Working in research affords me the luxury of playing with incredibly cool and expensive toys. Toys I would otherwise never touch if I weren't in this line of work. As a result, this task was one I had completed prior to joining SFZ, and only submit it as a task because... well... its an incredibly cool and expensive toy that I get to use for free. So here goes:

"The Vitalsense(c) Integrated Physilogical Monitoring System, part of the Minimitter (www.minimitter.com) family of patient/subject monitoring systems, can receive transmissions from multiple miniature, wireless, temperature sensors. Core body temperature is sensed by the ingestible Jonah™ capsule. Dermal temperatures are recorded from hypoallergenic, non-irritating, adhesive dermal patches. Both sensor types are disposable, but designed for multi-day use under demanding physical and environmental conditions. Both types of sensors use low-power radio frequency transmissions to communicate with the Monitor."

Scientists have often debated that internal "core" temperature is different from the temperature read in your mouth, armpit or anus. The claim is that they are too sensitive to your external environment. Swallowing a temperature sensor essentially gets away from that problem by putting a sensor in the subject's "core"; their stomach. It takes a nice long trip down the intestines, which also remains a more accurate reflection of overall body temperature than the typical aforementioned sites.

The first few pictures are of the family of products, the packaging and the pill activation itself. The final picture is a visualization of the temperature in my lab mate's stomach over a 41 hour and 40 minute span (2 sleep cycles). A few items of interest:

1) She used a diet coke freshly purchased from a vending machine. That valley hitting 93 degrees fahrenheit is that soda briefly cooling her stomach. Within a bit over an hour or so, her stomach had reached a more homeostatic temperature.

2) It seems as if in her first cycle of sleep, her body temperature dropped before/when she got to bed, but steadily rose throughout the night (with 1 more significant drop, REM onset maybe?).

3) Her body temperature was highest at around 3-4 oclock, which is the most stressful time of the day for us, and also carries implications regarding her circadian rhythm (see final quote).

4) Her second sleep cycle, unlike her first, seemed to just drop steadily throughout the night. I also started loosing data points at around 5am, but I'm guessing she knocked the monitor away from her during sleep (it's meant to stay within 1 metre from your body when reading sensor transmissions).

What's interesting about the difference in her temperature patterns during both sleep cycles is that temperature before, during and after sleep are (according to some research) a reflection of your body's internal circadian pacemaker. The following is an excerpt from "Sync: How Order Emerges From Chaos in the Universe, Nature, and Daily Life" by Steven Strogatz:

"By studying sleep in relation to the cycle of body temperature (rather than in relation to the time of day or any other external variable), [Czeisler] had discovered a natural reference frame, a natural measure of what time it is in the body. When viewed from this perspective, data that had previously appeared 'jagged' and 'random' suddenly lined up and snapped into place. How long a subject stayed asleep did not depend on how long he had been awake beforehand; it depended on when he fell asleep in relation to his cycle of body temperature."