body temperature

[pasquallie]

I am doing a science fair project on body temperature. My question is "Does age affect your body temperature?" I can not find any research that will answer or give me any information on this topic. Could you please help me?

[deleted-71576]

Interesting question. I've never heard it discussed. There are a number of disorders that can effect temperature regulation, but they are not, per se, due to aging.

Sounds like a nice original project to do.

BTW, when you look up what normal temperatures are supposed to be, you will find that the old data (98.6 degrees F) may not really be the accurate normal body temperature. People have more recently studied this, and may have new, better data.

[Andrew121]

Hi zzzzdoc, just like pasquallie. I am also working on a similar project on body temperature. Few days ago in an article I read that our physical temperature drops at night, as part of the normal circadian pulse. And maximum female persons reach their minimum physical temperature earlier than men, People who feel most awake in the evening have lower nocturnal temperatures. Now I have few questions regarding this.

1) How our sexes influence our body temperature cycle?

2) What is the relation of our age with our physical temperature?

3) How the outside climate conditions affect body temperature?

4) Will exercise at different times of the day affect our body temperature cycle?


Any help will be appreciated very much.

[MelissaB]

I may be able to give you a more detailed answer tomorrow, but I know that (1) may be due to hormones. Women taking certain hormone pills have different body temperatures at night than women not taking those pills. Personally, I notice the difference the first few days I take these pills because I wake up and/or can't get to sleep because I'm too hot!

I suspect that exercising at different times of day will also affect your body temperature, because I know that if you have insomnia, it's recommended that you exercise an hour or two before bedtime. Granted, that's partly just to tire you out, but I think it's also to cause changes that will trick your body into thinking that it's time to sleep. Body temperature could be one of the changes, but I don't know that for certain.

[deleted-71576]

Andrew:

You need to narrow things down. You are suggesting a bunch of variables, when you should only be studying the effects of one independent variable on a dependent variable.

You are posing some interesting questions. Start by doing some research on Google, Answers.com, Wikipedia, or Ask.com. When you have things narrowed down, you can start asking us more directed questions.

[deleted-71576]

OK, I'll help a little. But I still think you need to narrow your topic.

From Wikipedia on Thermoregulation:
http://en.wikipedia.org/wiki/Thermoregulation

Variations due to circadian rhythms:

In humans, a diurnal variation has been observed dependent on the periods of rest and activity, the maximum ranging from 10 a.m. to 6 p.m., the minimum from 11 p.m. to 3 a.m. Sutherland Simpson and J.J. Galbraith did much work on this subject. In their first experiments they showed that in a monkey there is a well-marked and regular diurnal variation of the body temperature, and that by reversing the daily routine this diurnal variation is also reversed (Simpson & Galbraith, 1905). The diurnal temperature curve follows the periods of rest and activity, and is not dependent on the incidence of day and night; in monkeys which are active during the night and resting during the day, the body temperature is highest at night and lowest through the day. They then made observations on the temperature of animals and birds of nocturnal habit, where the periods of rest and activity are naturally the reverse of the ordinary through habit and not from outside interference. They found that in nocturnal birds the temperature is highest during the natural period of activity (night) and lowest during the period of rest (day), but that the mean temperature is lower and the range less than in diurnal birds of the same size. That the temperature curve of diurnal birds is essentially similar to that of man and other homoiothermal animals, except that the maximum occurs earlier in the afternoon and the minimum earlier in the morning. Also that the curves obtained from rabbit, guinea pig and dog were quite similar to those from man.

These observations indicate that body temperature is partially regulated by circadian rhythms.

This Chart from 1911 is the classic one showing diurnal variation in body temperature, ranging from about 37.5 °C from 10 a.m. to 6 p.m., and falling to about 36.3 °C from 2 a.m. to 6 a.m.


Variations due to women's menstrual cycles
During the follicular phase (which lasts from the first day of menstruation until the day of ovulation), the average basal body temperature in women ranges from 36.45 - 36.7 °C (97.6 - 98.6 °F). Within 24 hours of ovulation, women experience an elevation of 0.15 - 0.45 °C (0.2 - 0.9 °F) due to the increased metabolic rate caused by sharply elevated levels of progesterone. The basal body temperature ranges between 36.7 - 37.3°C (97.6 - 99.2°F) throughout the luteal phase, and drops down to pre-ovulatory levels within a few days of menstruation. Women can chart this phenomenon to determine whether and when they are ovulating, or to aid conception or contraception.


Variations due to other factors
In Simpson's & Galbraith's work, the mean temperature of the female was higher than that of the male in all the species examined whose sex had been determined.

Meals sometimes cause a slight elevation, sometimes a slight depression—alcohol seems always to produce a fall. Exercise and variations of external temperature within ordinary limits cause very slight change, as there are many compensating influences at work, which are discussed later. Even from very active exercise the temperature does not rise more than one degree, and if carried to exhaustion a fall is observed. In travelling from very cold to very hot regions a variation of less than one degree occurs, and the temperature of those living in the tropics is practically identical with those dwelling in the Arctic regions.

There is some anecdotal evidence that with humans suffering from auto-immune conditions the regulation of bodily temperature does not behave in a normal way. So much so that when fighting viruses the body temperature actually falls.