Abstract
Recently, promotion of physical fitness is growing up, and creation of simple indicators that can assess fitness condition is desired. Onset of blood lactate accumulation (OBLA) defined as a point at which blood lactate concentration (BLC) reaches 4[mmol/L] during physical load has been used for index of physical fitness. However, it requires cumbersome blood sampling and, therefore, has not been applicable to continuous monitoring. To overcome these drawbacks, we proposed a new method for estimating physical fitness using a non-invasively obtained cardiovascular variables. 27 male and 19 female healthy adults were involved and their heart rate (HR), stroke volume (SV) and cardiac output (CO) were non-invasively measured during ergometer exercise using an impedance cardiograph (PhysioFlow, NeuMeDx). BLC was also measured using a BLC monitor (LactatePro2, Arkray). From the results, it was confirmed that the values of work load at the inflection point of CO were coincide well with those of OBLA, suggesting superiority of CO in estimating physical fitness rather than HR nor SV. These results could be explained that HR and SV reflect myocardial chronotropic and inotropic condition, respectively, on the other hand, CO reflects both.
