Hi there, @Deano74. That's very unusual that your Samsung Health app is crashing after a recent update. It's not clear to me whether you installed a software update on your S20, or updated the app itself. I understand that uninstalling and reinstalling the app hasn't resolved this, so we can look at other possibilities.
In any case, the tips provided in the article below should help you get the Samsung Health app working as expected again:
Please update the thread and let us know what helped you resolve this, and definitely let us know if the issue persists.