In the nearly two centuries since German physician Carl Wunderlich established 98.6℉ as the standard“normal” body temperature, it has been used by parents and doctors alike as the measure by which fevers and often the severity of illness have been assessed.
In more recent years, however, lower body temperatures have been widely reported in healthy adults. A 2019study showed that the normal body temperature in Americans is about 97.5℉. A multinational team led by Michael Gurven and Thomas Kraft have found a similar decrease among the Tsimane, a native population in the Bolivian Amazon.
A key question, then, is why body temperatures have declined over time both for Americans and Tsimane. Extensive data available from the team’s long-term research in Bolivia addresses some possibilities.
Declines might be due to the rise of modern healthcare and lower rates of lingering mild infections now as compared to the past. But while health has generally improved over the past two decades, infections are still widespread in rural Bolivia. Therefore the results suggest that reduced infection alone can’t explain the observed body temperature declines.
It could be that people are in better condition, so their bodies might be working less to fight infection. Or greater access to antibiotics(抗生素) and other treatments means the duration of infection is shorter now than in the past.
Another possibility is that our bodies don’t have to work as hard to regulate(调节) internal temperature because of air conditioning in the summer and heating in the winter. While Tsimane body temperatures do change with time of year and weather patterns, the Tsimane still do not use any advanced technology for helping to regulate their body temperature. They do, however, have more access to clothes and blankets.
The researchers were initially surprised to find no single “magic bullet” that could explain the decline in body temperature. It’s likely a combination of factors—all pointing to improved conditions.
8. What role has 98.6℉ been playing?
A.It can show an illness is incurable. |
B.It can help doctors determine a fever. |
C.It can arouse people’s attention to health. |
D.It can indicate an abnormal body temperature. |
9. Why rural Bolivia is mentioned in the text?
A.To arouse readers’ sympathy. | B.To imply other existing factors. |
C.To call for improved medical access. | D.To discuss methods to reduce infections. |
10. What contributes to the decline in body temperature?
A.The growing adaptability. | B.The international policies. |
C.The improved conditions. | D.The worsening environment. |
11. What’s the main idea of the passage?
A.Modern life improves the general health. |
B.Living conditions greatly affect mankind. |
C.The normal body temperature is declining. |
D.Various factors influence the body temperature. |