Greetings Ceedeedee,
It sounds as though you're using your iPhone to track your steps, distance, and speed when on a run, but you're not seeing the speed being calculated properly. Just to confirm, you're not using an Apple watch and tracking the running via the Workout and Activity apps? If not, and you're only using the Health app on the iPhone we would want to troubleshoot the app itself. To troubleshoot and resolve app related issues, you'll want to complete the steps listed below.
- Force the app to close, then reopen the app to see if the issue persists.
- Restart your iPhone. After the iPhone powers back on, reopen the app to see if the distance changes.
You can also find these steps outlined in the following article.
If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open
Have a great rest of your weekend!