With the arrival of Apple Watch Series 4 and Google's redesigned Wear OS platform, this is a great year to give the gift of smartwatches. If money is no object, Apple's latest-generation wearable ($399 and up) is a good all-around choice for anyone in your life who carries an iPhone. It has a bigger screen than its predecessors, longer battery life and expanded heart-rate monitoring features that let the wearer know if their BPM is too high or too low. You might also consider Samsung's similarly priced Galaxy Watch instead of the Series 4 if you're buying for an Android user (especially consummate Samsung fans).
That said, Fossil's Q Venture HR is a decent Wear OS alternative to the Galaxy Watch, with heart rate tracking and NFC connectivity. It could be as much as $100 cheaper, too, depending on the model you choose. Yet another option is Withing's Steel HR Sport -- it's not quite as smart as its rivals, but it makes up for the lack of high-tech touches with a timeless design and some solid fitness tracking features.
Finally, if you're shopping for someone who's floated the idea of a Fitbit (or something like it), the brand's Versa smartwatch could be a great choice. It looks like a slightly wider Apple Watch with a battery rated for days of usage. Sure, it lacks GPS and NFC, but it comes with a number of health-related tracking features, including one that can monitor a woman's menstrual cycle.