Your normal core temperature will probably be about 37C (98.6F) but depending on a few other factors it may vary slightly (such as the time of the day, whether you’re tired, asleep, hungry, or where you measure it). Though, under normal circumstances the variation isn’t great: 36.12 - 37.8C (97.02-100.04F). It has to be that warm in order for the chemical reactions that keep you alive, to take place. To get an idea of how important this is try and wash a greasy plate in cold water. Now, instead, use hot water. It’ll be a lot easier. Grease, egg yolk or gravy etc. dissolve much more efficiently in warm water and the same thing happens in your body. The chemicals you rely on just work a lot better when there’s a little heat around.
However, in biofeedback therapy it’s the Peripheral Skin Temperature (PST) that floats our boat. We’re not so interested in your core temperature (unless you are running a fever or have hypothermia for some reason)
Here’s what to expect: We attach a thermometer to your finger (in Biofeedback Ireland we use an electronic one attached to a computer, a bit of elastic tape and the ring finger on your left hand). If you’re relaxing your blood vessels will open up (dilate), blood flow will increase and your skin will get warmer.* More importantly, you can see it on the monitor in front of you and you can learn to control it. You’ll find that as you relax, change the way you’re breathing, or what you’re thinking about, you’ll see your skin temperature increase. It’s our job to keep everything else constant (like the temperature in the room). That way you can be sure that it’s something you’re doing.
Basically, when you increase or decrease your peripheral temperature you are changing the way blood is flowing in your body. Knowing how do this helps everybody especially people managing chronic conditions.
* This is one of the reasons we use a duvet or blankets at night. Assuming you relax when you sleep, your skin gets warmer and you turn into a radiator. Because you’re radiating all that heat into the air you cover yourself with a duvet or blankets to trap it so you don’t get cold.