I’m considering purchasing “arm coolers” etc for desert riding. I understand how they keep you cooler than other types of fabrics. But how do they perform vs. exposed skin? (for cooling only, not UV protection) I googled, but didn’t find any real documentation.
I’m a little skeptical because all the wicking fabrics say they protect in cold weather better because wet skin cools like 20 times faster than dry skin, which seems woudl be the case in hot weather as well.
Thanks for any advice.
I ride every ride in the summer with arm coolers in sunny socal for sun protection. In my opinion, they are not cooler than exposed skin unless you pour water on them. When it’s dry, you’ll need to keep pouring small amounts of water frequently to keep cool. Otherwise, they are slightly hotter than no sleeves my .02 - E
I’m not sure about arms, but there was a study awhile ago about keeping cool and what to wear.
Turns out a tech shirt is best, followed by a cotton shirt, followed by bare skin. Not sure how the cotton shirt is better than skin, but w/e…
Was that about how to keep cool while exercising/sweating? If so, I’m a little puzzled by the rankings.
Looks like I’m way off…maybe I somehow reversed the order in my head or something?
Can you read more than the abstract? I don’t have an account…
I also found Effects of moisture absorption by clothing on thermal responses during intermittent exercise at 24°C. Even though I can only read the abstract, I think that one states cotton absorbs moisture and thus keeps your body temp lower?
Seems OSU’s access to peer reviewed journals is down for the moment.
I think you article is the one I remember…
No documentation necessary–just basic physics/science.
We often think counterintuitively when it comes to thermodynamics because when we hear “evaporation” we initially think HEAT.
As Mr. Nelson taught us in high school Physics by squirting rubbing alcohol on our bare arms, “Evaporation is a COOLING process.”
Arm Coolers cool in two ways:
They effectively double–even triple–the surface area of what is covered through evaporation; the skin on your arms and both inside and outside surfaces of the Arm Coolers (thin, breathable, dimpled surfaces augment this further). And no matter how “dry” the relative humidity, you’re arms are sweating and wetting your skin. This applies both night and day. Cycling at 20 mph also amplifies the effect.
Their white surface reflects ambient sunlight (ultraviolet radiation = heat).
x2 for markvoss.
from experience in the high desert of NM, the dry arm coolers feel no cooler than bare arms - also no hotter IMO. When wet, they are very good at cooling, to the point of having cold arms on the bike.
I wear them LOTS, for the UV protection. Anecdotally, I feel more fatigued after several hours if I do not cover my skin, even if I don’t feel hot. For this reason, I also don’t go shirtless.
I don’t sweat enough on my arms to keep them wet, they are always dry. With tech shirts, my sweat rate on my chest is more than sufficient to keep evaporation going. Maybe I’m an outlier, but I’ve ridden every day this summer with the coolers and barring pouring water on them, I’m hotter with them than without.
No, no, you have that exactly wrong. Documentation is absolutely necessary.
It might not be basic physics but basic transport phenomena tells you that it is far from given that the energy lost due to the supposed increased evaporation can be more than offset by decreased energy loss due to a new layer between the skin and a convective surface in addition to the loss of radiative ability through that area of your skin.
Not to mention that the temperature and sun conditions will make a large difference as well. In hot and dry environments there’s a crossover point where you go from radiating heat to the environment to receiving heat from the environment.
So documentation of increased work capacity with the use of these things in different environments is absolutely necessary. Documentation of the core body and skin temperatures while doing it would be helpful as well.
No documentation necessary–just basic physics/science.
We often think counterintuitively when it comes to thermodynamics because when we hear “evaporation” we initially think HEAT.
As Mr. Nelson taught us in high school Physics by squirting rubbing alcohol on our bare arms, “Evaporation is a COOLING process.”
Arm Coolers cool in two ways:
They effectively double–even triple–the surface area of what is covered through evaporation; the skin on your arms and both inside and outside surfaces of the Arm Coolers (thin, breathable, dimpled surfaces augment this further). And no matter how “dry” the relative humidity, you’re arms are sweating and wetting your skin. This applies both night and day. Cycling at 20 mph also amplifies the effect.
Their white surface reflects ambient sunlight (ultraviolet radiation = heat).
I hear all these things and I believe them. Yet in practice, those clingy, cooling fabrics invariably make me overheat when a singlet does not.
This only makes sense to me. If I am running on a cold day, a long-sleeve clingy fabric keeps me warmer. I certainly would not wear a singlet on such a day. How they are supposed to reverse their behavior on hot days seems counter-intuitive
I’m from Las Vegas and I use the Desoto arm coolers. As far as subjective feel, the arm coolers seem about the same as nothing on arms, but over a long ride I think it helps prevent sunburn. They do help keep the arms warmer if caught in a thunderstorm, and definitely are cooler when wet. I tend to use them more for longer rides or when it’s cooler in the morning and warms up later.