Mythbusters: No Pain, No Gain

So I finally watched Mythbuster's episode entitled No Pain, No Gain. First, they visited Stanford University to determine what pain testing methods they would use for their experiment:

1. Heat pain tolerance
2. Electrical pain tolerance
3. Capsaicin pain tolerance - the active ingredient in spicy hot chili peppers
4. Cold pain tolerance

They settled on testing cold pain tolerance by setting up a contraption that would measure the amount of time that a person could tolerate leaving their hand in ice water, which was maintained at 1 degree centigrade.

Myth: Women Tolerate Pain Better than Men
CONFIRMED!
On average, women could withstand cold pain for 100.4 seconds, while men could only withstand it 84.3 seconds. I've always believed this; women are made to withstand childbirth after all!

Myth: Swearing Increases Tolerance to Pain
CONFIRMED! (but I have my suspicions)
On average, the five subjects could tolerate about 30% more cold pain when they swore than when they didn't swear. However, since the same five subjects immersed their same hands during the non-swearing sessions as they did for the swearing sessions afterward, I wonder if the thermal nociceptors (pain sensory receptors) in their hands might have habituated and adapted naturally. When winter comes, we all have to habituate to it. The same temperature doesn't seem so cold the second or third time around, does it?

AND LAST BUT NOT LEAST......

Myth: Redheads Have a Lower Pain Tolerance
BUSTED! In fact, possibly the reverse???
On average, non-redheads tolerated 79.1 seconds of cold pain, while the redheads could withstand 132.2 seconds of cold pain. I always knew redheads were bad-asses!

So this brings up some interesting questions. In my blog entry entitled Redheads and Pain Tolerance, I cite the studies of Dr. Edwin Liem whose experiments showed that redheads were more sensitive to pain, including cold pain and heat pain. The discrepancy between Dr. Liem and Mythbusters may be related to methods, possibly to type of pain tested, or may not have anything to do with pain at all.

There are different types of nociceptors for different types of pain - thermal, mechanical, chemical, and sleeping/silent. The Mythbusters experiment only used thermal stimulation; whereas, Dr. Liem's experiments used both electrical stimulation and thermal stimulation. It also seems that the equipment Dr. Liem used to test thermal pain tolerance was more sophisticated than Mythbusters (or complicated depending on how you want to look at it). Also, possibly to account for the myth above that women have a higher pain tolerance than men, Dr. Liem restricted his redhead study to women only, whereas Mythbusters tested both male and female redheads. Any of the above could account for differing results.

Also, Dr. Liem's original experiment, which showed that redheads need more anesthesia in surgery than others, may not have accounted for differences in metabolism rates of the drug used for the experiment (desflurane). Some people may metabolize the drug faster than others and therefore will require more of it (thanks to Celtic Curls for hooking me onto this theory).

In any case, this Mythbusters episode only raised more questions for me than it answered. And my redhead studies continue.....