Maximal oxygen uptake (VO₂max) is an important determinant of health-related physical fitness. In 2006, the Japan Ministry of Health officially announced a reference value and reference interval of VO₂max. However, the values were established on the basis of a systematic review of reports published in the Western countries and was not based on the VO₂max data of the Japanese population. Therefore, we conducted a study entitled “The study on a minimum zone of VO₂max as one of the determinants of health-related physical fitness in Japan” from 2004 to 2006 as a project of the Japanese Society of Physical Fitness and Sports Medicine (JSPFSM). In addition, we collected the already published VO₂max data of the Japanese population from the JSPFSM website. In the present study, we attempted to determine the reference interval of VO₂max with regard to age, gender, and different methods of exercise. Further, we established a cutoff value of VO₂max for determining metabolic syndrome (MS).
1. Reference interval of maximal oxygen uptake (VO₂max)
For treadmill exercise, 325 and 364 values and for cycle ergometer exercise, 1175 and 2178 values were collected for men and women, respectively. There was balanced distribution of VO₂max with regard to age among the laboratories which provided data to the present project. The collected data that satisfied the VO₂max criterion were adopted for the analysis. These data were regressed to age on gender and methods of exercise. The percentage of VO₂max was calculated using the following equation: %VO₂max = measured VO₂max×100/age-estimated VO₂max. Iterative truncation method was used to calculate the reference interval of VO₂max (70%~130% ・VO₂max) from the crude data of %VO₂max, and converted to VO₂max. Thus, the reference interval of VO₂max for healthy Japanese was determined with regard to age, gender, and different methods of exercise.
2. Cutoff value of VO₂max for determining metabolic syndrome (MS)
Using the VO₂max data of subjects with body mass index (BMI) of≧25 and with≧2 MS risk factors and that of subjects with normal BMI and no risk factors, we calculated the sensitivity and specificity. The cutoff value was determined using the receiver operating characteristic curve (ROC). This cutoff value was defined as the critical value of VO₂max for avoiding MS and maintaining healthy conditions.

DESCENTE SPORTS SCIENCE Vol.30/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE