down to calories in vs. calories out, if everything else stays the same, HIIT puts you closer to a deficit.
However, does working harder always trump working smarter? The single determinant of lifestyle change is consistency, and if you don’t like high intensity training, then you won’t be consistent. Bottom line. So let’s take a look at some of the most common fitness goals, and how you can benefit from alternative training methods.
When people say they want to lose weight, they typically mean losing fat. Unless you compete in a weight class sport, you probably aren’t too concerned about gaining lean muscle mass in the process. In fact - a toned, athletic figure is often the goal.
As I mentioned previously, high intensity intervals are a great way to burn calories. But even the most intense workouts don’t hold a candle to what happens during the other 23 hours of your day. During that time, you’re adding calories through food, but you’re also burning them by simply existing. It takes energy to be a human, and your body uses fat stores to fuel daily activity.
Unfortunately, if you’re stuffing your face with more calories than you can burn (yes, even with HIIT), you’re going to add fat. The quickest way to fat loss is to fix your diet. Period.
In addition to diet adjustments, use regular old strength training. By building lean muscle mass, you shift your body composition. Muscle tissue houses mitochondria, the cellular organelles responsible for fat metabolism. More muscle = more mitochondria = more fat-burning potential at rest. Plus, you can still move at a steady clip during your workouts. No one’s saying you have to do one rep every 5 minutes. Work through your sets and reps efficiently, and you’ll still burn calories at the gym. Only now, you’re also melting that fat away while you watch Netflix.
When trying to get stronger, you need to lift heavy. If you want to get injured, rush through it.
Not only does rushing your big lifts increase injury risk, but adequate rest contributes to greater force output. According to a comprehensive review in the journal Sports Medicine, the best rest period for strength lies somewhere between 3-5 minutes. Researchers found that with heavy loads between 50-90% of one rep max, resting 3-5 minutes between sets increased the amount of reps people could do at a certain weight. People were able to do more volume at a higher intensity. Over time, this correlated with an increase in absolute strength.
Long story short - if your goal is maximum strength, avoid high intensity interval training.
For hypertrophy, research suggests 6-12 reps and between 30-90 seconds rest between sets. Theoretically, you could make this interval training, but people tend to rush through high intensity intervals. They “cheat” on movements and avoid muscle isolation. While it’s great for calorie burning, it’s not necessarily hitting the target areas. Training at high intensities also triggers a stress response. While this is great in the moment (and allows us to push beyond our limits), a chronic stress response limits muscle growth. Therefore, if you want to build muscle, and HIIT is your go-to, make sure to spend a good chunk of time on nutrition and recovery. Or, you could focus on time-under-tension, stimulate growth hormone, and make muscle-building easier.
The most important aspect of reaching fitness goals is consistency. So if you love your boot camp workouts, stick to them! But if you absolutely hate everything about interval training, you don’t need it to get results. Instead, choose an alternative that you enjoy, and trust the process.