High intensity interval training (HIIT) will kick your ass, test your mettle, and make you feel sweaty in weird places. But it’s completely worth the effort because this form of exercise is an effective way to build muscle, torch fat, and become a stronger, healthier person — in less than 30 minutes per workout. Seriously.
I first encountered the sheer exhaustion of a HIIT workout on my high school swim team. Before league finals during my senior year, we had to go through Hell Week — a series of workouts designed to push our bodies and our minds to their limits. During one particularly hellish series of sprint sets under the late afternoon sun, I remember feeling like my legs were kicking through layers and layers of mud. My shoulders quaked with each unforgiving stroke.
That’s what it really felt like: a quaking in my burning muscles as I forced myself to keep moving, chasing that elusive break at the end of the sprint when I could finally breathe again.
Why would anyone want to put themselves through HIIT? It gives you a killer feeling of accomplishment by proving just how powerful your body can be — and it teaches you to keep moving forward.
But like a swimmer is lost without a good pair of goggles, HIIT just isn’t the same without some form of fitness tracking. Fortunately, there are plenty of devices you can use to help you become a lean, mean, high intensity interval training machine. Wearables can get you there. Here’s how.
What Is High Intensity Interval Training?
High intensity interval training involves quick bursts of activity followed by rest periods. However, the only way to truly benefit from HIIT is to individualize your training sessions. Sure, you can walk into a gym without a plan and get some work done, but it’s better to know exactly what you’re doing in order to maximize your time.
During a proper high intensity interval training session, your workout should peak at around 70% to 90% of your maximum heart rate during short intervals of extreme activity. During your rest periods, your heart rate should drop to 60% to 65% of your maximum heart rate.
How To Calculate Maximum Heart Rate
In order to calculate your max heart rate for high intensity interval training, subtract 220 from your age. Your maximum heart rate will change as you get older, which is why HIIT is such an individualized form of exercise — and why you should calculate your heart rate before you begin getting your mega-gains.
If you’re 35 years old, your maximum heart rate is approximately 185 beats per minute. That means that your target heart rate should hover between 130 to 167 beats per minute during your high activity periods, and approximately 111 to 121 beats per minute during your rest periods.
Seasoned athletes may be able to hit the 90% max heart rate range, but a more reasonable target — especially if you’re just starting out — is to stay below 85% of your max heart rate.
If you want to get more specific, the Journal of the American College of Cardiology published a study in 2001 that takes the formula a step further: 208 - (age * 0.7). According to that formula, the maximum heart rate for a 35 year old is approximately 184 beats per minute.
Keep in mind that workout intensity varies dramatically, even when people are performing the same HIIT program. Kathryn Weston, an exercise scientist at Teesside University, tells ScienceNews, “It’s about relative intensity to the individual, not absolute intensity.”
What Are The Benefits Of Interval Training?
It’s true that HIIT workouts will make you work harder than just walking on a treadmill for an hour, but the benefits are huge — and you don’t have to bust out your heart rate monitor every day in order to benefit from high intensity interval training.
Here’s what high intensity interval training can do for your health:
- Reduce the risk of type II diabetes by keeping your blood glucose levels within a healthy range
- Improve the maximum amount of oxygen that your body consumes — a common measure of cardiovascular health
- Increase muscle endurance, making it easier to workout
- Improve blood pressure and cholesterol levels
The American College of Sports Medicine recommends working out three to five times per week for 20 to 60 minutes per session at a somewhat difficult intensity, so it’s easy to incorporate HIIT workouts once or twice into your routine.
You can make almost any exercise a HIIT workout, whether you’re interval running, boxing, or lifting weights — as long as you stay within your target heart rate zones, you’re in the clear. What’s more, most HIIT workouts are designed to last less than 30 minutes, so you can knock out some exercises during your lunch break and feel like a champ throughout the rest of your day.
However, you’ll only reap the benefits of HIIT if you monitor your heart rate during your workout, and wearable devices can help you stay within your target ranges without interfering with your routine.
While chest strap monitors will give you the most accurate heart rate reading, we’re focusing on wrist-based devices solely because they’re more convenient — and they offer a greater range of features.
Here are some of our favorites. Learn how they can help you become a HIIT master — and if you don’t see a wearable you love, tell us about it in the comments.
HIIT Watches For High Intensity Interval Training
For HIIT, you’ll need a HIIT watch that will show your heart rate in real time — which means that you need an easily readable screen. The wearables below are prime options because they recognize a variety of exercises and clearly show you the information you need to become a HIIT pro.
Sure, it looks a little bit like a Tetris block gone rogue. But Atlas is a powerful fitness tracker that can automatically recognize an impressive range of exercises, and it can even tell the difference between a dumbbell curl and a kettlebell swing.
- Heart rate: Optical sensors with live updates of your heart rate and a workout summary
- GPS: No
- Battery life: Three to five days with one hour of workout time per day
- Ideal for: Gym-goers who want their tracker to recognize a range of workouts — without all the bells and whistles of other fitness trackers
Fitbit Blaze, $199.95
A big screen, on-screen workouts, music control, and call, text, and calendar alerts make the Fitbit Blaze an all-in-one choice among interval training watch options.
- Heart rate: Fitbit’s PurePulse heart rate monitoring visualizes workouts within three zones: fat burn, cardio, and peak
- GPS: No, but it can track GPS with your smartphone
- Battery life: Five days
- Ideal for: People who want a sleek, multi-function wearable that can track their activities throughout the day with smartwatch features
Fitbit Charge HR, $149.95
For wearable users who want Fitbit’s 24/7 PurePulse monitoring, sleep tracking, and activity monitoring without the extra smartwatch features, the Fitbit Charge HR is a great choice. Its screen will give you a live reading of your heart rate, and the app records your stats for you to view long-term trends.
- Heart rate: PurePulse heart rate monitoring
- GPS: No
- Battery life: Up to five days
- Ideal for: Fitness enthusiasts who want to track their activities and heart rate throughout the day
Waterproof Wearables For High Intensity Interval Training
Any one of these devices below would make a great interval training timer for just about anyone. But for swimmers specifically, a waterproof wearable is a necessity (I mean, obviously). These wearables will show you your heart rate, recognize a variety of exercises, and survive laps in the pool — even during Hell Week. No word on the weird watch tan line you’ll get, though.
TomTom Spark Cardio + Music, $199.99
Even if you’re not a swimmer, you’ll want this fitness tracker because it does everything. Leave your phone behind because this GPS-enabled device can hold up to 500 songs. Just hook it up to your Bluetooth-enabled earbuds, and leave the world behind.
- Heart rate: Built-in heart rate monitor
- GPS: Yes
- Battery life: Up to three weeks with activity tracking, up to 11 hours with GPS, and up to five hours with GPS, heart rate monitoring, and music
- Ideal for: Swimmers and multi-sport athletes who want a powerful, GPS-enabled fitness tracker
Polar A360, $199.95
The Polar A360 gets a special nod because it looks both glamorous and totally wearable. Enjoy live heart rate monitoring on a big, colorful screen, and use Polar’s Smart Coaching feature to get instant feedback on your workout routine.
- Heart rate: Built-in heart rate monitor with target heart rate goals
- GPS: No
- Battery life: Two weeks
- Ideal for: People who want an elegant, swimmer-friendly wearable with live coaching features and sleep tracking
Garmin Vivoactive HR, $249.99
While Garmin is known for its exhaustive line of quality wearables, we’re particularly fond of the Vivoactive HR because it does a little bit of everything. It’ll automatically recognize when you’re working out, and it has apps for everything from swimming to paddle boarding. As an added bonus, you’ll get to view smartphone notifications on the watch’s color screen — the price is steep, but the features are stellar.
- Heart rate: 24/7 heart rate monitoring
- GPS: Yes
- Battery life: Eight days in watch/activity tracking mode, and 13 hours using GPS
- Ideal for: Multi-faceted fitness aficionados who want a waterproof watch with powerful heart rate monitoring features — and smartwatch notifications
Mio Fuse, $129.00
Mio Fuse is a low-cost fitness tracker that does everything you want an activity tracker to do — it tracks your sleep quality, daily activity, and goal progress. Downside: it takes up a lot of wrist space, so while it’s great for workout tracking, you might not want to wear it 24/7. But it’s perfect for data-driven exercisers because it vibrates when you’re working within your target heart rate zones.
- Heart rate: Optical heart rate monitoring with target zone alarm
- GPS: No
- Battery life: Six to seven days with one hour of workout time per day Ideal for: Gym-goers and swimmers who want a wearable with a powerful optical heart rate monitor, but don’t necessarily care about aesthetics
Ready to get moving? Do you have an interval training watch you love? Tell us about your experience with HIIT below.