Question

If vital capacity was reduced, but tidal volume remained the same for an individual, how would it affect them? Would they notice at rest? If not, why not, and when might they notice the VC reduction?

Answer 1

Decreased vital Capacity is seen in any obstructive disease of the lung e.g. Asthma, bronchectiasis, COPD, emphysema. If tidal remains unaffected person will have normal breathing at rest but will have difficulty during forceful exhalation or increasing tidal volume.

No, at rest such patient will not be noticed, as they will have normal breathing.(as tidal volume is normal)

They will turn symptomatic during any activity which needs to increase tidal volume like exercise, running etc.