Rubbish theory

I derived a strange theory on a certain monotonous trip on a coach. When the coach climbs to high altitude, the shampoo bottles bloated due to the low atmospheric pressure acting on the contents of the bottle. When I open the bottle in the hotel's bathroom, the shampoo puked out in a sudden burst.

Applying the same theory to the human body, we should experience severe farting and at least one session of good burst while passing motion.

On the way down, the pressure cells acting on the bottle is higher, hence, the soap bottle will be dented. The same pressure is applied on the human body and one travelling downhill will experience tightness physically, explaining for the queasiness.