Best Heart Rate for HiiT? – An In-Depth Explanation

One of the most frequently asked questions we get in our busy inbox each day is “which is the best heart rate monitor for HiiT?” ….  As always, it’s not that easy to answer. There are certainly some HRM’s that are better suited to HiiT sessions than others, but are there a couple that stands out as the perfect training partners for HiiT’ers?

CardioCritic has reviewed this article ensuring it covers the best heart rate monitors for HiiT training in 2018. If you insist on 100% accuracy then you should stick with CHEST STRAP style HRM, e.g.Polar M400 or Garmin Forerunner 230.

If you want to free yourself from a chest strap and rely on a wrist-based heart rate, then consider the Polar M430 (new May 2017) or Garmin Forerunner 235.

Garmin has released the fitness tracker that raises the bar and sets a new benchmark in this competitive marketplace. The Garmin Vivosport is an awesome bit of kit for anyone looking to a) monitor heart rate from the wrist b) follow a 5 x Heart Rate Zone HiiT workout and c) accurately measure speed and distance with built-in GPS.For HiiT the Vivosport utilizes the traditional 5 x heart rate zones roughly equating to 50%, 60%, 70%, 80%, 90% of MaxHR. It’s discrete, stylish, highly functional and even includes a VO2 max test and 24/7 daily stress test.

best heart rate for hiit

Wrist Based or Chest Strap HR?

Wrist-based sensors work best for steady and consistent heart rate. The nature of HiiT training can affect the accuracy of the heart rate readings.

From my own heart rate accuracy tests I have found the models listed in this article to be approximately 97% accurate for about 97% of the time.

In other words, don’t be surprised if you get the odd spike or drop-out. That said, the new Polar M430 with it’s 6 x LED sensors is one of the best ever tested responding well to sudden and intense heart rate rises and rapid recoveries.

The best Heart Rate Monitors for HiiT

In our opinion the best watches for use while HiiT training is the Polar M430 or the Garmin Forerunner 235

The reason for this is their live display indicates which HR zone you are currently training in (all watches support 5 heart rate training zones).

They also provide detailed post-session feedback of time spent within each HR training zone. All models give this feedback BOTH in the watch unit and via their respective APPs (Polar Flow APP and Garmin Connect)

If you want something more in the style of a fitness tracker please refer to the UPDATE above regarding the Garmin Vivosport

Polar M430 with Heart Rate Zone Bar

Polar M400 for HiiT training
The Polar M430 is an activity tracking, GPS wonder watch.

Polar has two great features for HiiT training – 1) Zone Pointer as shown above, clearly displaying which one of 5 x Polar Sport Zones you are in (these are auto set, but can be manually adjusted) 2) Polar ZoneLock > If you are trying to stay within a single HR zone for an extended period of time Polar’s ZoneLock feature may be just what you’re looking for.

When you are in the desired heart rate zone just press and hold the button to LOCK you into that zone.

When you drift above or below you are alerted (vibrate and audio) . Switching ZoneLock on and off is simple and can be used as many times as you want in a single session.

The older M400 uses the Polar H7 soft chest strap and offers 99.99% accuracy while working out in comfort.

For those looking for total reliability and accuracy when performing HiiT or any other kind of INTERVAL based training we still recommend the use of a CHEST STRAP style HRM. However, the Polar M430 with 6 x LED sensors has proven to be VERY accurate in acquiring heart rate conveniently from the wrist.

Polar M430 – Wrist HR

Forerunner 235 / 230 with Colour Coded Heart Rate Zones

Forerunner 225 with 5 x heart rate intensity zones
If you’re happy to have approx 97% accuracy for 97% of the time then a heart rate monitor with BUILT IN optical sensors is for you.

No more chest strap is a convenience, but you have to be certain you are happy to have the small drop in accuracy/consistency.

Some people will get 97% plus accuracy from these monitors, but the truth of the matter is chest strap styles are the most accurate. Assuming you are willing to take the plunge and go STRAPLESS then we’d recommend the Forerunner 235, If you want the same features but the accuracy of a chest strap, get the Forerunner 230.

Info >> If you’re fairly new to heart rate zone training you may want to know how to calculate maximum heart rate? or possibly what should my target heart rate be when training? That’s why we’ve added some useful heart rate training calculators for your reference and help.

What is HiiT?

Let’s make sure we all know what we’re talking about here.

HiiT, or “High-Intensity Interval Training” is an effective and proven training method for those looking to build strength, improve aerobic fitness, look great and burn fat ALL from a relatively short (duration) training session.

It’s a training session that mixes periods of low/moderate intensity periods with periods of HIGH intensity.

“In research, HIIT has been shown to burn adipose tissue more effectively than low-intensity exercise – up to 50% more efficiently.”  [] and, according to USA Today,  the American College of Sports Medicine reported that P90X and CrossFit (both HiiT training programmes) were the top two fitness trends of 2014.


A word of warning. We would NOT recommend anyone begin a HiiT programme until they can exercise at 65-75% of their MaxHR for 30 minutes or more. Interval training makes great demands on your body, in particular your cardio-vascular fitness.

We would NEVER recommend HiiT training to someone relatively new to exercise or a person who suffers from any exercise affected illnesses or medical issues. If in doubt, TALK TO A PROFESSIONAL.

Do you know your safe training zones?

If you are not familiar with heart rate training then please don’t forget to visit our free Heart Rate calculators page.

We have 2 online calculators to help you determine a safe maximum heart rate (MHR) and, once you  have that 5 x HR training zones adhering to Polar’s SPORTS ZONES format.

These calculators are FREE and should give you a safe guideline for your HiiT training. If you are already FIT and have been training for some time then you may find that they are not as challenging as they could be.

Start with these and feel free to up the limits. If you know your MHR from a graded exercise test then use that in our HR training zone calculator.

Will I have the body of a God/Goddess in a few weeks?

There’s a lot of hype from some websites, as you’d expect, for something that claims to turn your body from couch potato to Adonis/ Aphrodite within a few weeks of short training sessions.

HiiT training for the body of a Greek god
The bottom line is, as with any training programme, you get out what you put in. Don’t go in to this thinking HiiT is 20 minutes of fun each day for the next 6 weeks …. then you’re done for life. It’s not. It’s hard work while you’re doing it, VERY HARD work.

Once you’ve achieved your targets and have the body of a God/Goddess you then need to make sure you manage and maintain it.

The Benefits of HiiT over Traditional Training

I have seen numerous claims on several respected websites that suggest HiiT training burns up to NINE TIMES the fat as more traditional training sessions.

Not only that but it also claims to keep your fat-burning “engines” working at full capacity for up to 24 hours after the training session, burning away the unwanted fat long after you’ve taken a shower and drank your protein shake.

It is certainly true that a 30-minute HiiT session is more effective at burning fat than most other training methods. It is also true that HiiT training results in an elevated EPOC level.

This means you are burning calories POST training, even when resting.

Your tired body is shouting out for food, muscles need repairing and energy stores need replenishing.

HiiT does work. That’s a fact that has been proven by several highly respected academic research groups, but it’s NOT for the faint-hearted and it’s NOT for the untrained, newbie, first-time exerciser.

The person partaking in a HiiT programme should have / MUST have a background in fitness training otherwise it could lead to injury and/or overtraining fatigue issues.

An example of a Typical HiiT session

This example is courtesy of LeanItUp.Lean It UP’s example of a HiiT session will last approximately 15 minutes and works on a 2:1 low to high ratio. What this means is that the LOW-intensity duration is DOUBLE (x2) the HIGH-intensity duration.

  1. Walk 2 minutes as a warm-up (3 MPH)
  2. High-Intensity Interval 1: 45-second all-out sprint. Sprint speed is going to vary on a person-by-person basis. Choose a level that’s intense and makes you run HARD, but at the same time make sure it feels safe. Start conservative and gradually work your way up over time.
  3. Low-Intensity Interval 1: 90-second walking rest interval (3 MPH)
  4. High-Intensity Interval 2: 45-second all-out sprint
  5. Low-Intensity Interval 2: 90-second walking rest interval (3 MPH)
  6. Repeat 3 additional intervals
  7. 2-minute walking cool-down (~2.5 MPH)
  8. Finish

As a word of caution, this version of HIIT is extremely taxing on the body — only attempt it if you’re in the physical shape to handle a highly intense regimen.

Regardless of who you are, start with a conservative intensity and gradually progress to higher speeds.

Extreme Intervals – High Intensity with short recovery

Interval training isn’t new.

It’s been around for decades and was something that the Norwegians and Germans experimented with in 1930. Dr Woldemar Gerschler was a pioneer attempting to base his training methods on solid physiological and psychological principles.

At (Formerly it is something that Tristan and Louise have always used to increase speed and power, whether training for 100m, 10K or full marathon.

The only way to ensure you get the very best from traditional interval training or HiiT is by using a heart rate monitor to ensure you are training at precisely the correct heart rate zone… and also, and VERY IMPORTANTLY, to ensure you are recovered to the desired HR before beginning another interval.

Andrew Wyatt

Andrew Wyatt

Andrew Wyatt has been a tech geek for as long as he can remember. Whether it's laptops, cameras, or projects, he's obsessed with it all. When he's not researching the latest tech products, he likes to go on long hikes with his dogs.

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