... it has apps on it such as Strava but I personally find these to simple and don't offer the features I like (e.g., when running I want to be told when I have run a kilometre and then I can quickly check my time on the watch).
You could try POLARBEAT. I don't use it on a smartwatch, but I use it to report to my iPhone on the handlebars, and the iPhone loudly announces every kilometer that my average speed was x kph or x miles per hour or even, probably more useful to a runner, x minutes per kilometer. It also announces average heart rate for that distance or time. You can switch these facilities in and out, of course. The POLARBEAT software works well with Polar's proprietary H7 belt (I had to have the belt replaced under warranty, which was a nuisance, and it is the priciest belt I own by at least three multiples) and the iPhone, but I found the combo doesn't play so nicely with other Bluetooth-capable belts. My iPhone is the long-obsolete 4S, chosen because then and now it has the biggest battery in the sturdier (all-ali-cased) versions of the Apple. However, battery life is still miserable. I carry a booster battery in the same dry bag on the handlebar as the iPhone and plug it in when I start riding. Without the booster, your day in the saddle had better not be longer than 6 hours, which leaves a bit of leeway for getting lost on your way to a plug. With the Blitzwolf booster, about an inch square and as long as the iPhone, that I now use I could probably go two full days, but that's without switching on the GPS: in fact, everything except Bluetooth and the phone itself is switched off to conserve power. Frankly I don't see how even my setup can be any kind of a long distance touring option. I manage on short local tours but I stay in a guest house every night, and my touring day generally keeps Irish time, which means that rain cuts it short sooner rather than later. So on a short tour, I'm never closer to a dead phone than the phone with 100% charge in it and another day's reserve in the Blitzwolf. In addition the battery for the electric motor on one of my bikes has a USB port and I could run the phone off that, but, except for testing that it works, I never have because it is a nuisance and the cables are aesthetically unpleasing. In fact there is a another smidgin of reserve as, though I operate the lamps day and night off the dynamo as DRL, there's generally something left to operate a charge system I built to recharge the iPhone but never even tried on the iPhone (it's irreplaceable, so I don't want to blow it up), instead using the Blitzwolf as my buffer; that's good on a day with plenty of downhills for another hour or so on the phone, but the little board sheltering under its own heatsink of a piece of angle iron is ugly, and I in fact have plenty of reserve, so I just mention the possibility.
***
I looked into smart watches a couple of years ago, but decided against them for not being smart enough -- none have enough battery power to report even my heart rate continuously, never mind blood pressure) -- and all of them suffer from insulting battery capacities for other functions such as GPS. I concluded that they're toys and gimmicks, though I expect them to grow up in the next few years. Currently they seem to me to be aimed at what you use yours for, reporting on a daily run, a couple of hours at most. The H7 belt coupled with an iPhone bypasses this difficulty by using the phone's power...clumsy, sure, but a lot more secure, I think.
Still, one day soon we'll all be talking into our thumbs and wondering why we ever carried around so much clunky communications gear.
