05 - Humans are getting colder

Carl Wunderlich's seminal 1868 work "The Course of Temperature in Disease" defined the average human body temperature as 37 degrees celsius, a number that is still frequently quoted today. But the question of the average body temperature is far from settled. Could it be that it is changing with time?

Music:
Variatio 3 a 1 Clav. Canone all Unisuono
Music by JS Bach, played by Kimiko Ishizaka for the Open Goldberg Variations project

References:
Ley C et al 2023 “Defining usual oral temperature ranges in outpatients using an unsupervised learning algorithm” JAMA https://doi.org/10.1001/jamainternmed.2023.4291

Mackowiak, P & Woden, G 1994 “Carl Reinhold August Wunderlich and the Evolution of Clinical Thermometry” Clinical Infectious Diseases https://www.jstor.org/stable/4457716

Protsiv M et al 2020 “Decreasing human body temperature in the United States since the Industrial Revolution” eLife https://doi.org/10.7554/eLife.49555

Speakman et al JR 2023 “Total daily energy expenditure has declined over the last 3 decades due to declining basal expenditure not reduced activity expenditure” Nature Metabolism https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10445668/

Sund-Levander et al 2002 “Normal oral, rectal, tympanic and axillary body temperature in adult men and women: a systematic literature review” Scandinavian Journal of Caring Sciences https://doi.org/10.1046/j.1471-6712.2002.00069.x

Wikipedia “Doubly labeled water” https://en.wikipedia.org/wiki/Doubly_labeled_water

Wikipedia “Medical Thermometer” https://en.wikipedia.org/wiki/Medical_thermometer