According to this article, human body temperatures may be undergoing global cooling while our planet warms up! Studies seem to indicate a downward trend in average body temperature of 0.03 C per decade -- about a degree F over the past 150 years. While small, this trend can be clinically significant, since it may mean that the range at which we decide a person has a fever may need to be changed downward.
What could be causing this trend? The authors of the study wonder if the incidence of inflammatory conditions has decreased. Since it is also clear that body weights and BMI have had a significant upward trend over the past century, I have another suggestion, based on the study from 1989 below: the effect is due to the increase in overweight and obese contingents of the overall population. At least some things about that are kind of cool.
ABSTRACT
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Eur J Appl Physiol Occup Physiol. 1989;58(5):471-5.
Human body temperature is inversely correlated with body mass.
Adam K.
Abstract
Forty-two women and 18 men of mean age 54 years had their sub-lingual oral temperature measured hourly from 0700 h to 2300 h. Mean oral temperature (averaged over the 17 readings) was inversely correlated with body mass in the group as a whole (r = -0.44, df = 58, p = 0.0003). The women had significantly higher mean oral temperatures than the men, but the inverse relationship between mean oral temperature and body mass was still significant when the data from the women were analyzed separately (r = -0.37, df = 40, p = 0.013). The results suggest that in humans, mean body temperature is inversely related to body mass, irrespective of gender.
PMID: 2759072 DOI: 10.1007/bf02330699
