Is "fit-tech" fit for performance?

As the production and integration of "fit-tech" or "wearable-tech" increases we thought it was about time we addressed wearable tech from a fitness perspective.

Traditional heart rate monitors

Heart rate monitors aren't new. Athletes have been using chest-strap based heart monitoring systems for some time.

The first wireless EKG heart rate monitor was invented in 1977 by Polar Electro as a training aid for the Finnish National Cross Country Ski team.

These monitors work differently than wrist based tech in that they measure electrical signals from the heart, conducted through the skin to the sensor in the chest-strap which is then transmitted to the watch.

Wrist based heart rate monitors

With the increased use of wrist-based optical HR monitors there is more interest than ever in using heart rate to assess performance.

The bad news is that using optical tech on the wrist which measures the speed of blood flow to measure heart rate is seriously flawed. According to leading experts in the field there are too many bones in the wrist, too much variation caused by movement and technical limitations with optical tech to get an accurate reading. Simply put, do anything more than go for a casual stroll and the device simply won't be able to keep up.

This has been my own experience with my own personal use of wrist-tech and that of my clients during our sessions. They are fine at lower intensities but soon lose the plot when the heat gets turned up.

Some of the newer models now have an algorithm for more demanding activities but this misses the point. If you are using a heart rate monitor to assess performance then accuracy is essential or you might as well just guess. It looks like the old fashioned chest strap is here to stay for now.

Any other use?

Another feature of many wearables is the pedometer. My own personal experience of wearable wrist technology is that it isn't as accurate as a simple pedometer worn on the hip and in general there is a great deal of difference between devices. An example of this is the frequent difference of steps measured between my wife and I when walking the same difference.

That being said they do provide you with a visual guide to how lazy you are being during a day and can provide some motivation to get up and move, one of our key lifestyle guidelines.

why use a heart rate monitor in the first place?

As mentioned, chest strap heart rate monitors are by far the more accurate as they reply on more accurate measuring technology; namely electrical signals produced by the heart itself. So if you want to use heart rate monitor read on for a simple guide to using them effectively during a workout.

Using a heart rate monitor

The hearts' role is to pump blood through the body. As energy output increases due to exercise so too does the need for oxygen. As the respiration rate increases so too does the need to transport oxygenated blood to where it's needed while transporting waste products for elimination.

A strong heart can pump more blood per contraction. This is called stroke volume.

How to use heart rate zones

Parentage of Max heart rate zones have been used to assign effort levels for a long time. At best they provide a good starting point but there is room for error.

Max heart rate = 220 - age


  • Zone 1: 50 to 60 percent — This is very comfortable effort. Aim for zone 1 during the warm-up, cool down, and recovery between higher intensity intervals.
  • Zone 2: 60 to 70 percent — “Average” effort; easy enough to still maintain a conversation. Use this for training aerobic maintenance or cardiac output, or the volume of blood the heart pumps per minute.
  • Zone 3: 70 to 80 percent — Above average effort. Ideal for training for improvements in aerobic capacity.
  • Zone 4: 80 to 90 percent — Hard effort, although sustainable. Good for maintaining anaerobic capacity.
  • Zone 5: 90 to 100 percent — As hard as you can go, great for developing anaerobic capacity.

I have personally seen a lot of variation especially in older adults who have an above average fitness level. I remember as a newly qualified personal trainer stopping a fitness test as the subject had exceeded his "maximum heart rate" despite him being on a RPE or 7 and feeling fine.

Using a monitor helps to remove the guesswork from output and recovery. Instead of using time or reps as a measurement of effort you can use heart rate.

For example: You want to maintain a constant output level on a recovery day or for a de-conditioned client, then using a monitor will stop you/them working too hard.

You might want to push into the anaerobic zones with some max effort work then the monitor will tell you when you're there and able to go again when HR reaches a recovery phase (around 115/120 bpm.

For personal trainers using a monitor is also a great way to check if your client is slacking. HR reaches recovery levels? Get back on it. No more "I just need a few more minutes."