I have tried resetting the AirPods once I was back at my house -- it worked fine until 5 minutes after I started my next walk. Poof! The sound stops immediately and in a few seconds I'll heard the disconnect ba-doom. I always leave the Airpod case at home while I go walking, so I've never tried resetting while I'm out walking. However, I have disconnected and re-connected while I'm walking and it always works in only the left ear. If you think it will help, I'll take the case with me but I am skeptical.
I don't think I mentioned that I am using the AirPods to play music saved on my phone, so I'm not streaming via WiFi or cellular service, so I don't see how the problem could be caused by interference. The phone is in my pocket and the Airpods are on my feet (just kidding), so they aren't more than a couple of feet apart. Last week, about an hour after my walk and my Airpods disconnecting, I put them on in the house and both Airpods worked immediately with no static and no interruptions. I was able to use them for almost two hours before the battery in the left ear wore out.
At first, I thought the issue might be cold or static electricity caused by nylon windpants, but I have read where it shouldn't be a problem unless it's below freezing. Do either of those things strike a cord with someone?