SICONOLFI, STEVEN F., EILEEN M. CULLINANE, RICHARD A. CARLETON, and PAUL D. THOMPSON. Assessing JOURNAL/mespex/04.02/00005768-198205000-00014/ENTITY_OV0312/v/2017-07-20T222045Z/r/image-pngo2max in epidemiologic studies: modification of the Åstrand Rhyming test. Med. Sci. Sports Exercise, Vol. 14, No. 5, pp. 335–338, 1982. Direct measurement of maximum oxygen uptake (JOURNAL/mespex/04.02/00005768-198205000-00014/ENTITY_OV0312/v/2017-07-20T222045Z/r/image-pngo2max) is he standard index of cardiorespiratory fitness, but is practical only in a laboratory setting. Current cycle ergometer tests to estimate JOURNAL/mespex/04.02/00005768-198205000-00014/ENTITY_OV0312/v/2017-07-20T222045Z/r/image-pngO2max are difficult for inactive adults because most of these tests are lengthy and require a high initial exercise rate. We modified an existing test, the Åstrand-Ryhming test, to avoid these problems. Maximum oxygen uptake was measured directly and estimated by means of our protocol in a test group of 50 men and women, ten for each decade between 20 and 70 yr, to develop multiple regression equations to correct for variations due to age. Equations for each sex were computed with directly measured JOURNAL/mespex/04.02/00005768-198205000-00014/ENTITY_OV0312/v/2017-07-20T222045Z/r/image-pngO2max as the dependent variable and with the estimated JOURNAL/mespex/04.02/00005768-198205000-00014/ENTITY_OV0312/v/2017-07-20T222045Z/r/image-pngO2max and age as independent variables. The validity of these equations was tested by deriving data from an additional 63 subjects (validity group). No significant differences were found between the directly measured JOURNAL/mespex/04.02/00005768-198205000-00014/ENTITY_OV0312/v/2017-07-20T222045Z/r/image-pngO2max he JOURNAL/mespex/04.02/00005768-198205000-00014/ENTITY_OV0312/v/2017-07-20T222045Z/r/image-pngO2max estimated by our protocol and equations. For each group, the mean difference between the two values was less than 120 ml·min-1. Correlations between the measured and estimated JOURNAL/mespex/04.02/00005768-198205000-00014/ENTITY_OV0312/v/2017-07-20T222045Z/r/image-pngO2max, ranged from 0.92–0.93 for the age groups. Our modification of the Åstrand-Ryhming protocol accurately estimates JOURNAL/mespex/04.02/00005768-198205000-00014/ENTITY_OV0312/v/2017-07-20T222045Z/r/image-pngo2max and is safe and suitable for assessing cardiovascular fitness in epidemiologic studies of people between the ages of 20–70 yr.