Milzy
Guru
100ml is a very small difference. And cycling won't increase your lung capacity much. To increase it, best idea is to do physical activities that require you to control your breathing - swimming is a great example.
I did a huge bbq the day before with a lot of smoke. Also end of cold won’t have helped. There’s pollen, irritants in the air etc. It would be nice if asthmatics and welders got free chest scans to make sure though.