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Designed by two Stanford professors, the Avacore Core Control is a heat extractor for the human body which will provide an athlete the ability to recover more quickly than natural methods such as sweating. An interesting product, but with a price tag of $3000, I doubt the the public will get their hands on this anytime soon. This instructable will show you how to build your own CoreControl for about $150.

Before you get started, please familiarize yourself on how the CoreControl works. You can check the published study that goes in depth with the CoreControl. I was able to replicate the functions for my DIY CoreControl using the design specs from this study.

FAQ about the Corecontrol.
More Published studies (bottom of page)
Check out instructable user emckee1's blog on his DIY CoreControl with improvements!
diybodyheatextractor.blogspot.com


Summary
When our body overheats, it goes through a thermoregulation process to expel excess core body heat.  The palm of our hands is one of the body's "radiators" to expel heat. Why the palm of the hands? The palms have numerous capillaries which cover a large surface area, allowing the removal of excess heat from the body. The vacuum is supposed to draw the blood to your hands to increase the heat transfer rate. The faster you remove the excess body heat, the faster you will recover from exercise.  

You may have heard about rubbing ice cubes on your wrist to reduce recovery time.  However, this method is inefficient because low temperatures cause the blood vessels to constrict, thereby reducing the blood flow.  The CoreControl applies a similar concept, however, is more effective because it uses a vacuum to draw the blood quickly to the palms, and the controlled temperature prevents constriction of blood vessels.

I built my first homemade CoreControl a year ago.  Due to numerous requests, I decided to build a second one in order to write a detailed step-by-step guide. Let's have some fun!

Step 1: Materials

Materials Needed
  • 4" Diameter PVC Pipe
  • 4" to 3" PVC Reducer 
  • 4" Rubber End Cap
  • 3" Metal Fastener
  • 20' Vinyl tube 5/16" x 3/16" 
  • Long Cuff Neoprene Gloves 
  • Four 3/16" Barb x 1/4" MIP 
  • Two 1/2" FIP x 1/4" FIP Pipe Reducing Coupling
  • 1/2" x 5" Brass Pipe Nipple 
  • Via Aqua Model: VA-302 (Can be found at a pet store, could use any other water pump)
  • OEM Brake Bleed Kit Pump (Can be found at Autozone)
  • Digital Thermometer 
Everything can be found at Home Depot or your local hardware store except for the last 3 items.

Step 2: Tools Needed

Tools
  • Electric Drill
  • 13/16" Spade Bit
  • 1/2" Drill Bit
  • PVC Saw
  • Teflon Thread Seal Tape
  • Pliers
  • Measuring Tape
  • Marker
  • WaterWeld Epoxy Putty
  • Sea-All contact adhesive and sealant
  • Silicone caulk (optional)
  • PVC cement
  • PVC primer
  • Scissors
  • Flathead screwdriver
  • File Sander

Step 3: Vacuum Chamber - Cutting the PVC

  1. Mark an 8"  section on the 4" PVC pipe.
  2. Cut the PVC pipe using the saw.
  3. Deburr the edges with your hands or with the file sander. 

Step 4: Vacuum Chamber - Drilling the Holes for the Heat Transfer Rod (Brass Rod)

Heat Transfer Rod
  1. Mark 4" from the edge with an X. This is where you drill a 13/16" hole to fit the brass rod. It is better to mark the center hole for both sides because if you just drill straight through, you will run the risk of having a slanted brass rod.
  2. Carefully drill both sides. 
  3. Deburr the holes.




Step 5: Vacuum Chamber - Vacuum Hole

  1. Turn your PVC around and mark 2" from the edge. This is where you will insert the 3/16" barb which will connect the vacuum pump.
  2. Deburr the edges with the sanding file.
  3. Once you have deburred the edges, tap the hole with 3/16" barb. Do not overtighten or else you run the risk of stripping the newly created threads. Once it's stripped, you are going to have to start over because this needs to be tightly sealed. Turn all the way to the pipe and remove it. You could leave it on but it will get in the way.

Step 6: Heat Transfer Rod - Sealing It Air Tight

PAY ATTENTION! THIS IS THE MOST IMPORTANT STEP!! GO THROUGH THE PICTURE SERIES TO GET A GOOD IDEA OF WHAT IM DOING!

You don't want to mess this step up or it will get real messy. When I built the first one, I was having trouble creating a perfect seal and this area was the main problem. I have tried many methods to plug up the holes and this was the best solution I came up with. I just tested it and it works perfectly. If you have a better method of sealing, by all means go right ahead. 
  1. Push the brass rod all the way through until you reach the inner wall of the next hole as shown in picture 2
  2. Get you Seal-All ready and place it on the Brass threads and the hole on the other side shown in pictures 6 and 7.
  3. Once that is done, grab the brass rod in the middle and turn it as if you are screwing it in shown in picture 8. This will spread the Seal-All adhesive all around the the holes which will hopefully fill in most of the gaps between the threads 
  4. Screw until you cannot seal the threads inside the pipe shown pictures 9,10 and 11.
  5. Take the two 1/2" Pipe Reducing Coupling and screw them to both ends real tight. Use a wrench if you need to. Again, make sure the threads aren't visible in the inside.
  6. Smear Seal-All all around the couplings
  7. For best results, let it dry for 24 hours. It should be hard and rubbery after a day and It will become rock solid when completely dry.

Step 7: Heat Transfer Rod - Double the Sealing

Once the Seal-All has set, it's time to cover it with the WaterWeld Epoxy Putty. This epoxy is tough and I prefer using this than the 2 part epoxy glue mix. It is much easier to work with and is less messy.
  1. Cut about 1/2" off the epoxy, mix it
  2. Lay the putty around the brass couplings.
  3. Press the epoxy all around with your thumb, making sure it gets into every nook and cranny it can get into.
  4. Let it dry for about an hour.


Step 8: Insert the Barb Hose

Take the three 3/16" Barb x 1/4" MIP and wrap them all with Teflon tape. 2 to the brass rod couplings and 1 to the vacuum hole.

Be careful not to overtighten.

Step 9: Hand Insert - PVC Reducer

  1. Take the 4" to 3" reducer and apply the purple primer. This will soften up the pvc which will form a chemical bond when joining both pvc together. 
  2. Wait a couple seconds then apply the PVC cement on both reducer and pipe.
  3. Push the reducer to the pipe
  4. Now take your Seal-All or silicone caulk and run around the edge of the pipe and reducer. 

Step 10: The Rubber Sleeve and End Cap

I found these neoprene gloves at the garden section in Home Depot. Get the smallest size you can find because we want to have a tight fit around the forearm. I once tried to test this device on my friend but realized his forearm was too small and couldn't get a tight seal. You could use any type of rubber gloves but make sure it has a long forearm and small diameter.
  1. Cut the gloves right below the fingers, we won't need this so toss it
  2. We are going to label both ends the "cut" and "uncut" side. We want to insert the "uncut" side to the PVC reducer shown in the pictures below. You can notice the "uncut" side is wider than the "cut" side.
  3. Place the rubber sleeve and get it centered. 
  4. Take the 3" metal fastener and tighten.
  5. Take the 4" rubber cap and place it on the other end. 

Step 11: The Vacuum Test Setup

We're just about done and now you have to test if it can hold a subatomic pressure aka vacuum.
  1. Cut a small piece of the Vinyl tube 5/16" x 3/16" and insert it to the brake bleed pump and to the vacuum barb
  2. Stick you hand in and have the rubber sleeve all around your forearm and grab the brass rod.
  3. Give it a few pumps and see if the vacuum holds. You may notice the the rubber seal will start to concave into the pvc but don't worry this will create an even more tight seal around your forearm.
  4. Here's a couple scenarios that might happen:
  • If the gauge stays, you have sealed vessal.
  • If the gauge drops quickly or doesn't move at all, you need to plug up either around the brass rod or at the vacuum barb.
  • If the gauge drops slowly, you could plug up and put more teflon tape on the vacuum barb but you can always compensate by pumping more
Once you are done, you can take it off. What I like about this brake bleed pump is that it has a gauge and pressure release valve.

NOTE
You could go all the way to 25 in.HG to see if it really works but don't do it for so long because your hand will get red and feel funny.


Step 12: The CoreControl Setup - Water Reservoir

Depending on what water pump you get, you may have to install a 3/16" Barb into it. If you got the same model I have, this fits perfectly and you just need thread the Barb into the water pump

Find yourself a small bucket to act as the water reservoir. You are going to have to jimmy rig one by drilling some holes to fit the vinyl tubes in. I used a chinese takeout container. 

Step 13: How to Use: the Required Design Specs

Congratulations! You just finished constructing your own CoreControl. Before you use the device, there are two design specs that you must know in order for this to work.
Update
I recently came across a more recent published studies on the RTX CoreControl Glove and I will list them below. The big change is the water temperature from 18 degree Celsius to 10 degree Celsius. This water temperature was chosen based on previous hand immersion studies showing this is the optimal temperature that limits vasoconstriction in the hands. I have only tried the 2005 specifications but I would try the new water temperature.

Design Specifications
Published paper from 2005. 
  1. Water temperature: 18 to 22 degree Celsius or 64 to 71 degree Fahrenheit
  2. The subatomic pressure (vacuum): 35 to 45 mm HG or 1.4 to 1.8 in.HG (edit - courtesy of user "milwaukee" for the correct conversion)
2009-2010
Published paper from 2009.
Published paper from 2010.
  1. Optimal water temperature: 10 degree Celsius or 50 degree Fahrenheit
  2. Subatomic pressure (vacuum): 45 mm HG or 3 in.HG
Getting the right subatomic pressure
The gauge on the brake bleed pump is actually in in.HG. so after you convert, it's around 2 to 3 in.HG. This is what you should aim for. When the gauge drops, you can compensate by pumping more to keep it around that area.

Getting the right temperature
It took a lot of fiddling around to get this right but don't start off with a handful of ice and water. It's too cold. Start off with a reservoir of cold tap water which is just a tad colder than it's required spec but once it warms up, ONE ice cube will bring it down to the right temperature. For example, cold tap water is around 16 degrees celsius, when you use the device and goes past 22 degrees, put ONE ice cube and it will bring down to around 18 degrees or 10 degrees. Only put one ice cube at a time if it needs to go lower.

What happens when there's too much vacuum pressure?
Your hand will get red and feel funny but nothing life threatening

What happens if the water is too cold?
Base on the published paper, too cold of a temperature cause vasoconstriction across your hands. 


Step 14: How to Use: the Setup

This is it, all you have to do is cut up some Vinyl tube 5/16" x 3/16" and hook it up. 

When you hook up the water pump, make sure the water going in is going through the bottom because you don't want any air in the brass rod. Check the notes in the pictures to get the idea.
  1. Measure the water temperature using a thermometer and get it down to 18-22 degree Celsius/ 64-71 degree Fahrenheit
  2. Insert hand, make sure it's tight
  3. Pump the vacuum until 1 to 2 in.HG
  4. Use for 2 minutes
And that's it! 


What am I suppose to feel?
The feeling of being "refreshed" similar when you sit down, drink water and rest for 30 minutes. When I first tested this, I did 5 sets of 20 pushups. After each set, I would use the CoreControl for no more than 2 minutes and on to the next set. In the past, by the time I reach the 4th and 5th set, I start to struggle and slow down. Using the CoreControl, I noticed each set felt like the the 1st and I felt a bit surprised about it since I was expecting to feel the pain.

Now, this could be placebo effect on me and I have nothing to quantify it. I have thought of having a BPM heart rate monitor attached to me to see the time it takes to slow down my heart rate back to normal. In the end, the published paper have shown in their studies positive results so you could take their word for it.  

Room for Improvement
There are definitely ways to make this better.
  • Larger vacuum chamber
  • Increase heat transfer by using a copper pipe, larger pipe or metal dish shape.
  • Box rig for portability
  • Some sort of twist lock for the arm seal
This guide was meant to show you the cheapest route but with a little extra money and ingenuity, you could come up with an idea to improve this. 

Special Thanks
Just want to give a big thank you to fellow redditor/instructable staff 
dworley and redditor coconutketoer for supporting me. This guide would never have been completed if it wasn't for these two.

In case you missed it in the first page, check out this 2nd gen diy CoreControl build in this blog!

diybodyheatextractor.blogspot.com/
<p>Hi people! I made a prototype and I also put up a video on youtube featuring the device, it's a bit differnt to this one but the concept is still the same! I know that my energy is higher using this comparing to not, Iv meassured my performance for different excercises!<br>https://www.youtube.com/watch?v=LQ894nLshCQ</p>
<p>Is there some reason why you just can't plunge your hand into ice water?</p><p>If the point is to just chill the palm, where the transition is between arteries and veins, why not a neoprene diving glove with the palm area cut out?</p><p>Better, save damaging your glove and just shove an ice cube or two in.</p><p>Seriously, what am I missing?</p>
<p>They say that excess cold causes your blood vessels to constrict, reducing blood flow. </p><p>I like to keep a bucket of water, a small towel, and a straw hat for working in the heat. You can wet the towel and the hat, wear them around your neck and on your head and they absorb a lot of heat. Each half hour or so I'll rewet the towel and towel off a bit.</p><p> After reading about this, I'm curious to try it out while excersising. </p>
HI :) Is there any way I could cover the supplies and your labor and you could make one for me? I figure it will still be cheaper than the original and much faster for you to make since you've already done it once than for me to try and figure it out? Thanks.
Have you thought about using a peltier cooled heat pump instead of ice water? <br> <br>by 'heat pump' i mean braided copper cable or something pulling heat from your hand to the peltier, so it won't be as cold as directly grabbing an icy peltier. there are glues [i think loctite?] that will bond metal to metal with thermal conductivity without electrical conductivity (found out the hard way some LEDs with metal backing had that backing wired to ground, and thus the heatsink we were trying to attach them to). <br> <br>Also, it might be possible to retrofit an aquarium air pump as a diaphragm vacuum pump, just gotta figure out a way to attach tubing to the air inlet instead of the outlet. :)
Oh duh, just read the emckee1 page. way better idea than a scavenged aquarium pump
Cheap brass barb fittings here:&nbsp; <a href="http://sites.google.com/site/arctareproducts/home/industrial-parts" rel="nofollow">http://sites.google.com/site/arctareproducts/home/industrial-parts</a>
Nice instructions. I wonder if the whole reservoir could be replaced by one of those external aquarium filters. Just fill it with water and ice
It looks like a new model of the CoreControl is on the market. Only for $895!! <br>I did some research online, and found this website: <br> <br>http://www.corecontrolcooling.com <br> <br>They have tons of scientific studies, and videos there. It looks like the NBA Golden State Warriors &amp; the NFL 49ers have been using this new model. <br> <br>So for all you who doubt, you can stop now :)
This is very impressive. If I pay you could you build and send your prototype to me? I own the commerical version and would love to compare them.
I built something along these lines with a few improvements: <br>Arduino controlled vacuum and water pump <br>larger vacuum chamber and larger (1.5&quot;) copper pipe for cooling <br>faster cuff entry and exit <br> <br>You can see the build log if interested at diybodyheatextractor.blogspot.com
This is great! I love the improvements you implemented and look forward for a complete write up on your build. I would like to post up your blog link into this instructable if you don't mind.
Thanks! Absolutely. It will be a little while before I post a distilled how-to guide since I'm on to a few other projects already but pretty much all the info needed to construct one of these is contained in blog.
I just finished mine, couple comments: <br> <br>- There are plenty of higher diameter pumps, I used 1/2&quot; tubing and this reduced need for an un-needed reducer for cooling pipe, while still maintaining great water flow. I believe my pump is around 250 gph <br> <br>- Buy two 90 degree adapters for the cooling pipe to hose connection, so that both hoses can come off same direction and you can ziptie them together... having them come off in opposite directions is unwieldy <br> <br>- I used a 3/4&quot; pipe, more surface area and my hand still fits fine. <br> <br>- I off-set the pipe to one side, I don't like putting in the middle because the bulk of your hand is only on one side. <br> <br>- Most hardware stores should have a 4&quot;-&gt;3&quot; reducer in rubber, which means you don't need the cement, and makes it much more serviceable. <br> <br>- Buy two 4&quot; rubber caps, when building you can cap both ends and submerge in water to test for leaks. <br> <br>- Be careful which gloves you buy, my first pair had packaging that stapled through the glove, rendering a good 3in worthless. Look up &quot;dry suit cuffs&quot; and for $10 or so you can get latex cuffs specifically designed to be air tight. this seems to be weakest part of design. <br> <br>- If you add a small aquarium heater, you can also use this to warm up. I whitewater and snowboard, plan on using this after some outings! <br> <br>
Thanks for these suggestions. Is the tubing you used 1/2&quot; inner diameter or outer diameter? Also, what kind of connector did you use for the 3/4&quot; pipe to the 1/2&quot; tubing? At my hardware store today, I couldn't find anything that would work for those dimensions. (I'll need to check out someplace larger.) Thanks for any info.
does this work well even when not using immediately during or post workout? <br>
How do I get the sleeve to stay sealed on the wrist or forearm? I have it built and have the pressure and water flow working, but when I have it on my arm it doesn't stay sealed. A rubberband would defeat the purpose of returning blood flow quickly. Any suggestions? Thank you. And someone suggested 6&quot; PVC, which would work better since I have big hands. That would be a better fit for anyone else that has big hands.
I believe that I have come up with a way to duplicate the results of these machines without using one at all - check out my blog on this: <a href="http://realfitfacts.blogspot.com/2012/09/muscle-miracle-no-more-sore-muscles.html" rel="nofollow">http://realfitfacts.blogspot.com/2012/09/muscle-miracle-no-more-sore-muscles.html</a>
Hey, Popular Science just reported on some research Stanford did that showed the glove this is based on is more effective than steroids.<br /> <br /> <a href="http://www.popsci.com/technology/article/2012-08/video-cooling-glove-could-help-athletes-more-steroids-chilling-their-hands">http://www.popsci.com/technology/article/2012-08/video-cooling-glove-could-help-athletes-more-steroids-chilling-their-hands</a>
BTW - I'd like to offer an edit in the suggested vacuum settings listed. <br> <br>35 - 45 mm Hg converts to roughly 1.4 - 1.8 inches of Hg rather than 2 - 3 inches Hg. Depending on your design and build quality, that 3 inches of Hg amy be difficult to achieve and nevertheless appears to be unnecessary. <br> <br>Hope this helps. Thanks again!
It's a surprise to see that someone else has built one of these. I built a similar device based on Grahn and Heller's device 2 years ago using a tiny aquarium pump, a dishwasher detergent canisters, a small insulated drink cooler, a shop vac and a homemade copper coil (for heat exchange). <br> <br>I had some success using the device My experience was that consecutive sets of work felt like the first if the device was use for 3 - 5 minutes before the set. I also noticed that I could perform a larger volume of work: more weight for more reps and sets. A longer duration recovery period after whatever work seemed to improve immediate recovery. I have also used it after a run and have found it possible to go back out and run some more when normally I would have been very fatigued. <br> <br>The device isn't only for weight lifting- it was just a convenient method for me to test it. <br> <br>My setup was pretty noisy and large, so I've decided to upgrade to make it more convenient. There are some good ideas in here gyronictonic which I am going to incorporate. Thanks!
I had to go up to 6 inch PVC. My hands are too big. Just test it out before you buy, and then adjust accordingly.
This was developed by DARPA! Your not going to improve it, or refute it.<br><br>Thank you for the design. Im building one tomorrow.
Very cool (no pun intended, but enjoy it if you like it). I remember reading about this exact same thing being tested as a new hypothermia treatment years ago (using warm air instead of cold). IIRC it was pretty effective at that, and was being looked at as something to add to the standard EMT/rescue kit for cold weather regions.<br><br>This is the first time I've seen it as a cooldown method, but it makes sense that it would work for that too.
I love that you've reduced this idea to an affordable DIY project!<br> <br> Idea: why not flood the whole vacuum chamber with water, leaving some air space if you don't want to suck water into the brake bleed pump?<br> <br> Idea: what about circulating air between the chamber and a heat exchanger in your ice-water bath? You could use Arduino PID to do temperature feedback control on the air exiting the chamber by increasing or decreasing the pump flow rate.<br> <br> Concern: It looks the science is not yet 'settled' on this, to make fun of Al Gore.&nbsp;A recent review paper (2010) of 14 different studies found that the average improvement in exercise performance due to cooling interventions was 4.25%.&nbsp;<a href="http://journals.lww.com/nsca-jscr/Abstract/2010/12000/Effect_of_Body_Cooling_on_Subsequent_Aerobic_and.39.aspx" rel="nofollow">(Review paper link)</a>&nbsp;At a minimum, it seems that your specific exercise routine and timing combined with the use of a tool like this will cause the results to vary greatly. For example, if you're doing anaerobic stuff (weight lifting) it sounds like this doesn't really help, but if you're doing aerobic (soccer) it does.<br> <br>
The vacuum against the palm is necessary to keep the capillary vessels from retracting due to the cold temperatures. Flooding the chamber would negate this and the body's normal self-protective reaction to cold would kick in and minimize the thermal transfer from the core.<br><br>I haven't found the body of the article you cited but it isn't clear that they tested the effectiveness of the avacore glove, but rather, tested more conventional prevailing methods of cooling. There have been quite a few compelling studies and demonstrations during the development of the glove that indicate it is especially effective--for anaerobic activity, in particular. Not to take anything away from Jim Harbaugh, but (my non-scientific opinion) Stanford's football team has been benefiting from using the glove and their record since its use tends to suggest they should continue to use it.
They tested a number of cooling methods, but you're right that it's not clear they tested the avacore glove specifically. I googled quick and there are a number of papers on uses of the avacore specifically but I don't have time to read them now =)<br><br>Part of the question I'm asking though is whether a cold shower (if available) would produce the same results even if in a more brute force way (overcoming your body's cold defense response with... lots more cold water). Do you know how important it is to do this during or immediately after your workout, as opposed to 10-15 min later?<br><br>Regarding air vs. water- water at the same temperature may have a lower perceived temperature and will remove more heat faster because it has a higher heat capacity and conductivity than air. But, I don't immediately see why you couldn't still use it- maybe a degree or two warmer to avoid causing capillary constriction. <br><br>
Looking at the Avacore website, it doesn't look as though there are any studies to see if this actually works - it looks like junk science &amp; snake oil to be honest.
I used to ride my bike 8 miles to class and to a campus job while in college nearly every day. I would always ride fairly hard and especially in warm weather would arrive quite overheated. It would take me 10 to 15 minutes to fully recover typically until I discovered that running the chilled drinking fountain water over my wrists and holding cold water in my mouth helped me recover much more rapidly. When I discovered the lab walk-in freezer I was recovering in a couple of minutes when combined with holding cold water in my mouth until it warmed, repeating etc. It really is quite a bit about getting rid of the excess heat for me anyway. Other issues are lactic acid build up and stuff, but the heat is a biggy.
Making an assumption about your statement regarding lactic acid: the lactic acid issue you refer to is probably not what you think it is. In fact, the earliest work on the glove began by looking at the prevailing beliefs about lactic acid build up and fatigue and the researchers determined that there was no good (modern) science to back up the beliefs about the role of lactic acid in muscle fatigue. The researchers determined that lactic acid was a good thing for muscles and that the fatigue being experienced was actually due to heat build up, thus the investigation began in how to cool muscles quickly.
My way to cool myself is to let cool water over my arms, and wash my face. The arms are important because, although their surface is only a fraction of the whole body surface, they contribute a lot to how hot we feel.<br>Of course, the best of all is a shower. But although something simple, a shower cabin is so difficult to see around --though I remember having seen some at the Brussels airport (the very place I also saw the most bably designed toilets!!, if I may be so bold<br>).<br>-.
Go work out until you're dripping with sweat. Grab the coldest soda can in your fridge, press it against the palm of your hand firmly for five minutes. The soda will be warm and flat and your sweating will be mostly stopped. It's not as efficient as the vacuum method but costs the soda or beer you already have in your fridge.<br><br>Just make sure to not drink the can when you're done, put it back in and grab a fresh one to drink.<br><br>Don't use anything freezer cold though, your circulation will slow down to prevent hypothermic conditions from infiltrating your body (and it hurts).
i beg to differ, there have been plenty of studies, the tech has also been around since the early 2000's. The apparatus works by the common principle of heat is lost or gained throw the head, hands, and feet. By circulating a cool (not cold) flow to the hand this chills the blood by 2 degree's which circulates through the body reheating and chilling again, unlike hypothermia circumstances where its constant chilling which freezes the body to an unsafe level, this process in the opposite is more or less like defrosting a frozen turkey in the microwave where the process is just to slightly heat the temperature but not to cook it and vice versa :D
:creepygusta:
A few years ago while shingling a roof in very hot conditions, a quick for me recovery. Fill the bathroom sink full cold water, bend over and lay your arms (both of them if the sink allows) in the water for 5 to 7 minutes. Near instant relief from the heat, best thing I ever found.
I'm curious if an aquarium air pump could be used (seal a line to the air inlet) as a vacuum pump (you would have the problem of measuring the vacuum still, but i bet you could find a guage with a slightly more modern, scientific way of measuring your vacuum than in.Hg, though i'm not sure how cheap thermocouple gauges are these days). <br><br>I bet if you could find a sensitive enough thermometer you could find the shut-off threshold by measuring the heat of blood being returned through the veins of your wrist (by testing different temps of cooling liquids until you saw the cessation of cooling in the returned blood).
A fellow redditor came to me showing me his immersion circulator that would be great for this type of application. Not sure how he built it but you ask him. Check out his gallery.<br><br> http://gallery.me.com/lachyg#100055&amp;bgcolor=black&amp;view=grid <br><br>
Saw this on National Geographic's program called Fight Science a while back. I think it was in the episode &quot;Ultimate Soldier&quot;. Doesn't look like junk science to me.<br><br>http://natgeotv.com.au/tv/fight-science/<br><br>

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