Cardio Fitness data

I get no Cardio Fitness data from my Series 8 apple watch. It does not even show up in the heath app as a data source for cardio fitness data. It does show for every other kind of data. I have tried all of the tips listed here and still nothing. I have even pun paired and re-paired it to my phone several times. I have had the watch for months and I do 2-5 mile walks/runs with heart rates as high as 150 and duration as long as 45 minutes. Still nothing.

As a 65 year old with a newly installed heart stent this is the most important data I need. I asked Geek Squad and they could not help me either.

Can someone at Apple please help me resolve this. I spent a lot of money on this watch to get this specific data. Everything else works great.

Thank you