TY - JOUR TI - Decreasing human body temperature in the United States since the Industrial Revolution AU - Protsiv, Myroslava AU - Ley, Catherine AU - Lankester, Joanna AU - Hastie, Trevor AU - Parsonnet, Julie A2 - Jit, Mark A2 - Franco, Eduardo A2 - Waalen, Jill A2 - Rühli, Frank VL - 9 PY - 2020 DA - 2020/01/07 SP - e49555 C1 - eLife 2020;9:e49555 DO - 10.7554/eLife.49555 UR - https://doi.org/10.7554/eLife.49555 AB - In the US, the normal, oral temperature of adults is, on average, lower than the canonical 37°C established in the 19th century. We postulated that body temperature has decreased over time. Using measurements from three cohorts—the Union Army Veterans of the Civil War (N = 23,710; measurement years 1860–1940), the National Health and Nutrition Examination Survey I (N = 15,301; 1971–1975), and the Stanford Translational Research Integrated Database Environment (N = 150,280; 2007–2017)—we determined that mean body temperature in men and women, after adjusting for age, height, weight and, in some models date and time of day, has decreased monotonically by 0.03°C per birth decade. A similar decline within the Union Army cohort as between cohorts, makes measurement error an unlikely explanation. This substantive and continuing shift in body temperature—a marker for metabolic rate—provides a framework for understanding changes in human health and longevity over 157 years. KW - human body temperature KW - resting metabolic rate KW - historical trends KW - cohort studies JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -