The Series 4 now has several new health-focused features, which are very intriguing, including the ability to detect when you fall and even alert emergency contacts if need be, as well as an electrical heart rate sensor that works with an app to alert you to heart health issues. The electrocardiogram (ECG) app has been certified by the Food & Drug Administration, but it's not out yet.
Apple is back with the Apple Watch Series 4, the latest in the smartwatch game that's focused on helping wearers live a healthier lifestyle. Running on Apple’s S4 64-bit dual-core processor and the new WatchOS 5 operating system, it’s twice as fast as its predecessor. Available in two sizes — 40 mm and 44mm — it has a 30 percent larger display than the Series 3 and comes in six different aluminum and stainless steel finishes. New improvements include Walkie Talkie mode and a speaker that is 50% louder than in the Series 3. The microphone has been moved to the watch’s opposite side to reduce noise and create clearer phone calls. The bottom, now made from black ceramic and sapphire crystal for better radio wave transmission, is intended to help with cellular reception and call quality.
Our 19 contenders all promised to give us some distance from our phones by notifying us of incoming calls and texts. But we found that some smart watches were much slower than others at letting us know we had a call. It turns out the quality of the bluetooth connection determines how quickly you’ll be notified, with our worst performers only registering the call with two seconds to spare before diverting to voicemail (yes you, Montblanc) while others simply failed to display any calls at all.

What’s on display?: Most smartwatches have full-colour displays, though the underlying technology will determine how good the screen looks. There has been a move towards AMOLED (active matrix organic light emitting diode) displays, as used in the Apple Watch which present a bright screen, crisp text and accurate colours. Fitness trackers tend to have lower-quality screens and may not present in full-colour, partly to save battery life.

If you want a smart watch that uses cellular data without using up the battery, consider upgrading to the Samsung Gear S3. A close cousin to the Gear Sport, the S3 has all the perks of an LTE smart device (downloading apps, texting, checking email) and, unlike the Apple Series 3, it won’t quit after three hours. In fact, you could feasibly get 72 hours out of this LTE version of the Samsung Gear Sport.
On 9 September 2014, Apple Inc. announced its first smartwatch called Apple Watch to be released in early 2015.[75] On 24 April 2015, Apple Watch began shipping across the world.[76] Apple’s first try into wearable technology was met with considerable criticism during the pre-launch period, with many early technology reviews citing issues with battery life and hardware malfunctions. However, others praised Apple for creating a potentially fashionable device that can compete with "traditional watches,"[77] not just the smartwatch industry in general. The watch only turns on when activated (either by lifting one's wrist, touching the screen, or pressing a button). On 29 October 2014, Microsoft announced the Microsoft Band, a smart fitness tracker and the company's first venture into wrist-worn devices since SPOT (Smart Personal Objects Technology) a decade earlier. The Microsoft Band was released at $199 the following day, on 30 October 2014.[78]
Speaking of music, that's what really sets this smartwatch apart (especially compared to Garmin's other wearables). The Vivoactive 3 Music has enough internal storage for 500 songs — and they're easy to download to your device using the Garmin Express software. Once your songs are downloaded, you can listen to music without a smartphone. Just connect some Bluetooth headphones to the watch and you're good to go. If streaming is more your game, then you can also download some popular media apps as well. 
Samsung treads between smartwatch and fitness tracker, also packing in a heart rate sensor along with that GPS and its much-improved Samsung Health software. There's also the option of LTE (coming soon), if you wish for an untethered connection, with a standalone speaker for taking calls on the watch. It's now waterproof, too, adding swim tracking skills that are on par with the Watch Series 4.
Qualcomm is preparing to launch a new generation of wearable processors at an event in September. That’s likely going to mean new hardware and maybe even new capabilities within wearable operating systems. So at least for the next few weeks, it might be best to hold off on buying any new smartwatches, at least those still rocking a Snapdragon Wear 2100…
Several of them also now support wireless charging which is hugely valuable as you avoid adding yet another cable and cradle to your dresser. Wireless charging pads are on the market that will charge your compatible iPhone and watch at the same time, and Apple is set to release its own official charging pad dubbed AirPower. Wireless charging is also available for Samsung smartphones and smartwatches.
The operating system you choose depends solely on the type of smartphone you have because the smart watch is paired with your smartphone. If you own an Android smartphone, your smart watch should have Android Wear or Tizen. If you own an iPhone, choose an Apple Watch. For example, the Samsung Gear S3 runs Tizen and is compatible with both the Android and iPhone.
Apple Watch Series 3: If you are an iPhone user and generally exist in Apple’s ecosystem, it makes sense to get an Apple Watch. The design quality is exceptional and the Watch makes a nice pairing with your iPhone as materials and design elements are common to both. Apple’s Health app covers most of the bases when it comes to tracking your essential fitness and activity indicators - nutrition, sleep, physical exercise, but Apple has gone further with HealthKit, which allows health and fitness apps downloaded from the App Store to share data with each other. Apple has committed to Watch, and its attention to practical and eye-pleasing design as well as useful tracking features is commendable. ($529)

Outside of the Fossil Group, we're waiting for the Casio Pro Trek WSD-F30 and Montblanc Summit 2. The Summit 2 will be the first smartwatch to run on Qualcomm's new Snapdragon 3100 processor, which aims to make a raft of improvements including beefing up the battery life. It's also expected to be joined by a new Louis Vuitton smartwatch, which will run on that new Snapdragon chip.

Basically, smartwatches are wearable-technology devices that maintain a relatively persistent wireless connection to your mobile device—usually a smart phone—and can receive notifications of incoming calls, texts, instant messages, social-network updates, and more, from that device. Some can also let you accept and conduct phone calls right on the watch. And even newer models (the Samsung Gear S, for one) can act as smart phones all on their own, without needing a paired phone nearby.
Our top pick for most people is the Apple Watch Series 4 with GPS (starting at $399), which has a huge display, ultra-fast processor, Raise to Speak Siri, fall detection and a built-in electrical heart rate sensor for taking on-the-go electrocardiograms. It also runs watchOS 5, which makes the watch even more useful with automatic workout-tracking, offline podcast playback and a Walkie-Talkie voice chat feature.
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