Apple says the new Apple Watch Series 4 has been "fundamentally redesigned and re-engineered to help you stay even more active, healthy, and connected." I've spent about a week with my Apple Watch Series 4 and my new iPhone XS Max. Here's what I've learned.

Apple Health

Due to Apple's commitment to helping you maintain your health and wellness, the Apple Watch Series 4 now has a raison d'être. When coupled with the Apple Health App (included with iOS), the Series 4 goes way beyond the concept of fitness tracker or step counter and enters the realm of purpose-built health/medical/research monitor. Apple's health and wellness strategy clearly differentiates the Apple Watch (and companion iPhone) from all other devices or combinations of would-be-competitive hardware and software.

New features include a second-generation optical heart sensor which allows the Health app to provide comprehensive heart rate monitoring (it even looks for irregularities like atrial fibrillation). And, coming soon, an ECG app that will generate a 2-lead (one electrode in the watch's crown, and the other on the back crystal) electrocardiogram you can share with your doctor.

There are several other sensors in the Series 4 including a new and improved gyroscope as well as a new and improved accelerometer which can sense up to 32 g-forces (the Series 3 can only sense up to 16 g-forces). When combined with included software, these sensors know if you fall, know how hard you fell, and ping you to respond that you're OK. If you don't respond, the device will call emergency services. The company does have a clear disclaimer in the Fall Detection section of the Watch App that says, "Apple Watch cannot detect all falls."

I have been using the Apple Watch/iPhone combo with Apple Health for a while now and have compiled a fair amount of useful data. I am currently writing some software to help transform raw Apple Health data into actionable insights. I'll keep you posted.

It's bigger and thinner!

The display on the Series 4 is 30 percent larger, but the overall dimensions of the watch are 30 percent smaller. So, buy the 44mm (if your wrist is big enough), because WatchOS icons are much easier to deal with on the bigger device.

Apple Watch Series 3 small case – 38 mm — 563 sq mm display area
Apple Watch Series 4 small case – 40 mm — 759 sq mm display area
Apple Watch Series 3 large case – 42 mm — 740 sq mm display area
Apple Watch Series 4 large case – 44 mm — 977 sq mm display area

Apple Watch Series 3 – 11.4mm thick
Apple Watch Series 4 – 10.7mm thick

Geeky stuff

The 64-bit dual-core S4 processor is up to twice as fast as the Series 3's dual-core S3 processor, and you will notice the difference. The speaker is 50 percent louder, so you can hear a call on city streets. The crown has sensors in it and provides haptic feedback. The Series 4 features a W3 wireless chip (Series 3 had a W2 wireless chip) which helps with wireless connectivity. Even its Bluetooth was upgraded from 4.2 to 5.0.

I am happy to report that Apple's claims of longer battery life are only slightly exaggerated. Our friends in Cupertino say, "18 hours on a single charge." Um … no, but battery charge on the Series 4 is noticeably better than it is on the Series 3. Last, but not least, the Series 4 features LTPO, a new display technology designed to improve the aforementioned power efficiency and battery life.

My fashionista friends are happy that aside from silver and space black, the Series 4 is available in gold.

What hasn't changed

The Apple Watch Series 4 also includes features you have come to know and love from previous iterations. It's water resistant up to 50 meters; has a barometric altimeter; has a nice array of satellite navigation tools (GPS, GLONASS, Galileo, and QZSS), and comes with 16GB of storage capacity.

Variations on a theme

There are a couple of other flavors of Apple Watch Series 4 that are noteworthy. Apple Watch Nike+ (available 10/5) includes the Nike Run Club and Nike Training Club apps for both runners and overall workout enthusiasts: "Together they'll help you build the endurance and strength to take your fitness to the next level." And Apple Watch Hermès, which lets you spend even more money on an Apple Watch, under the guise of tech and fashion. Varieties include Double Tour, Single Tour, Single Tour Rallye, and Single Tour Deployment Buckle.

Should you get one?

If you are into health, wellness, fitness, and heart health, or if you're training for anything, this is the watch for you. If your use case is aligned with Apple's health and wellness strategy, don't hesitate. We're just at the beginning of Apple's healthcare mission, and I am really impressed with their progress so far.

However, if you are just interested in seeing your notifications on your wrist, there are many other smartwatches that integrate text, email, notifications, and phone calls.

The lowest-priced Apple Watch is $399, but the sky is the limit (watch bands start at $49, but have no upper price boundary). That said, the Apple Watch Series 4 is awesome.

Author's note: This is not a sponsored post. I am the author of this article and it expresses my own opinions. I am not, nor is my company, receiving compensation for it.