Xiaomi - Mi Smart Band 5

I used to wear MiBand5 (xiaomi) for this purpose for 4 years. Got it for about usd25. App zepplife sync well with my iphone n strava. Latest is xiaomi smartband 9 active. Price about the same. These watches dont have gps function. start a running session thru the app and the watch will automatically enter running mode that will enable heart rate monitoring, step counts etc during the session. The screen is too small to see clearly your current heart rate while running, but i just glance at my iphone screen to see parameters such as heart rate, pace, distance, time workout. I use iphone 12 mini so the size is comfortable enough to hold in my hand while running. i attached a strap to the iphone casing for more secure hold of it.

Do you want to just measure distance and track your route and heartbeat? If so the cheeapest is to get a smart band (i have the MI smart band). I can't remember the price but it's definitely less than 100, but obviously will not have as many things as a sport watch like the others suggested. It can also be a good idea to get something cheap and if in a couple years you still use you can save for something better

I've used "Mi Bands" (Xiaomi Smart Band) for the longest time, fundamentally for Step Counting and Sleep Tracking, rarely as a bluetooth remote control and for NFC payment. It's very small and unintrusive, doesn't bother you at all and it only needs charging every two-three weeks. You don't have to use all the unneccesary bells and whistles obviously.

I tried the MiBand. I found it very inaccurate so I ended up not using it