If I'm one of those at risk people, my "active" activities are going to lean to the safer options I can find like walking or jogging. No mountain climbing, kayaking, skiing, and so forth.
I explained this to my parents who have a few existing health conditions that have a high correlation with COVID mortality rates based on the data I've seen. They don't need to go into the hospital for a cut or injured finger if they can avoid the accident in the first place. Obviously if a real emergency arrives you need to weigh the risks of contracting COVID vs the emergency (an admittedly nearly impossible task) but you should try to minimize risks for the time being where you can to try and avoid that situation completely.
Basically you need to be a little more risk averse than you may normally be under the assumption a minor injury is manageable if you're potentially susceptible to COVID right now.