Vital capacity does not increase with age. According to the New Health Guide, vital capacity decreases with age. According to Clinical Interventions in Aging, lower vital capacity is the result of age-related decrease in residual capacity and residual volume.
Vital capacity refers to the maximum amount of air an individual can expel after inhaling fully. The New Health Guide states that the average vital capacity of an adult is from 3 to 5 liters. The exact vital capacity depends on the individuals' ethnicity, age, height, weight and sex. It is also affected by underlying respiratory diseases and lifestyle factors such as smoking. Vital capacity can be improved through exercise, which can help to slow down the age-related decrease of vital capacity.