Recent research suggests a shift in what is considered a normal body temperature, indicating a decrease in average temperatures over time. This change calls into question the long-held standard of 37°C (98.6°F) as the typical human body temperature.
In a study, the average temperature of 96 adults over two weeks varied from 35.2°C (95.4°F) to 37.4°C (99.3F), highlighting the importance of knowing your own average temperature when healthy, rather than relying on a universal standard. It appears that an average oral temperature of 97.5°F has been observed in analyses of 20 studies conducted between 1935 and 1999. Similar findings were reported in a 2023 study and an earlier study involving more than 35,000 people, with the average body temperature estimated at 97.9°F.
Stanford researchers have found that the average human body temperature in the United States has decreased since the 1800s, which may be due to improved health and living conditions reducing inflammation. This decline suggests that today’s normal body temperature is closer to 97.9°F.
Body temperature typically rises in the afternoon compared to morning levels. A fever is identified when body temperature exceeds 100.4°F (38°C). Different levels of fever severity exist, with a low-grade fever ranging from 99.1°F to 100.4°F (37.3°C to 38.0°C).
Maintaining internal body temperature around 98.6°F, give or take a few degrees, is crucial for optimal body function. However, an average body temperature drop in the U.S. has been noted, now averaging around 97.9°F.
A body temperature hovering around 96°F or 97°F might be normal for some, but it could also indicate conditions such as hypothyroidism, diabetes, liver or kidney failure, infection, endocrine dysfunction, or the effects of certain medications, alcohol, or drug use.
Abnormal body temperature may signify fever (high temperature) or hypothermia (low temperature). Fever is indicated when body temperature is about 1 degree or more above the normal 98.6°F, while hypothermia is defined as a drop in body temperature below 95°F.
For further information, please refer to the sources below:
Harvard Health
Harvard Health
Stanford Medicine
Harvard Health
Center for Healthy Aging
Stanford Medicine
Go Ask Alice!
University of Rochester Medical Center
