14 replies to this topic

[David Henderson]

Hey everyone.  It's not too hot here today in Columbia, Missouri, but soon it'll get hot this summer.  Here's a little article that I wrote on heat management for bicycling in high temperatures.  I hope that someone finds value in my article.  That's why I wrote it.  Stay hydrated my friends!

Regards,
David Henderson

[thefutureofamerica]

I don't know how meaningful it is, but my best race last year was the Hermann crit, when I had ice socks pinned on my bib straps. It was a really hot day (and one of the year's first) but I wasn't suffering much due to the heat.

Your point about evaporation is a really good one, and why I personally like ice socks better than ice in plastic - you get evaporative cooling, which absorbs ~15X as much heat per ounce of water as warming it from 32F to 100F. Also, once it melts you don't have to carry the weight if it's in a nylon sock as opposed to a plastic bag. Velonews had pictures from the USPRO championships of people using nylon stockings that way...

[2slo]

thefutureofamerica, on 30 May 2012 - 02:51 PM, said:

I had ice socks pinned on my bib straps.

A couple years ago (2008?) the day they had the Tour de Winghaven was insanely hot and several of the guys were doing this.  I was dying just standing there watching...

[David Henderson]

Right water has amazing properties.  In my refrigeration classes I was told that water conducts heat 22 times as fast as atmospheric gases can and Dr. Cheung, et al.  says it's 25 times more conductive than air.  Either way, water can capture heat very quickly, and evaporation takes it away.  (Cooling towers efficiently cool large buildings using these principles).  Water temperatures below 70 (21.1C) degrees  can actually remove body temperature faster than the body can produce it.  Being exposed to 50 (10 C) degree air temperature isn't generally dangerous, but being immersed in 50 (10 C) degree water can quickly become life threatening.  Such are just a few of the effects and power of water.  I hope this was clear in my article.

[tarmac72]

Ice socks/stocking for road races - easy hand ups and as stated evaporation and weight
Ice bags for crits- shorter time, leave a corner open for drainage pointed down and your rectal temperature will be cooler

[Nerrej]

Great post man.  I'm still a beginning/commuter and I plan to just ride my bike to and from work but I know how STL summer is and its going to be hard to avoid the hot days.  I'll be sure to use some of your tips to help me keep cool this summer.  Thanks again.

[David Henderson]

tarmac72, on 31 May 2012 - 06:17 AM, said:

..... and your rectal temperature will be cooler

Well said sir.  I generally avoid bringing a rectum into the discussion, but this time it seems to work nicely.  

"Cooler heads prevail".    (Or if you prefer:  "Cooler tails prevail")

[kwn220]

Don't forget the obvious, train in the heat. Most people spend their entire day in air conditioning and develop very little heat tolerance. The body is capable of making adaptations to heat but one must train for it. Heat tolerance can be a big deal in endurance events and training in hot weather is the best way to bring this about. I go as far as wearing one or two extra layers under my jersey even in warm or hot weather. I've also been know to put on my arm warmers. Since I'm bald, I always wear a skull cap to protect form sunburn but you could also add a cap under your helmet. Believe me, when you take this stuff off for a race, it feels good. Be cautious, you can overheat. If you feel like you are, just peel off layers You probably want to buildup to this and don't have to do it everyday. Another thing I do is go to my fitness center and sit in the sauna for about 20 min. I think that sitting in a sauna of 120-130 degrees can change your perception of what's hot. Train for the heat and follow David's suggestions and you might gain an advantage over others who don't.

[tarmac72]

David Henderson, on 31 May 2012 - 11:03 AM, said:

tarmac72, on 31 May 2012 - 06:17 AM, said:

..... and your rectal temperature will be cooler

Well said sir.  I generally avoid bringing a rectum into the discussion, but this time it seems to work nicely.  

"Cooler heads prevail". (Or if you prefer:  "Cooler tails prevail")

i've been told i have my head up my .... most of the time, so applicable

[acoggan]

kwn220, on 31 May 2012 - 11:23 AM, said:

Heat tolerance can be a big deal in endurance events and training in hot weather is the best way to bring this about.

Exercising in the heat is essentially the only way to induce heat acclimation/acclimatization, i.e., passive exposure has only a limited effect.

[David Henderson]

Thanks everybody for your comments.  From this forum and several others I have adopted many of your comments and added them to the article resulting in an estimated 21.23% improvement.  I appreciate your comments.  Stay cool everybody!

Cheers,
Dave

[digyourownwhole]

Thank you for posting this, D!

[David Henderson]

From feedback and discussions,  I've found and added a section that quantifies  and illustrates the effectiveness of evaporative cooling:  (I think it's pretty interesting)

"The reason for wetting your clothing is that water is 25 times more conductive than air, and as the water evaporates from your clothing/skin, the captured heat is removed with the water.  (cooling towers efficiently cool large buildings using these principles).   As an illustration of the effectiveness of evaporative cooling, consider the results from the following simple test done with canteens covered with water soaked fabric covering versus canteens with dry fabric covers with only 3 hours of temperature exposure:

Starting Water Temperature (both containers): 74 degrees F
Air Temperature: Varied; between 98 and 101 degrees F
Ground Temperature (in direct sunlight): 119 degrees
Water in Plain Canteen after three Hours in Sun: 117 degrees
Water in Canteen with wet cover, hung in sun but in breeze: 75 degrees

Evaporative cooling produced a 42 Fahrenheit degree difference in the interior water temperatures (23.4 degrees Celsius difference)!

Now imagine that the water inside the canteen is your blood and vital organs.  You can further increase the rate of evaporation by riding your bicycle because you will create air currents that constantly lower the vapor pressure at the immediate surface area of the water.  Wind plus water equals cooling.   Pre-wetting your clothing can temporarily save  (or extend) body fluids and can increase your stay-time to exhaustion during a heat stress event."

[Rodgers]

Dave I just wanted to say thanks for that post, I used two frozen bottles on the RR last weekend and they really kept me cool for 2/3 of the race until they melted so I could drink them.   I also kept my suit zipped up and wet, great advice. Thanks again!

[rich pierce]

I use an ice filled collar around my neck when racing MTB in the heat.  It's like one of those little pillows that go around your neck for the airplane "seat of discomfort".  It melts as I go along, lasting about 40 minutes at 90 degrees.  Out in the sun on the road it melts faster and sometimes I am so wet that water runs out of my shoes.