Good afternoon chrissmith60,
Welcome to the Apple Support Communities!
I understand you are having some issues with your iPhone XS when running. What do you mean by disable? Do you mean your iPhone goes to sleep? Have you tried changing your Auto-Lock settings so that the iPhone does not go to sleep during your run? (Settings > Display & Brightness > Auto-Lock). Try changing this setting to "Never" before going on your next run. For the rest of the day, you can change the setting back if you wish, but I'm in the habit now of just pressing the Side button manually to put the iPhone to sleep when I'm not using it.
Wake and unlock iPhone - iPhone User Guide - iOS 13
It sounds like some dampness and condensation may be happening in the waterproof holder under your running jacket. Have you tested this by putting the iPhone in a different location or pocket, or in an arm band or waist belt?
Please reply to this thread if the issue persists after trying the steps above, and I'll do my best to help you with this!
Take care.