Economical running watches that do almost everything: comparing Polar’s M400 and Garmin’s Forerunner 15

Two economical watches that offer a full range of features for runners have recently come onto the market. These are Polar’s M400 (with HRM) and Garmin’s Forerunner 15 (with HRM). These watches appeal to a wide range of consumers because they offer both GPS and heart rate monitoring for “serious” runners—yet they also include the activity monitoring that has become popular with less serious athletes or even non-athletes. Some people enjoy having numbers (on their wrists rather than at their fingertips) that quantify their activity (steps, calories, etc.) and motivate them to become more active.

Garmin Forerunner 15 with HRM

The Garmin Forerunner 15 includes GPS, heart rate monitoring and activity tracking but has a low price tag.

In this article I’ll explain some of the features of the M400 and the Forerunner 15. The M400 is a little more expensive than the Forerunner 15, and I’ll identify some of the features of the M400 that justify this price difference.

I’ll also explain the main differences between two Garmin products, the Forerunner 15 and the Forerunner 220. Many readers will wonder why there is a wide difference in price between these two Garmin watches. Consumers should choose a watch based on the features they need and will actually use, keeping in mind the time and “techie” abilities involved.

Garmin Forerunner 220

Garmin’s Forerunner 220.

Suggested Retail Prices: Polar M400 with HRM $259.99, Garmin Forerunner 15 with HRM $219.99, Forerunner 220 $339.99

Polar M400 with HRM

The Polar M400 is a little pricier than the Forerunner 15 but offers a few more features.

Polar M400—Summary

This watch does GPS, heart rate, and activity monitoring (including sleep monitoring). It has an accelerometer so it can be used for indoor workouts when no GPS signal is available. You can use it as a swim watch too; it’s completely safe and waterproof to a depth of 30m.

Activities you can use it for

 The default settings (5) are running, cycling, other outdoor, indoor, and swimming. (Some of these settings are very similar; for example, the running and cycling settings use different units of pace.) However, you can change the default settings to any five of 100 sports profiles! You can also customize your screen views.

Heart rate information

The watch tells you which of the five heart rate zones you are in. The watch calculates your HR zones by using the default formula HRmax= 220 – age.

Each zone is a percentage range of your HRmax . However, you can change this default calculation if you know your real HRmax .

You can also have the watch calculate your HRmax  by doing the Fitness Test provided on the watch. This requires you to do a short resting test when the watch records your resting HR and your HR variability.

Interval training

The M400 allows you to set up an interval workout with two measurements. They can be measurements of time (i.e. 10-and-1s), distance (i.e. 400m run, 200m walk), or a combination of distance and time (i.e. 400m run, 2 minutes walk or rest). You can set these workouts up on your computer before you start your workout, but you can also set them “on the fly”—that is, on your watch directly when you want to start your interval training.

Back to Start

This feature shows you the way home if you get lost!

Activity monitoring

The M400 does everything that an activity monitor like the Polar Loop does. That is, it allows you to set goals for activity time, number of steps, and calories burned, and gives you daily stats. You can view how what percentage of your daily goal you have reached by glancing at your watch at any time. It also monitors the quality of your sleep (it relies on your body movement).

Battery life

The M400 has a battery life of about 8 hours/charge when in workout mode and about 24 days when used only as a watch/activity monitor.

Garmin Forerunner 15—Summary

Like the M400, this watch does GPS, heart rate, and activity monitoring. You can use it as a swim watch too; it’s completely safe and waterproof to a depth of 50m. It’s also an activity tracker for tracking daily steps, calories, and distance. It reminds you when it’s time to move. It also monitors your sleep.

Heart rate information

Heart rate alerts: You can set alerts to warn you if you go below or above a certain heart rate zone or custom-set mimimum/maximum heart rates. You will get messages and can set the watch to give you audible beeps as well.

The Forerunner 15 has customizable screen. The three default screens show

  1. Time/distance
  2. Pace/calories
  3. BPM/HR zone

Interval training:

The Forerunner 15 has a run/walk feature. Unlike the Forerunner 10, you can set the watch to do any run time and walk time, but this has to be set up before you start your run.

Auto pace/auto lap features

Auto pause means the timer will stop automatically when you stop moving so that only your moving time is shown on the time screen. Your moving time and your real total workout time will be included in your workout summary. You can set the watch to beep at every kilometre or mile and display your time for that kilometre.

Virtual pacer

The watch will allow you to set a predetermined pace and warn you if you are deviating from that pace.

Personal records

You can keep track of your personal records over several typical race distances and your longest run.

History and battery life

The watch stores up to 7 activities. The battery is good for about 8 hours in training mode and five weeks in watch/activity mode.

Comparing the Polar M400 with the Garmin Forerunner 15

Advantages of the Polar M400

  • It has an accelerometer to track distances for indoor workouts. The Forerunner 15 does not, though it can be used for indoor workouts with the additional purchase of a footpod.
  • The Polar M400 has the “back to home” feature that the Forerunner 15 does not.
  • The Polar M400 allows the user to set up interval workouts “on the fly”—in the middle of a run—whereas with the Forerunner 15, all workouts have to be programmed into the watch before the beginning of the run.
  • The M400 can store more workouts on the watch before the workout activity has to be transferred online for a permanent record.
  • The M400 has a slightly longer battery life than the Forerunner 15.

Aesthetics: both watches are small and can be comfortably worn by a person with a tiny wrist. Some customers will prefer the appearance of the Polar; others will prefer the Garmin.

Final comments: The list above makes the M400 sound like the superior product, but it must be remembered that the Forerunner 15 is less expensive, and the customer may not require the extra features of the M400. Also, some customers may prefer the Garmin website and the “user-friendliness” of both the watch itself and the Garmin Connect online site.

Comparing the Forerunner 15 and the Garmin 220

Both are Garmin products, and both include heart rate monitoring and GPS, so why is the Garmin 220 so much more expensive?

Extra features of the 220 include:

  • Full-colour screen
  • Built-in accelerometer
  • 200 hours of workout history in 220 vs. 7 workouts in Forerunner 15
  • Vibration alerts in additional to text messages and audible beeps
  • Live tracking—whereas the Forerunner 15 doesn’t sync directly with the mobile app.
  • Longer battery life; 10 hours in workout mode and 6 weeks in watch mode
  • Autoscroll between screens (rather than pushing buttons), advanced custom workouts and interval training, autosync to your computer, and pace alert (triggers alarm if you vary from a preset pace).

Note about the care of heart rate straps

Heart rate straps should be washed regularly as the salts from sweat can damage the electrodes. The sensor should always be removed from the strap when rinsing or washing the strap. The best practice is to rinse the strap after every workout and to wash it regularly in the washing machine (in a lingerie bag, for example).

For more information about advanced running watches (the Garmin Forerunner 220 and 620, and the Polar RCX5 G5), read my post here.

For a more philosophical discussion, please see my post “Is there really a coach inside the watch?”



About nancytinarirunswrites

I used to be known as a competitive runner, but now I have a new life as a professional writer and editor. I'm even more obsessive about reading, writing, and editing than I was about running. Running has had a huge influence on my life, though, and runner's high does fuel creativity. Maybe that's why this blog evolved into being 95% about running, but through blogging I'm also learning about writing and online communication. I'm fascinated by how the Internet has changed work, learning, and relationships. I love to connect in new and random ways!
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2 Responses to Economical running watches that do almost everything: comparing Polar’s M400 and Garmin’s Forerunner 15

  1. john s says:

    Thank you for the non biased, clear and precise explanations. Only problem is I think it will cost me more money…😁

  2. Great Post
    When I think to buy sport watch then Garmin Forerunner 735XT comes in my first priority. It is one of the most amazing heart rate monitoring watch which can calculate heart rate very accurately. Check out Garmin Forerunner 735XT Review Here .

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