Comparing Heart Rate Monitors for Maffetone Training

I admit, I've never been a fan of wearing gadgets on the run. Running for me is a mindful, meditative zen-like experience that lifts my mood and settles my thoughts. I prefer not to have any digital distractions reduce that effect. I don't even listen to music on the run, which I've heard is unbearable for some folks.

Nonetheless, if you want to train with the Maffetone Method—and I do—then a heart rate monitor (HRM) is a must, especially in the early stages. There are plenty of monitors on the market right now, so I thought I would have no trouble picking one up and hitting the road. That turned out to be more difficult than I thought.

The biggest problem I encountered was that most HRMs boast far more features than I needed, such as GPS, calorie counting, cadence tracking, altimeters, fitness plans and the ability to sync data and charts with other devices. That's all well and good, and I'm sure very appealing to some people, but none of those features are the reason I want a monitor. I need it to do two things, and ONLY two things:
  1. Track my heart rate accurately in real time.
  2. Notify me, simply and clearly, the second I move out of my target heart rate zone.
That's it.

The good news is that this eliminates many of the more expensive monitors on the market because their price is usually based on qualities I don't need. The bad news is that it's hard to find reviews for these two simple tasks because most people seem to only care about how many bells and whistles you can cram into a device. I can't believe how many fancy monitors didn't even include an alarm for exceeding your max heart rate—the only feature I really wanted!

Fortunately, I found a couple that get the job done. If you're starting on MAF training, then hopefully I'll save you some of the time and frustration I encountered. Before you dive into it, I have a word of caution...

Beware of monitors that only measure heart rate from your wrist or finger!

Yes, this includes both your FitBit and the finger sensor on your shiny new smartphone, as well as most devices marketed as "24/7 Activity Trackers." These tools work very well measuring your resting heart rate, but as soon as you start moving the accuracy goes out the window (see the research here). Most likely, you'll need to wear a chest strap. Some newer technologies claim to measure your active heart rate accurately without one, and I'll be reviewing one of these devices below, but keep in mind that this is still the exception.

On to the Reviews...

I've been testing two heart rate monitors over the past few weeks: the Polar FT7 and the Mio Alpha. If you're savvy to the world of running technology then you'll know that neither of these is the latest model on the market, though both are still manufactured and easy to find. That's fine with me because the newer devices I considered fell into the category of "more expensive because of stuff I don't need." To be clear, I'm not reviewing these monitors for their overall potential use in all fitness activities, only on how they work for keeping me in my target zone for Maffetone training. As far as I can tell, the FT7 and Alpha both use the same heart monitoring technology as their respective Polar and Mio upgrades.

Also, for the sake of convenience I'm using the term "watch" to describe the wrist devices, even though I'm sure both manufacturers would gawk at that term. They seem to prefer "training computer."

Out of the Box

Polar FT7 Heart Rate Monitor Bundled with H1 Sensor and Chest Strap

The Polar FT7 is one of the more popular and inexpensive heart rate monitors on the market ($89.95 at time of writing). It comes in several pieces and is very much what I expect a HRM to look like: a watch, a chest strap and their H1 heart sensor computer that clicks into said strap. An additional Polar FlowLink transfer unit can be purchased to sync data with other devices, but I had no interest in it. If you're really interested in tracking data, Polar's similar H7 sensor will work with the FT7 watch and also sync with most Bluetooth 4.0 phones—basically the same sensor with a Bluetooth chip added.

I always thought chest strap monitors just measured vibrations of your heart beating, but according to Polar the FT7 sensor is a bit more advanced than that:
It detects... the electric signal of the heart, at the accuracy and reliability of the electrocardiogram (ECG)."
It didn't take long to figure out how everything worked together. Once I had the strap around my chest and the sensor clicked-in, I used the 4 tiny buttons to go through the settings on the watch and set my weight, height, age, sex, max heart rate and upper limit heart rate. Max heart rate is your BPM at maximum exertion, usually told to you by a doctor, and upper limit heart rate is the number you want to stay under while running. Some heart rate training programs use max heart rate to calculate your aerobic zone, but Maffetone's method only uses your age and training history. Obviously, I'm only concerned with the upper limit heart rate and consider the rest of the data settings to be virtually useless.

When everything is set, pushing a button on the watch syncs it with the sensor on your chest. As long as the watch is within a couple feet of the sensor and the chest strap is wet (more on that later), it only takes a few seconds to connect. The watch then shows real time beats-per-minute (BPM) in small digits. One more push of the button officially starts the watch's activity tracking, which then displays BPM in nice big numbers and enables the alarm that signals when the upper limit heart rate is exceeded. Good to go!

Mio Alpha Heart Rate Monitor with Charging Cable
The Mio Alpha, which retails for $139.00, is much simpler because it doesn't use a chest strap. This is one of the newer devices that claims to accurately measure active heart rate from the wrist alone. The folks at Mio explain it like this:
The electro-optical cell in our heart rate sensor 'senses' the volume of blood under your skin. From there, sophisticated algorithms are applied so that your heart’s true rhythm can be detected."
Blah blah blah. In short: no chest strap. The only gear in the box is the wrist unit and a USB charging cable. For you tracking junkies, it will sync with most Bluetooth phones without the need for any additional cables

Light sensor on the underside of the Mio Alpha

When charged, the setup is incredibly easy with only minimal settings. I just had to strap it around my wrist and use the 2 buttons (yes, that's 2 less than the FT7) to set upper AND lower heart rate limits, because this device will set off an alarm when I either exceed or fall below my target zone. Like the FT7, you push a button and wait a few seconds for it to pick up and display your heart rate, then push the button again to start the activity tracker and enable the alarms.

One minor difference from the FT7 is that the Alpha's BPM are displayed in nice big digits in both phases, before and after the official activity tracking. I didn't think that was a big deal at first, but I found it useful for checking my rate during warm-ups when I didn't want the alarm going off for being below my target range. Then again, the FT7 doesn't have a lower range alarm, so it could be in activity mode during warm-ups with the same effect.

Both devices can be used in water. Both have stopwatch features that automatically track how long you're in your activity zone. Both give you data at the end, including average heart rate for the activity period. Only the FT7 comes with a light for running in the dark, though it's a tiny button that's hard to turn on and doesn't stay on for long. I found my night running headlamp to be a better solution for both monitors. From pictures, the Alpha display may look like it would be luminescent in the dark, but it is actually invisible at night.


Since I'm not a fan of gadgets or extra gear to start with, I was skeptical about running with a chest strap. I have to admit, though, the strap holding the FT7's sensor is much more comfortable than I expected. I never felt my breathing was impaired, there was no itching or chaffing, it never slipped or had to be readjusted and since it's so lightweight it was easy to forget about.

As far as the watch goes, I was annoyed with the need to constantly check my wrist—an issue with all wrist HRM displays. This happens constantly in the early stages of Maffetone training when staying within a target heart rate zone is most challenging, to put it mildly. I finally decided it was easier to take the watch off my wrist and carry it in my hand while I ran (as shown in above photo). This way, I can just glance my eyes down from time to time to check my BPM, as opposed to turning my wrist over and tilting my head. That may not sound like much of an inconvenience, but after doing it a few hundred times you may change your mind.

As comfortable as the FT7 strap may be, it doesn't beat not wearing a strap at all. This was definitely a big point for the Alpha. Over time, I really grew to appreciate how quickly I could clasp it on and get out the door.

The benefit of no chest strap, however, is somewhat offset by the need to keep the Alpha on my wrist. It has to be positioned properly to keep tracking my heart, so there was no option to hold it in my hand and check my BPM with a simple glance down like I did with the FT7. That means I'm back to wrist turning and head tilting... over and over and over. Fortunately, the display is nice and big.


Now we're getting into the important stuff, and #1 on my must-have list shown above. After all, what's the point of spending big bucks on a heart rate monitor if it doesn't give an accurate reading?

I'm happy to say that both the FT7 and the Alpha appeared to excel in this category. I say "appeared" because I haven't tested them against an EKG under a doctor's supervision, which is the only way to know with 100% certainty. What I did do is test them against each other by using both devices simultaneously on several runs. I also compared them to a heart rate monitor built into a stationary bike at my local gym. When I had a steady reading, all monitors were within 2-3 beats of each other, usually less. I consider that to be pretty darn good. Honestly, I had already read enough reviews of the FT7 to have confidence in it's accuracy (Polar is, after all, one of the leading manufacturers of HRMs for athletic activity). My skepticism really only concerned the Mio Alpha's new wrist-only technology, and I'm now convinced they live up to their claims. I wish I could show overlapping comparison graphs of both monitors, but since I opted for simple, non-syncing solutions and would need to run with 2 smartphones to do it, you'll have to take my word for it.

That's not the end of the story, though. Like I said, both monitors were in sync when I had a steady reading, and that turned out to be an annoying issue. Surprising to me, it was the FT7 with the traditional chest strap that had problems.

For starters, the strap must be wet for it to read properly. Remember, the chest sensor works by measuring the electric signal from your heart. It needs a good connection to do this, and that means a wet connection. Polar recommends running water over the strap before putting it on and attaching the sensor. I didn't mind that in the summer, but as autumn moved in I really hated putting a cold wet strap around my chest before stepping outside on a chilly morning.

Here's Polar's official tutorial video:

No, there's nothing wrong with your sound settings. It's just weirdly silent.

Sweat also seems to play a beneficial role in getting a good reading, albeit a somewhat gross one. On hot days, when I'd start sweating early on a run I rarely had any drop in my connection. On colder dry days, however, the strap would often dry out during my warm-up before I could work up a sweat. When that happened, the monitor would often jump directly from 117 BPM to 194 BPM and just hang there for a while even if I stopped and stood still. Sometimes this interrupted my workout and frustrated me so much that I was tempted to chuck it into the woods.

Once I'd get warmed up and perspire a bit the crazy BPM jumps stopped and the monitor kept at a steady rate, though "hangs" seem to be a frequent issue, especially in cooler temperatures. For example, if I exceed my upper limit and hear the alarm go off I'll slow down to a walk, but the FT7 will stay on the same high number for several seconds while the Alpha counts down. Then, the FT7 instantly jumps down 8 BPM and meets the Alpha's reading. In this regard, I find the Alpha quicker to respond with real-time data while my heart rate slows down, and therefore a better reference for when I should pick up speed again. Those FT7 "hangs" would result in allowing my rate to dip unnecessarily low and sometimes out of my zone.

On the other hand, the Alpha always seems to lag a few seconds behind the FT7 when my heart rate increases. Whenever I exceed my upper limit, the FT7 is always the first to tell me. The Alpha doesn't hang in the same way, meaning its display isn't stuck on a number that suddenly jumps up 8 BPM. Instead, the reading is always changing and slowly increases until it catches up with the FT7. It just takes its time doing it. That's frustrating because its easy to end up well above my upper limit before I receive any notification. Setting the upper limit alarm a couple beats lower is an easy solution, though it means I'll hear the alarm more frequently.

I did have some odd hangs and readings my first time using the Alpha, but I quickly learned I needed to tighten the strap and make sure it was positioned in the right spot below my wrist bone. Once that was done it worked perfectly, and I never had any issues with it sliding around or losing the reading. Mio warns that it you may need to do a little warm up before getting a good reading, and that excessive bending of the wrist may interfere with it, but neither of these issues came up in my experience.

So, the FT7 is better for counting up and the Alpha is better for counting down. I didn't expect it, but I have to say I prefer the Alpha for accuracy. Despite the problem with lagging a bit, I decided I like that the numbers keep moving. The FT7 hangs just left me clueless as to where I stood. You may feel differently, but I think slow moving numbers are better than no numbers. I also came to expect the Alpha's lagging and quickly learned to keep my speed at bay when the numbers start to rise.


This is #2 on my must-have list. While accuracy is essential, the whole point of wearing a HRM is to notify me when I'm out of my target zone. I want that notification to be simple and clear.

Like I said, the FT7 allows me to set an exact number for my upper limit, and the alarm is supposed to go off as soon as my BPM move above that number. This works... for the most part. Sorry to say I have two issues with this alarm.

Firstly, it often doesn't go off until I've been over the upper limit for several seconds. I assume this is intentional so that it won't be annoying if I exceed the number for only a moment. I don't like it, though, because I often find myself way above my target zone before hearing any signal. This more or less negates the advantage of the FT7 tracking an increasing heart rate so quickly, as described above. After enough late alarms I unconsciously developed a habit of checking the watch constantly rather than depending on getting a timely warning from it. 

Secondly, the volume of the FT7 alarm is low and easy to miss. I have to listen closely and keep my ears tuned to the noise to hear it. If there is traffic, lawn mowers or barking dogs nearby then I may not hear it at all—also very frustrating, since that's kind of the whole point.

I'll add that despite these complaints, the FT7 works for my purposes as long as I stay attentive to it. It just isn't the most ideal. I didn't realize that until I got my hands on the Alpha, which totally nailed the alarm system.

Not only is the Alpha quick to alert me anytime I move past my limit, but it uses multiple ways to do it: a light flashes, beeps go off and the display changes.. all with variations depending on the situation.

I hear a high pitch beep if I'm above my range and a lower pitch if I'm below it. If I'm within 10 beats above or below then I hear one beep repeated every few seconds. If I'm more than 10 beats out of zone, I hear double beeps. Also, a warning light flashes red if I'm above my zone and blue if I'm below it (green when I'm in it). Up or down arrows also appear on the screen when the alarm goes off, but they're not even necessary at that point. The audio alarm is loud, noticeable and pretty hard to miss.

I never thought about needing a warning for getting too far below my target zone before using the Alpha, but I've grown to like it. The biggest challenge with starting out on the Maffetone method is keeping your heart rate under your upper limit, but you also don't want to go more than 10 BPM below it and I've found the extra alarm to be useful.


Neither of these devices are difficult to care for, though they both require some attention.

Polar recommends washing the FT7 strap after every use. I learned the hard way that keeping it clean also keeps it reading accurately. Plus, it's good to do because the chest strap gets soaked in sweat quickly after a hot run (yuck). They also recommend removing the sensor from the strap to prevent the battery from running down in case there is any residual moisture making a connection.

Fortunately, you can easily replace the batteries on both the FT7 watch and sensor yourself, when needed. Polar claims the watch battery should last 11 months if training 1 hr/day, 7 days/week. The battery on the chest sensor should last through 1500 hours of use.

The Alpha seems to work well whether it's been cleaned or not. Mio recommends washing it regularly with mild soap and water on a regular basis to prevent skin irritation, and they add that both the device and your arm need to dry completely before wearing it again.

As for the Alpha battery, it is rechargeable, but not replaceable. That means that when the battery eventually fails to hold a charge the device will become worthless and you'll have to buy a new one. This is perhaps my biggest disappointment with the Alpha, but it is worth mentioning that Mio claims it will last for 300 charge cycles, which is 5 years if charged weekly. At least that's a long time. To date, I've only had to charge mine once the first day I got it, and I've done at least a dozen runs with it over the past month. The good news is that when the battery does finally wear down, it won't just die on you. Instead, you'll get plenty of warning as you notice it holding a shorter and shorter charge as time goes on. Think of it like your cell phone battery. I'm also guessing that, like a cell phone, by the time it finally becomes unusable there will likely be a better version available.

Mio Alpha charging
As for the charger, it's very simple: just click the device into it (a magnet holds it in place) and plug into a USB port. That can be a USB wall charger, a car charger or a port on your computer. The one annoyance is that the charging cable is very short, barely 2 inches. Not a problem if you're plugging it into your computer, but inconvenient in a wall plug.


Okay, here's the breakdown of the Polar FT7...

  • Great price compared to similar HRMs: $89.95.
  • Accurate tracking, when signal is steady.
  • Quick notice when heart rate increases.
  • Chest strap is comfortable and easy to ignore.
  • Watch can be unstrapped from wrist and held in hand for convenience.
  • Replaceable batteries.
  • Lots of unnecessary features and settings (others may like this).
  • Need extra accessory to sync data (not a feature I care about).
  • Chest strap, while not uncomfortable, is one more inconvenience to deal with.
  • Drops signal if strap becomes dry.
  • Real-time monitoring tends to "hang" when heart rate decreases.
  • Upper limit alarm delays too long before sounding.
  • No lower heart rate limit alarm.
  • Alarm is too quiet.
  • Requires regular cleaning to work properly.
And here's how the Mio Alpha measures...

  • Extremely simple operation and settings for Maffetone training with no unnecessary bells and whistles.
  • No extra cables/accessories needed to sync with phone (not a feature I care about).
  • No chest strap necessary!
  • Accurate real-time tracking with no loss of signal.
  • Better tracking of decreasing heart rate.
  • Allows both upper and lower target zone settings.
  • Simple, hard-to-miss notifications when outside target zone.
  • Low maintenance, aside from regular charging.
  • Slightly more expensive: $139.00.
  • Must stay snugly and properly positioned on wrist for accurate reading—no holding in hand for easy glances.
  • Slower response to increasing heart rate.
  • Must be charged regularly.
  • Battery is non-replaceable.
In the end, the Mio Alpha is the strong favorite for me. I like it better all around, as long as I'm mindful that it will respond a few seconds slower to my increasing heart rate. Setting the upper limit alarm a bit lower solves that problem easily. I'm happy to deal with looking at my wrist over and over for the convenience of leaving behind a cold, wet chest strap on a winter morning.

It's worth mentioning that there are several other heart rate monitors on the market, and more companies seem to be interested in developing monitors that can accurately measure active BPM without a chest strap. I wrote an email to Dr. Phil Maffetone to ask if he had a favorite HRM and received this response from one of his team members:
They all have their ups and downs. Personally, I use the Suunto Ambit3 Sapphire with chest-strap HR, and I find myself constantly glancing at my watch to check my HR (which is fine by me). Our upcoming iPhone app will be explicitly designed to optimize HR training, and to pair with a variety of HR monitors, so you have that to look forward to.
That Suunto device looks nice, but it retails for $600.00. Personally, that's a few hundred more than I want to pay for a heart rate monitor when there are plenty of cheaper options out there. I also use an Android phone, so I may have to wait a while before Maffetone's app is available for me. Darn.

If you've used any other heart rate monitors for Maffetone training and found them to work well, then please share!


  1. Thank you for putting this together, it was very informative and helpful, I feel much more ready to start using the Maffetone method.