Multiscale modeling of respiration

A multiscale mathematical model was developed to distinguish responses of external and cellular respiration to exercise of moderate intensity. The simulation shows that the characteristic MRTs of external and cellular respiration are similar even when a transit delay exists between the tissue cells and the lungs. The results of our model show that the O₂ transport processes from lungs to muscle are tightly coupled to provide sufficient O₂ for working skeletal muscle during exercise in normal subjects. Under abnormal conditions, the effect of O₂ transport limitation, occurring at a different scale of the body, on internal and external respiration can be examined. Such results can be used for comparative quantitative analysis of the regulation of respiration in subjects suffering from abnormal function associated with disease states (for example, chronic obstructive pulmonary disease, diabetes, and congenital heart disease).