I’ve been thinking about to cool myself during really hot races. Many people put ice in their hats and that works great, but it requires slowing down quite a bit every mile; the ice doesn’t last that long, you may miss ice, a lot of races do not have ice every mile or at all.
I like to be self sufficient and this morning on a snowy, sub 20 degree trail run, when the last thing that should have been on mind was on my mind: how can I get myself cooler while running?
**CO2 cartridge: **
To avoid weight, use 40g Big Air mtb CO2 containers which are made from lighter aluminum, not steel like the 16g cartridges. Attach an inflator head and let a little bit out systematically to make the container cold and quickly screw it very tight again. (if not all the air is let out at once, you can keep the CO2 container from getting too cold) Do this repeatedly and hold one in each palm. Maybe rig up a handheld bottle strap system to hold a bottle and the CO2 with the CO2 pressed up against an artery to take the precious cool blood back to your core. I would have to test how often, how much to let out, and how long the CO2 would last. But, it’s worth a try, because keeping the core temp down in really hot conditions is one heck of an advantage.
Who wants to bust out their chemestry text books and do the math on the amount of cooling energy per ounce for the container, compared to ice? PV=NrT anyone?
“clever”, Thanks! I guess that’s better than a typical ST poster suggesting I see if my core temp can be kept lower by putting the CO2 where the sun doesn’t shine with a cord attached to the inflator attachment to tug on periodically… Thanks!
Not to completely shit on this thread but hasn’t every study shown that there’s pretty much nothing one could employ on the run that actually cools down your core. Dumping water on your head, putting ice here or there, whatever… while making you feel better (more placebo than anything), it doesn’t really cool you down.
It’s been a long time, but I have done this calculation in thermodynamics class.
You’ll do better with a fluid undergoing a phase change, like many times better in terms of the amount of heat taken away. That’s why ice is pretty effective at cooling things off.
So, instead of CO2, make a stop at auto zone before the race and shove a can of freon up your rear end as you run.
Kevin, you’re exactly right when suggesting using a fluid undergoing a phase change. CO2 is compressed to a liquid at 900 PSI in steel cylinders.
As the liquid CO2 is ejected from the cartridge, it ‘boils’ and changes phase into its gaseous state. As more and more liquid boils down, the vapor pressure remains constant until the liquid is boiled off. After this time, the vapor pressure drops precipitously until all the gas is discharged from the cylinder. Generally, during actuation of CO2 gas delivery systems, if the gas is discharged with the cylinder in the ‘up’ position, only gas is dispelled from the cartridge. However, if the gas is discharged with the cylinder in the ‘down’ position, and with gravity affecting the liquid CO2, along with the gas being dispelled, some liquid CO2 is also ejected. This liquid CO2 instantly turns to dry ice, sublimating quickly into a gaseous state.
I do know that in very hot conditions, I can run faster at the same heart rate when I use ice in a hat and in my race suit. Placebo? Maybe. But maybe we’re measuring the wrong variable when attempting to measure core temperature. “Placebo” has become such a valid construct, there being so much evidence of physiological changes when there is a “placebo” affect, that either placebo itself is just as valuable as what was originally attempted to have been measured, or the wrong variable was being measured. Consistently experiencing a faster pace at the same heart rate during the same run after using ice, to me, is good enough for me to attempt to keep my body’s temperature down.
But, all of that aside, if one were to use ice or the CO2 idea all of the way through the race, slowing down the inevitable increase in body temperature, could not hurt.
What has worked best for me especially many hot years in Kona is a one piece suit and constantly shove ice down around your kidneys (midsection)…nothing works better to take your core temperature down.
David
The company I work for sells high end cooling systems to the US Military for helicopter pilots and tank crews. I’ll give you my two cents on the subject coming from someone who has personally sold cooling systems for some of the most demanding temperature requirements out there for the past 7 yrs and also has a graduate level engineering background. Note that the systems we provide are vapor compression (like your fridge) but rather pump cooled liquid to a vest worn under a soldiers flight gear (like wearing a radiator). In our ever present quest to field cooling systems for the average infantry soldier on the ground who is very weight constrained, we’ve examine many different systems and technologies. None of them are effective enough at a physiological level and yet practical (i.e. you’re not lugging around 10lbs of batteries, etc). The military has examined hand cooling in a manner much more complicated than you described. What they found was that your hand basically needs to be in a vaccum environment to bring your blood vessels to the surface to have any appreciable cooling effect. There are some commercial products out there that do this…i think one is called Avacore. It’s defnitely not race portable though. We’ve examined targeted cooling on specific parts of the body (groin, kidneys, back of neck, etc) but again you can’t get enough cooling into such a tiny surface area when combining the mass flow rate of blood past it.
So would your concept work? as others have said it would but only for a placebo effect. But it’s important to note that the placebo effect is sometimes enough. If you think you’re cool and comfortably (even if your body truly isn’t) then it might be enough to keep you going. Really this placebo effect could work as long as the environment you’re in isn’t so extreme such that you “think” you’re ok but your body really is at risk of heat casualty.
I don’t know if your system would work, but something you might want to think about is the CO2 cartridge getting TOO cold and causing frostbite or freezing to the skin if it comes in contact with the person using the system.
Me, I bought on of the Frog Togs cooling towels and draped it over my back under my tri suit. I simply poured water down my back and it would be quite cool for 10-15 minutes as the water evaporated. The effect lasted slightly less during the bike leg as it evaporated faster in that event than it did during my run. All I had to do in the bike is have a water only bottle in one cage (make sure remember which one), and give it a shot of water (the colder the better), when you feel the effect diminishing. On the run, I found cool water at water station (IM Augusta), and that sufficed until no longer needed when it started to rain.
I also dumped ice down my compression socks at every stop when the heat was at its maximum, and a few chunks into my sun guard sleeves helped a lot too. Between all of that, I stayed relatively cool throughout the whole event. I was NOT running for a podium or age group spot though, I was pretty much just racing myself and a few friends so I had the ability to take the time to get the ice and water as I went through the event.
The company I work for sells high end cooling systems to the US Military for helicopter pilots and tank crews. I’ll give you my two cents on the subject coming from someone who has personally sold cooling systems for some of the most demanding temperature requirements out there for the past 7 yrs and also has a graduate level engineering background. Note that the systems we provide are vapor compression (like your fridge) but rather pump cooled liquid to a vest worn under a soldiers flight gear (like wearing a radiator). In our ever present quest to field cooling systems for the average infantry soldier on the ground who is very weight constrained, we’ve examine many different systems and technologies. None of them are effective enough at a physiological level and yet practical (i.e. you’re not lugging around 10lbs of batteries, etc). The military has examined hand cooling in a manner much more complicated than you described. What they found was that your hand basically needs to be in a vaccum environment to bring your blood vessels to the surface to have any appreciable cooling effect. There are some commercial products out there that do this…i think one is called Avacore. It’s defnitely not race portable though. We’ve examined targeted cooling on specific parts of the body (groin, kidneys, back of neck, etc) but again you can’t get enough cooling into such a tiny surface area when combining the mass flow rate of blood past it.
So would your concept work? as others have said it would but only for a placebo effect. But it’s important to note that the placebo effect is sometimes enough. If you think you’re cool and comfortably (even if your body truly isn’t) then it might be enough to keep you going. Really this placebo effect could work as long as the environment you’re in isn’t so extreme such that you “think” you’re ok but your body really is at risk of heat casualty.
Jeff,
It’s this and stuff you had posted in the past that made me stop worrying about trying to cool myself during races because it doesn’t make a damn bit of difference besides the placebo effect. I’d always dump water on my head and jam ice everywhere I could and all it did was give me blisters due to really wet shoes and socks.
