If you baulk at having to pay $200 or more for a fitness tracker, take a look at the LifeTrak Zone R420. It does almost everything others do, but at a more affordable price.

It automatically tracks steps, calories burnt, distance travelled and sleep patterns. Its highlight, though, is its ability to measure your current heart rate using its electrocardiogram (ECG) sensor.

Plus, it can measure continuous heart rate via a Bluetooth chest belt heart-rate monitor (HRM), which is not included in the package.

The R420 looks rather plain. It can be easily mistaken for a cheap wristwatch. But its silicone strap feels comfortable on the wrist and is easily replaceable.

It has a small round display and three buttons on its right. The large middle metallic button is the heart- rate sensor. Press and hold this button to get your current heart rate. Pressing it once toggles through your sleep, distance, calories and steps on the display. Double press to activate the backlight.

The top button lets you toggle through workout data, a chart showing step counts, and your daily activity readings. Double pressing the top button will bring you to the watch settings.

Pressing the bottom button once flips the display between one that shows only time, and one with time, date and day. Double pressing this button activates sleep tracking, while holding down the button activates Bluetooth syncing with your smartphone.

It is rather confusing, with each button performing so many functions. Even after using it for some time, I still find myself pressing the wrong buttons.

The small display is always on and shows the time, but it is difficult to see the display under bright sunlight. In dim conditions, the backlighting does not help much.

It was a bit stingy in tracking my steps, posting readings that are 10 to 12 per cent less than corresponding measurements from my calibrated Fitbit Charge HR.

Automatic sleep tracking, though, is very accurate, in terms of pinpointing when I slept and when I woke up.

And, unlike some fitness trackers, it did not register those times when I placed it on the table as sleep. However, it does not pinpoint whether you have light or deep sleep.

Heart-rate measurement using the middle button yields readings that are pretty similar to those on my Apple Watch and Charge HR. At most it differs by four to five beats a minute.

However, unlike Charge HR that continuously measures your heart rate, you need to keep pressing the button to get measurements at regular intervals. A hassle.

The review set did not come with a Bluetooth chest strap HRM, so I wasn't able to test this feature. I think LifeTrak should have a bundle option that includes a Bluetooth chest strap HRM.

On the upside, the R420 uses a standard CR2032 coin battery, which is expected to last for a year. Many fitness trackers in the market run flat in about five days to a week.

•Verdict: If you don't mind a cheap-looking wristwatch as a fitness tracker, the LifeTrak Zone R420 does a commendable job at a modest price.