Chris Boardman with tissue up his nose ....?

Question

watching highlights of some tour de france classic stages - and on boardman's time trial warm up he rode on his exercise bike with tissue up his nose, which obviously blocks him from breathing through his nose

in a more technical way - why did he warm up with the blocked nose and what are the advantages from it?

Answer 1

It's loaded with Menthol Mate. - True!

EDIT: Why the thumbs down??? Please can the uninformed culprit explain themselves????

I repeat - The wads are impregnated with Menthol.

.

Answer 2

It helped him train for the high altitudes when they reached the mountain areas.