Garmin Vivosmart 4 review: The best fitness tracker under £120

The Garmin Vivosmart 4, Garmin’s latest fitness tracker, improves on its predecessor by adding a number of new features. The main one is the new “Pulse OX” sensor that measures your blood oxygen saturation levels. Although it’s not medically approved, the technology can help you to better understand what’s going on with your body, especially during sleep.

The other headline feature is is that the wearable can calculate your body’s overall resources – the “Body Battery” measurement – so you know when to exercise and when to rest; a handy feature for fitness novices and enthusiasts alike.

It’s fair to say these are pretty sophisticated features for a fitness tracker that costs little more than £100. Coupled with its slim, lightweight design and the fact it delivers practically everything else you could need to become a fitter version of yourself, the Vivosmart 4 is a shoe-in for a Recommended award.

Garmin Vivosmart 4 review: What you need to know

Whether it’s the right fitness tracker for you, however, depends largely on how you intend to use it. Like the Vivosmart 3, there’s an OLED display but no GPS, so if you want to track the speed and location of your walks, runs and bike rides accurately you’re better off with the older Garmin Vivosport model.

Otherwise, though, the Vivosmart is great for keeping tabs on your overall activity and fitness levels. It has step, calorie, staircase, sleep and stress tracking and also uses your heart-rate data to estimate your VO2 max and fitness age. If you don’t use the built-in activity modes during a workout, the Vivosmart 4 can also automatically detect exercises such as walking, swimming, cycling and elliptical training and log them to the Garmin Connect mobile app.

And if the Vivosmart 4 deems you’re not being active enough, you can be sure it’ll alert you when you need to move. If you’re anything like me, though, this will be the first feature you turn off. It can grate a little on the nerves.

As with all Garmin wearables, the Vivosmart is compatible with both Android devices and iPhones, and it supports a number of smart features including smartphone notifications, music controls and weather and find my phone apps.

Garmin Vivosmart 4 review: Price and competition

Other than its predecessor, the Vivosmart 4’s main competition comes from the Fitbit Charge 3, which at £130 has the benefit of offering connected GPS – where the tracker uses your phone’s GPS to supply position and speed – but offers no stress or SPO2 tracking, or Body Battery equivalent.

If you need a fitness tracker with GPS, though, you’re better off with the Garmin Vivosport or even the much older Vivosmart HR+, which can now be found for £130 or less. And if you’re really into running, cycling or swimming, it’s might be worth making the jump to a dedicated multisport watch such as the excellent Garmin Vivoactive 3 (£180).

Garmin Vivosmart 4 review: Design and display

The Vivosmart 4’s design doesn’t deviate too far from the fitness tracker stereotype in that it’s made up from a rubber strap with a small touchscreen OLED display. Unlike its predecessor the display has decorative metal trim surrounding it and there’s also a dedicated touch-sensitive button below.

Personally, I don’t think this trim adds anything in aesthetic terms but on the black model it’s subtle enough that it shouldn’t actively put you off. As for the dedicated touch button, this is a very useful addition. Where earlier Garmin fitness trackers employed on-screen buttons that eat into the screen real estate, with the Vivosmart 4 there’s more screen available to display the data you need to see.

Navigating the menus can still feel a little fiddly occasionally, at least until you’ve got to grips with the interface, and because of its narrow design not everything always fits on screen quite how you want it to. Notifications, for example, are rotated through ninety degrees so they scroll across the screen vertically rather than horizontally.

However, I found the Vivosmart 4’s screen easy to read in all conditions and, thanks to its auto-brightness setting, you can happily check it in the middle of the night without being dazzled. To preserve battery life, the screen turns off when it’s not in use, but it’s easily activated with a flick of the wrist or a firm double tap.

Despite cramming in more sensors than ever (more on those below), the heart-rate sensor housing is flush with the rear casing of the tracker. And, comfort-wise, the Vivosmart 4 is slim and lightweight enough that if you’re wearing a coat or long sleeve shirt, you’ll probably forget you’re wearing it entirely.

We were sent the Silver with Azure Blue Band version of the tracker, but it’s available with Berry, Gray and Black bands, too, providing you’re happy with the Small/Medium size. If you have larger wrists, you’ll have to make do with all-black model, though.

Garmin Vivosmart 4 review: Fitness-tracking features

With no GPS or even connected GPS – that’s where a fitness tracker uses your phone’s GPS radio to track your position – the Vivosmart 4 is aimed primarily at users who want to get fitter and have insights into their progress without worrying about the finer details such as how much time they’ve shaved of their latest 5k run. And, in many ways, it’s all the better for it.

The headline new feature, Body Battery, is at the centre of everything. Calculated using a combination of data, including heart-rate variability, activity levels and sleep quality, Body Battery gives you a score between 1 and 100 to tell you how much you have left in the tank in energy terms at any given moment.

Based on this info, you can gauge whether it’s a good idea to lace up your running shoes or whether you’d be better off taking it easy. That’s the sort of data that’s as useful for those taking up a new fitness regime as for those who have been doing it for years.

Although the technology is still in its infancy, after wearing the tracker for a few days, the numbers generally matched up with how I was feeling and how active I’d been. I’ll update this review over the coming weeks once I’ve had a chance to see how Body Battery responds to longer, more intense workouts as well as shorter amounts of sleep but, so far, it looks like an elegant solution to interpreting the mounds of data thrown at you by fitness trackers.

And, just because there’s no GPS, it doesn’t mean the Vivosmart 4 is no good for tracking workouts. There are built-in apps for walking, running, strength training, cardio, pool swim, yoga and more. The only glaring omission here is cycling, but this is one of the many exercises the tracker’s Move IQ technology can automatically detect and log to your timeline.

For walking and running, when the Vivosmart detects you’ve been moving for more than a set amount of time, it automatically starts a timed activity for you. Distances are estimated but with the option to set custom stride lengths, you have a pretty good insight into all the key metrics you could ever need such as distance, pace, speed and heart rate.

Swim tracking is a new feature to the Vivosmart series and it’s a welcome addition for those who like spend hours racking up lengths at their local pool. Unlike the Fitbit Charge 3, which is limited to showing the exercise duration on screen, the Vivosmart 4 displays a lap count. Both times I tested the swim mode, however, this figure ended up being one or two laps out for every ten lengths or so. That’s not great, but you can at least manually correct it both during and after the workout and you’ll always have a rough gauge of how much distance you’ve covered.

Garmin Vivosmart 4 review: Pulse OX sensor and sleep tracking

The other new standout feature for the Vivosmart 4 is its Pulse OX (SPO2) sensor, a feature only seen in Garmin’s premium smartwatches until recently. Although Garmin offers a disclaimer explaining it shouldn’t be used as a medical device, the sensor gives you insights into something that is irrefutably medical in nature: the oxygen saturation of your blood.

Unless you’re hiking at high altitude, it’s not really clear why the average person would need to check this info during the day but the Vivosmart 4 gives you the option to do so. Readings of 95% or higher are considered normal and each time I used the feature, it came back within this range. So far, so good.

Pulse OX can also be enabled during the night, which makes a little more sense because low blood-oxygen levels can help to identify conditions such as sleep apnoea. Although my average SPO2 was again within the normal range, the tracker did sometimes record lows of between 80% and 90%. As the Garmin Connect app explains, such low readings can be caused by anything from loose fit to lying on your arm and restricting blood flow. Unless your SPO2 levels are consistently in this range at night, then, they’re probably best taken with a pinch of salt.

Sleep tracking on the Vivosmart has also received an upgrade, bringing it more in line with Fitbit’s Sleep Stages insights. Instead of simply logging deep and light sleep, the tracker now measures deep, light and REM stages and you can see how much you moved at any point during the night, too. Although it can be fascinating poring over this info (it also contributes to the Body Battery calculations), Garmin doesn’t offer any details about what the normal ranges are for different sleep stages, as Fitbit does.

Garmin Vivosmart 4 review: Performance

Unlike the Fitbit Charge 3, which suffers from a laggy, unresponsive display, the Vivosmart 4 is an absolute pleasure to use. Swiping between screens is quick and easy and the touch-sensitive button works reliably, providing the display isn’t covered with water, which can be a problem in the pool.

Smartphone synchronisation is quick and dependable and walks and runs automatically logged by the tracker are uploaded to Strava without you even having to open the app (assuming you’ve linked it to Garmin Connect). Notification delivery, too, works well. You can choose which app’s notifications are sent to the fitness tracker so not to be bombarded constantly and I found they always arrived promptly.

As for battery life, Garmin promises up to seven days between charges, although that figure will drop by a few days if you choose to enable Pulse OX at night. If anything, however the Vivosmart 4 seemed to exceed those estimates. After three days of use with Pulse OX activated, the battery indicator icon still had three of its five bars filled, so I’d expect it to reach six days with the SPO2 sensor enabled and yet more still without it.

Garmin Vivosmart 4 review: Verdict

There are a few things that prevent the Vivosmart 4 from gaining a five-star review and Best Buy award, namely its lack of GPS and cycling mode. Plus, you can easily make the case that its rivals such as the Fitbit Charge 3 are better looking.

However, if you’re not looking for a device that lets you track outdoor activities to the nearest ten metres, Garmin’s Vivosmart 4 does everything you could ask a fitness tracker to do.

With automatic activity, sleep and stress tracking, it builds a detailed picture of your overall fitness and health that its rivals simply can’t match. Crucially, this wealth of data is summarised in bite-sized form in the excellent Body Battery score, which can inform your exercise schedule, so you get fitter without over-training.

Consider that the Vivosmart 4’s smart features are more reliable than those of its main rival, the Fitbit Charge 3, and there’s no question which device I’d recommend. The Garmin beats the Fitbit on pretty much all counts.