They measured my lung capacity. 

You put your mouth around a cardboard tube and exhale as hard as you can. 

You may have done this, definitely if you’re asthmatic ( as I am sometimes )

‘Normal’ is 5 to 6 litres of air. Mine was previously 5.75 litres. 

Now, as a result of a good rib and lung battering, no exercise,  or pushing myself aerobically,  it’s a tiny 1.6 litres

That’s less than the cat, I reckon. 

That means that any form of aerobic exercise will be bloody hard at the moment!

Very sobering! I’ve been taking VERY deep breaths ever since to try to stretch my lungs!