On Wednesday, I went to our local hospital for an echocardiogram. They stuck sound transducers to my back, put jelly on my front, and took a whole bunch of readings. The process was entirely painless, except when they took the transducers off - ouch! That's the drawback of being a bit hairy.
Also - my ankle, which was a little bit umpty after using the treadmill, now feels better. What I'm going to do, is use walking boots on the treadmill next time, because they give some ankle support. And that worked!
Also what worked, it watching Netflix while I walk or bike. I don't have to be aware of road traffic :-).
So I added another wifi access point near where the treadmill and bike are, so I get good connectivity.