The latest research suggested that the normal human body temperature has dropped over time. The recent analysis of temperature trends suggested that since the 19th century the normal human body temperature has dropped due to physiological changes. The researchers highlighted the potential reasons behind these alterations.
The complete findings of this study are published in the journal “eLife.”
Majority of people only check our temperature when we suspect having a fever because of cold or due to any infection but body temperature can be influenced by several other factors which include lifestyle habits, age, and the environment or climate can also influence our body temperature and dispersion of heat from the body.
Body temperature is a marker of metabolic health. The researchers explained in this new study that the temperature of the human body indicates the metabolic rate which is somehow linked with the longevity and size of the body.
A German physician, Carl Reinhold August Wunderlich surveyed almost 25,000 people in a city in 1851 and concluded that the standard human body temperature is 37°C.
However, the recent surveys and analyses suggest that now the average body temperature is now lower.
A study of above 350.000 individuals in the United Kingdom and nearly about 250,000 temperature measurements found that 36.6°C is now the normal average temperature. Many questions arise related to this change like do these new findings reflect increased life expectancy and better health? Or could this cause the changes in temperature measurement tools?
The researchers hypothesized that the temperature differences observed between the 19th century and till date are real and this change provides the physiological clues to changes in human health and longevity since the Industrial Revolution.
To test this hypothesis, the scientists analyzed information from three different datasets:
- The first dataset was obtained from the Union Army veterans from 1862-1930.
- The second set included data from the United States National Health and Nutrition Examination Survey I, from 1971 to 1975.
- The third data set included data from the Standard Translational Research Integrated Database Environment containing data of people who received healthcare through Stanford from 2007 to 2017.
The scientists overall accessed 677,423 temperature measurements which were integrated by them and form a model of change with time.
The findings include:
- The average today men body temperature is 0.59°C lower than that of those born in the early 19th century.
- Similarly, the body temperature of women is dropped by 0.32°C from the 1890s to the recent date.
- Overall the study analysis found a decrease of 0.03°C in the average body temperature with each decade.
Dr. Parsonnet said that we are now physiologically different from what we were in the past. The environment has changed, the temperature of homes has changes, interaction with microbes and the food trend has changed. All these factors contribute to this change. As a human, we think we all are monomorphic but we are not because we are actually physiologically changing.
Dr. Parsonnet believes that our average metabolic rate (energy consumed by the body) has also declined with time and this decline might result from the decrease in the inflammation as inflammation produce different cytokines and proteins which raise body temperature.
Finally, heating and air conditioning have resulted in a consistent body temperature making is useless to expend energy for maintaining the human body temperature.