Most smartwatches have a fitness component for the very good reason that a watch is moving with you throughout the day. For counting steps, encouraging activity, and tracking occasional long walks, runs, or bike rides, most smartwatches will do fine. If you want a device to track your everyday runs or cycling sessions, you want a GPS running watch. If you’re serious about tracking and improving your movement and sleep, a fitness tracker will do that for less money and look more discrete doing so (and if you have health insurance, you may get a discount or incentives to use one). There are smartwatches that lean heavily toward sports and fitness in their marketing, but there are drawbacks to each of them not found in a dedicated device. At the other extreme, if you all you really need is step counting, a hybrid smartwatch—with an analog face like a traditional watch, but with built-in motion sensors and months-long battery life—may be a better option.
The Passport is versatile in that it works with Android and iOS mobile devices. And it features the ability to make phone calls with its built-in microphone and speaker. You can use voice commands (the Passport leverages your phone's voice recognition system; such as Apple's Siri for iOS devices or Google Now for Android) to control the mobile device from the watch. And because of the analog watch face, you can easily see the time in bright sunlight.
You can also use devices that support the Google Wear operating system in conjunction with an iPhone as well as a Samsung Gear device that runs Samsung’s own Tizen operating system. But Google Wear and Tizen devices are designed to pair with smartphones using the Android OS, so you won’t get full functionality when pairing with an iPhone. For instance, some Android smartwatches carry Samsung’s smartwatch line-up and naturally enough, work best with Samsung smartphones, but are still compatible with Android-powered Huawei or Nokia phones.
"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.
The Apple Watch Series 4 is now on sale, and it's the best smartwatch you can buy right now. The redesigned device, which starts at $399 for the GPS model and $499 for the cellular version, is the best smartwatch you can buy. It has a larger display and slightly bigger case size while retaining the same rounded square design the watch is known for. Even more importantly, Apple received FDA clearance for a new electrocardiogram feature that can take a 30-second EKG and diagnose atrial fibrillation.