Showing posts with label body temperature. Show all posts
Showing posts with label body temperature. Show all posts

Jun 17, 2010

Feeling Cold, pt. 2 - effect of insulin on body temp


As you may recall, I recently started doing some data recording of my basal body temperature at waking and before bed. Through that data, it was pretty obvious that my core body temperature (CBT) is more than a bit lower than the normal 98.6 degrees (F). I have consistently run 96.5. Having established my initial baseline for my A-B-A data set test for my upcoming experiments on increasing my own CBT, I was doing some Google-research when I stumbled upon a preview of an article to be published this coming October in the medical journal, Diabetes.

The article is entitled "Insulin Causes Hyperthermia by Direct Inhibition of Warm-Sensitive Neurons." The objective of the research was to examine the role of the metabolic signal insulin in the control of core body temperature. The findings demonstrated that insulin can directly modulate hypothalamic neurons that regulate thermogenesis and CBT which indicated that insulin plays an important role in coupling metabolism and thermoregulation at the level of anterior hypothalamus. Since I myself don't have a subscription to the Diabetes medical journal nor feel like spending $45 to read something I probably can't understand in the first place, I'll just assume they are correct until one of you readers points me to contrary medical research.

According to a summary medical article on Medical News Today "New Link Discovered Between Core Body Temperature and Insulin," while much research has been conducted on insulin since its discovery in the 1920s, this is the first time the hormone has been connected to the fundamental process of temperature regulation:

The scientists found that when insulin was injected directly into a specific area of the brain in rodents, core body temperature rose, metabolism increased, and brown adipose (fat) tissue was activated to release heat. The research team also found that these effects were dose-dependent - up to a point, the more insulin, the more these metabolic measures rose.

"Scientists have known for many years that insulin is involved in glucose regulation in tissues outside the brain," said Scripps Research neurobiologist Manuel Sanchez-Alavez, who was first author of the new paper with Bartfai lab colleagues Iustin V. Tabarean and Olivia Osborn (now at the University of California, San Diego). "The connection to temperature regulation in the brain is new."

...

In work coordinated by Osborn to characterize these neurons and their transcriptome (all of the messenger RNA molecules in a cell, which reflect the genes being expressed), the team noticed something unexpected - a messenger RNA for an insulin receptor.

"We were surprised to find the insulin receptor," said Tabarean. "The insulin receptor is very well documented in the pancreas and in other peripheral tissues. But in the brain, it was not clear and we definitely did not know about its existence in warm-sensitive neurons."


The article goes on to explain the methodology, then draws some conclusions:

The authors note that while their new paper illuminates a key piece of the puzzle of the body's metabolic processes, it also raises many intriguing questions: How does insulin get to the brain's preoptic area - does it cross the blood-brain barrier or is it produced locally? Are diabetics, who are insensitive to insulin in peripheral tissues, still sensitive to insulin in the brain; if so, could this dichotomy be used in the development of a new therapy? Could scientists find a way to use these new insights to increase energy expenditure for the purpose of weight loss?

Unlike the rodents in the medical tests, I'm not really in much of a position to stick a syringe into my brain and inject a bit of humalog to see what happens. So, I thought I'd ask for volunteers. Just kidding!

It does, however, give me an idea for an experiment to try: determining the effect deprivation of all insulin from my system would have on my CBT. Given the above, would my CBT actually be lower if I had, say, 24 hours of no insulin whatsoever? It would be a pretty simple test to complete, perhaps at my next scheduled site change. Don't worry, I'd couple it with a complete fast as well so my blood sugar levels shouldn't rise too high... that in and of itself would be pretty interesting to know as well: what is the rising rate of one's blood sugar if nothing is ingested?

As always, please don't try this at home. I don't mind screwing up my own body processes in the name of science, but I don't want to worry that I'm messing with your own. But, if you do decide to give it a try, don't hesitate to share the data!

Jun 12, 2010

Feeling cold?

The other day I stumbled upon an interesting article entitled "Chronic Fatigue Syndrome and Low Body Temperature" by Dr. David Jernigan of Hansa Center for Optimum Health. He is of the opinion that a low body temperature creates a "happy home for viruses and chronic infections, and is a sign of degeneration and gradual cellular death." As the body’s core temperature decreases all cellular energy also decreases thereby leading to profound and chronic fatigue that is not relieved by sleep. In his article he also summarizes the effect a cold body core temperature has on the circulation system, including peripheral circulation problems and cravings for high sugar based foods to increase the body's heat production. As you probably know, these are two issues every diabetic has to deal with on a daily basis.

According to Dr. Jernigan, it is essential to monitor and graph your core body temperature upon awakening but before getting out of bed and sometime between 8 and 10 pm. Evidently the healthy body has daily temperature fluctuations (diurnal) with the coolest temperature upon awakening in the morning hours of 6-8 a.m. and the warmest being in the evening between 8-10 p.m. There should be a difference between the morning and evening temperature, in a healthy person, of at least 0.9° F (0.5° C).

The core body temperature is the temperature taken under the tongue. After doing some research (okay, okay, after Googleing a bit) it appears that it is best to use a digital basal thermometer as they record much smaller temperature changes than an ordinary thermometer. As for the temperature you want to see, Dr. Jernigan maintains the optimal core body temperature is 98.6-99.6°F, with 98.6° F being the minimum.

So, today as part of my continued life-logging project, I am off to purchase a basal thermometer. I've already gone online and purchased an iPod app for tracking blood temperature. I settled on BT Monitor.

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6/13 Just a followup comment - my core morning temp turned out to be 96.5! That is more than 2 degrees colder than it is supposed to be. Hmm...