More than what the thermometer reveals

If you run a body temperature between 96.7 and 97.5 °F, does it mean having a temperature of 99.9 °F is high? Let’s see. While a slightly elevated temperature may be a sign that you are getting sick, chances are a number of other factors are influencing your body temperature on a daily basis. As a result, 99.9 is not considered a fever.

In 1868, Carl Reinhold August Wunderlich showed that normal human body temperature averages 98.6. But even then he knew that body temperature varied from person to person, at different times of day and for many other reasons besides illness. Body temperature tends to be about one degree higher during the day than in the middle of the night, said Matthew Kluger, a retired professor and expert in body temperature. “A higher temperature makes us run a bit faster, and I contend that it also revs up our immune response as well,” he said.

Eating, exercise, ovulation and being on birth control pills can all drive up body temperature as much as a few degrees, as can emotional stress, according to a 2001 Japanese study. Age tends to drive down temperature, so an older person with a temperature of 99 might be getting sick, while a younger one with the same temperature could be perfectly healthy, said Jack A Yanovski of the Eunice Kennedy Shriver National Institute of Child Health and Human Development in Bethesda, Maryland.

The method of measurement also matters, with a wider range of normal seen in oral thermometers compared with rectal or ear thermometers. Room temperature, whether you have recently had something cold to drink, even whether you are breathing mostly through your mouth, can also affect oral thermometer readings.

Illness isn’t just about having a particular reading on a thermometer, Jack said, but about having a spectrum of ailments, such as muscle aches or diarrhoea.

A temperature over 100.4, regardless of the person’s normal range, is considered a universal sign of fever and suggests illness. If it is over 104, a person should seek medical attention. “The higher the temperature, the greater the chance of a
serious infection,” Jack said.

Karen WeintraubWhich colour do you choose?

Here’s a question. I heard that people can’t look at a colour in one room and then pick it out of a set of similar colours in the next room. But there are people with perfect pitch, so are there people with “perfect hue?”

“The short answer is no,” said Mark D Fairchild, director of the programme of colour science at the Munsell Colour Science Laboratory of Rochester Institute of Technology. “Colour is almost always judged relative to other colours,” Mark said, and the human ability to remember colours over any period of time, or even from room to room, is extremely poor.

“Based on memory alone, we can probably reliably identify tens of colours, with some people perhaps able to study hard and get up to a hundred or so,” he said. “If we were to learn a systematic way to scale colours, we might be able to get up to several hundred.”

If colours are compared side by side, however, “then we can easily distinguish several thousand colours, and some estimate more than a million,” Mark said. Such ability is somewhat analogous to differentiating tones in hearing, he said. Almost everyone can distinguish tones when they are compared in close succession, he said, but only a very small percentage of people have what is called perfect pitch or absolute pitch: the ability to recall and identify tones after a considerable period of time, without a reference tone for comparison.

“Unfortunately, colour appearance seems to be even more difficult to remember,” Mark said, “to the point that we don’t speak of anyone as having perfect hue.”
C Claiborne Ray