BackgroundBody temperature (BT) is thought to have associations with oxygen consumption (VO2). However, there have been few studies in which the association between systemic VO2and BT in humans was investigated in a wide range of BTs. The aims of this study were 1) to determine the association between VO2and age and 2) to determine the association between VO2and BT.MethodsThis study was a retrospective study of patients who underwent surgery under general anesthesia at a tertiary teaching hospital. VO2was measured by the Dräger Perseus A500 anesthesia workstation (Dräger Medical, Lubeck, Germany). The associations of VO2with age and BT were examined using spline regression and multivariable regression analysis with a random effect.ResultsA total of 7,567 cases were included in this study. A linear spline with one knot shows that VO2was reduced by 2.1 ml/kg/min with one year of age (p< 0.001) among patients less than 18 years of age and that there was no significant change in VO2among patients 18 years of age or older (estimate: 0.014 ml/kg/min, p = 0.08). VO2in all bands of BT < 36.0 °C was not significantly different from VO2in BT >  = 36 °C and < 36.5 °C. Multivariable linear regression analysis showed that compared with VO2in BT >  = 36 °C and < 36.5 °C as a reference, VO2levels were significantly higher by 0.57 ml/kg/min in BT >  = 36.5 °C and < 37 °C (p< 0.001), by 1.8 ml/kg/min in BT >  = 37 °C and < 37.5 °C (p< 0.001), by 3.6 ml/kg/min in BT >  = 37.5 °C and < 38 °C (p< 0.001), by 4.9 ml/kg/min in BT >  = 38 °C and < 38.5 °C (p< 0.001), and by 5.7 ml/kg/min in BT >  = 38.5 °C (p< 0.001). The associations between VO2and BT were significantly different among categorized age groups (p= 0.03).ConclusionsVO2increases in parallel with increase in body temperature in a hyperthermic state but remains constant in a hypothermic state. Neonates and infants, who have high VO2, may have a large systemic organ response in VO2to change in BT.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12871-023-02182-1.