"Sport watch" functionality often includes activity tracker features (also known as "fitness tracker") as seen in GPS watches made for training, diving, and outdoor sports. Functions may include training programs (such as intervals), lap times, speed display, GPS tracking unit, Route tracking, dive computer, heart rate monitor compatibility, Cadence sensor compatibility, and compatibility with sport transitions (as in triathlons). Other watches can cooperate with an app in a smartphone to carry out their functions. They are paired usually by Bluetooth with a smartphone. Some of these only work with a phone that runs the same mobile operating system; others use a unique watch OS, or otherwise are able to work with most smartphones. Paired, the watch may function as a remote to the phone. This allows the watch to display data such as calls, SMS messages, emails, calendar invites, and any data that may be made available by relevant phone apps. Some fitness tracker watches give users reports on the number of kilometers they walked, hours they slept, and so on.
That same attractive stainless steel design is here. The 240 x 240 pixel display at the heart of the body is by no means the brightest or most vibrant you'll find, but crucially delivers strong visibility in most workout conditions whether you're sweating it out indoors or outside. However, there is no touchscreen or touchpad here, you'll have to resort to pressing some buttons - that could be a deal-breaker for some, but we're sure it won't be a massive one for most.
The Moto 360 was the first round smartwatch we got our hands (or wrists) on, and the design was a standout, for us. It looks like a traditional watch and fits more comfortably than rectangular smartwatches, but still packs the full functionality of an advanced smartwatch. Like the LG G Watch and Samsung Gear Live, it runs the Android Wear OS, allowing voice commands and pushing relevant information to the wearer.
But smartwatches have the innovation advantage these days as most companies making such devices try to develop features that competitors don't have. As a result, fitness trackers have become a bit stale. And after wearing the new Charge 3 for nearly two weeks to see how well Fitbit's gentle marriage of smartwatch and tracker features turned out, it seems the form factor remains radically unchanged—but that's not a bad thing in practice.
It has all the sensors you might want if you’re an avid runner, but it goes so much further. If you’re a hiker, you’ll love the altimeter, air pressure read-outs, the clock showing the sunrise and sunset times, compass and the indicator of the day’s tide levels. You can also download map data for use offline, meaning if you’re the Bear Grylls type then you’ll be well prepared.
The top smartwatches that debuted at the 2017 Consumer Electronics Show included the Casio WSD-F20, Misfit Wearables Vapor and the Garmin Fenix 5 series. Apple released on September 22, 2017 their Apple Watch Series 3 model which offers built in LTE cellular connectivity allowing phone calls, messaging and data without relying on a nearby smartphone connection. 
Most stores that sell these smart watches feature display models that you can pick up and touch. We recommend getting a feel for how these watches operate before you invest in one of your own. Specifically, you’ll want to know the form of navigation each of these use to go through the various screens, apps, and functionalities. We were partial to twistable bezels and dials, but you might be used to swiping your way through screens.
Inside the Charge 3 are an accelerometer, gyroscope, optical heart rate monitor, and an SpO2 sensor for tracking blood oxygen levels. The Charge 3 is the third Fitbit device to include an SpO2 sensor, following in the footsteps of both the Fitbit Ionic and the Versa smartwatches. However, currently the SpO2 monitor lies dormant inside all of these devices as Fitbit hasn't made use of it yet.
Finally, Wear OS has a problem that’s seemingly random and hard to understand: “Can’t reach Google at the moment.” Having tested at least a dozen Wear OS watches, we can say that an unexplained failure when using voice commands is the most common negative trait for all of them. It’s impossible for the layperson to understand which part of the watch-to-phone-to-Internet relay is falling down, but it can happen at any time, even right after you’ve used the watch to do something else successfully. When Google Assistant is made the center of Android watches, not being able to reach Google Assistant lowers the value of that watch considerably.
For instance, I rarely use the touchscreen on my Fitbit Versa because the shortcuts to my most-used smartwatch features are available via the three physical buttons on the watch. Gesture recognition is hit and miss on smartphone screens, nowhere near as responsive and accurate as on your smartphone screen, so bear that in mind too. Force Touch is a useful feature that has come to smartwatches, notably the Apple Watch. Just press down or tap the screen to activate different features.
Software may include digital maps, schedulers and personal organizers, calculators, and various kinds of watch faces. The watch may communicate with external devices such as sensors, wireless headsets, or a heads-up display. Like other computers, a smartwatch may collect information from internal or external sensors and it may control, or retrieve data from, other instruments or computers. It may support wireless technologies like Bluetooth, Wi-Fi, and GPS. For many purposes, a "watch computer" serves as a front end for a remote system such as a smartphone, communicating with the smartphone using various wireless technologies. Smartwatches are advancing, especially their design, battery capacity, and health-related applications.
Samsung's Galaxy Watch, a Tizen OS watch (starting at $329), is our favorite smartwatch for Android users. In addition to up to four days of battery life and a great design, the Galaxy Watch offers built-in GPS, heart rate sensor, water-resistance, Samsung Pay support, plus a nifty rotating bezel for navigating the interface. You can also download music from Spotify to the watch for offline listening. However, you get far fewer apps than you would with a Wear OS watch.