Should temperatures rise during sleep?
© 2012 Roy Benaroch, MD
“My son is 5 and he has no signs of being sick. But I have been noticing that his body is hot to the touch and his temperature is high (101 – 102) while he is sleeping. In the daytime he is usually around 98.6 or 99, but it worries me when he sleeps because it always goes high. Is this normal?”
Normal body temperature varies throughout the day. The lowest point is usually from 2-6 am, rising about 1 degree F through the day until a peak in the late afternoon. Measured temperature also varies with activity and ambient temperature, and can be influenced even by hunger and sleepiness.
It is a myth that 98.6 is “The Normal Temperature,” just like it would be a myth that 5’10” is “The Normal Height” for adult men. 98.6 is considered the middle of the range of normal, but even that isn’t very accurate, as different people will vary around their own “normals”. The 98.6 is more of historical interest than a medically exact measurement. It was figured out in the 19th century using thermometers that were incorrectly calibrated, and it’s actually wrong– but we’re kind of stuck with it now.
Since your son isn’t acting sick at all, why are you taking his temperature? An elevated measured body temperature can be a sign of illness, but really that’s only when a child is acting sick with symptoms. A measured temperature that’s higher than expected in a child who’s acting well and feeling well is probably just normal variation rather than a sign of disease.
If you’re worried, take him in for a good exam with his doctor, and bring your temperature logs. Write down the actual numbers from the thermometer, and write down how you measured them (what kind of thermometer). Don’t rely on ear temps or those skin-sensor devices, they don’t work to accurately measure temperatures.
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