when i came down with "covid" february 2-5 2020 i discovered very quickly i had to stay very still and consciously slow my breathing
the cough made pain in my intercostal muscles around the ribs almost within half an hour, it was an unprecedented fatigue onset for a cough, i think i got up a few times in that 3 days to go to the toilet and drink water but it was mostly a case of "meditate yourself to sleep, this will pass"
nastiest flu type illness i have ever experienced in my life, and i can see how it could be deadly to someone with several of the conditions i have. good thing i've moved right the hell away from the population!