The assertion that 98.6F is the normal body temperature was based on research done in 1851.
A new study indicates that:
- Average body temperatures have decreased by a little more than 1 degree between 1851 and 2020;
- That body temperature readings are affected by age, gender, body mass, and time of day. Thus “normal temperature” is a range, not a number.
A decline in the rate of metabolism is probably the cause of a decline in body temperature. This in turn could be the result of reduces rates of inflamation and better or more consistent home heating.
- Myroslava Protsiv, Catherine Ley, Joanna Lankester, Trevor Hastie, Julie Parsonnet. Decreasing human body temperature in the United States since the industrial revolution. eLife, 2020; 9 DOI: 10.7554/eLife.49555
- Stanford Medicine. “Human body temperature has decreased in the United States.” ScienceDaily. ScienceDaily, 8 January 2020. <www.sciencedaily.com/releases/2020/01/200108090328.htm>