genejockey 

I used to only know one refill station, till they closed it. I posted in the NorCal forum and learned about 3 or 4 more, so now I can pour water on myself to my heart's content .This was a BIG help a couple weeks back when it got up to 97 on my Sunday long ride!

tomato coupe

Sure you do. Drinking is what allows you to sweat, which leads to cooling.

scottfsmith

But the science says it is 6x as effective to put the water directly on your skin. See the article in my original post above. Here is a graph from that article.





This plus top pros doing it is all the evidence I need. But doing it myself the difference is obvious. I had a 92F humid ride yesterday and it felt like 70s to me with the extra water cooling.

tomato coupe

The article compares immediate temperature drop due to evaporation with temperature drop due to conduction (ingested water). It does not consider the temperature drop due to evaporation that results when you sweat off the ingested water.

The pros are not spraying water on their heads in lieu of drinking -- they are doing both. (No pro would forgo drinking in order to spray water on their head.)

scottfsmith

True, the study did not address the cooling factor of sweat (no study seems to have). But look at a sweating rider and you will see it is not nearly as efficient: the visible sweat is spotty because it needs to be absorbed through the jersey before it is exposed to the wind and different parts of the body sweat at different rates. You will need to be absolutely dripping with sweat before you are getting the kind of cooling a good splash will do. It also requires work to digest and sweat that water, and that will also deplete electrolytes. The overall conclusion of that paper is, "To return to our original question: which is better, to drink or to pour water on yourself? In our opinion, if you are thirsty or if it makes you feel great, go ahead and drink your water, but if you're looking to cool down, feel free to toss your water – on yourself."

Only absolute idiots would forego drinking. Let's stick to reasonable hypotheses.

tomato coupe

If no one should forgo drinking, then your initial post is just stating something that's been known for centuries -- evaporative cooing is an effective way to lower body temperature. Do it if you have extra water after you are finished drinking.

scottfsmith

Yes, it should be obvious, but some people posting above don't seem to think it is good to douse themselves with their extra water. Obviously running out of drinking water is the worst-case scenario so one must carefully keep track of carried water levels.

BTW I looked again for studies, here's one not of athletes but it shows that self-dousing in really hot weather lowers heart rate by 5bpm and halved the perceived discomfort: https://jamanetwork.com/journals/jam...rticle/2752456. Here is one about workers obtaining a measured advantage from wearing water-soaked T-shirts: https://www.frontiersin.org/articles...medium=twitter. When I do yard work in 90+F weather I have a special shirt I soak and put on. Its awesome until it dries and I hit it with the hose soon after.

tomato coupe

I think you're misinterpreting the preferences of other people as arguments against the effectiveness of evaporative cooling.

Again, I don't think anyone needs to be convinced that evaporative cooling works.

scottfsmith

Maybe.

Yes but I wonder if people are thinking that drinking and sweating is just as good as drinking plus adding some extra water on top.

tomato coupe

No one has made that argument. I think you're looking for disagreement where there isn't any.

Calsun

Putting a piece of wet sponge or even a cloth rag in the helmet can help keep the head a little bit cooler. It will do nothing for the reflected radiant heat from the pavement and that is what is doing the most to heat the rider and not the ambient air temperature. In a room if one stands close to a wood fire they will feel considerably hotter and this is from the radiated heat. In Arizona where so many died the ambient temperature was at 120 degrees but the surface temperature of the pavement was 170 degrees. With the poorly insulated homes with single pane windows in Arizona the indoor ambient temperature could be at 75 degrees but the radiated heat from the walls, ceiling, and windows could be greater than 120 degrees for the occupants.

When I lived in southern California my riding during the summer months was at night when it was cooler and now sun rays to contend with in terms of body temperature or increasing my risk of skin cancer. Drivers tend to be less harried and less aggressive in the evening hours after the end of the commute period.

scottfsmith

I learned this the hard way a couple days ago, I walked my dog in bare feet with most of the pavement in the shade, but just two minutes of walking on sunny pavement burned my feet, ouch. I should take out my IR temperature gun and see what kind of griddle I put my feet on.

Re: evaporative cooling, any evaporation will help cool from any kind of heat (it is an endothermic reaction) so it should still help with radiant heating. In the east I think the radiant heat is relatively less of an issue compared to the west, it doesn’t get quite as hot but we have much more humidity so 90F air alone can be extremely annoying. I plan most of my routes on wooded roads so I am maybe a third of the time in the sun on average.. another way to stay cooler.

Putting any kind of water-holding sponge or towel etc on seems like it would also help with cooling, I personally prefer with the super tight bike outfit how the evaporation is less than a mm from your skin so there is less insulation from the cooling, you get nearly all of that endothermy cooling your core. But you have to continually re-ante on the water coating.

rm -rf

Here in the midwest, one of the nice things toward the end of a hot ride is having more water remaining in the bottles than I will want to drink. A quick squirt on my knees and left forearm is so refreshing in the airflow as I ride along. It only lasts 30 seconds or so, and doesn't solve the hot weather problems, but I like it. That's why I top off both bottles at the mid ride store stop -- I won't drink both of them in the last 20-30 miles. I like having extra.

Winter tights on a warming day: if the ride gets a lot warmer than I originally expected, splashing water on the knees is very cooling. (It lasts longer than the summer bare knees splash too)

downtube42

I'm often wearing sun sleeves on hot sunny days; a bit of water squirted directly to the sleeves feels super cool for a few minutes, as it evaporates. Obviously only done when water availability is not an issue.

On hot days I wear a cycling cap under my helmet to keep sweat out of my eyes. I've found soaking the cap in water is nice, as well. Typically I've done that at a stop, not while riding.

rsbob 

Most bikes can hold two water bottles, so those would be good simply for hydration. For cooling, partially freezing a third bottle and putting it in your middle jersey pocket would provide a bit of cool as well as water for your head. read under Marginal Gains (Josh Poertner), the third bottle would add a bit to being more aero IF you are taking an aero position on the bike. Extra weight might be a slight penalty,

CAT7RDR

On one uncharacteristically hot beach ride a few years back, I was overheating and in danger of heat exhaustion.
At Seal Beach in SoCal there are outdoor showers for the surfers and swimmers.
With my full kit on, I showered with the cool water and that saved the day.

noimagination

Jeez, a 4 hour ride in the heat on only 28 oz or so of water would have me "...feeling weaker and becoming more irritable," too. On a ride up into the mid-80's (deg. F) I would drink 4 x 26 oz bottles. Less in cool/cold weather. On a "hot" ride in the upper 80's or above, or if it's humid, even that wouldn't be enough. I'd add another 26 oz bottle to that, for a total of 130 oz (ed.), and most/all of that would be electrolyte replacement drinks, not just water. Even then, I'd be drinking after my ride and probably wouldn't pee for a couple of hours after stopping.

IMO, you're crazy in the head. I'm not a doctor, but you could be flirting with some serious health issues if you ride with the type of fluid and electrolyte deficits you're talking about.

I'm serious. You could die.

Broctoon

I said further up in this thread that I prefer to drink my water rather than spray it on my body. (I'll spray some on my face if I have plenty.)

But there's a third option I find useful, similar to Calsun 's suggestion to use a wet sponge or rag in the helmet. I have a thin scarf with highly absorbent gel beads sewn into it. I don't remember who makes it, but it's a commercial product, not just a DIY. I leave it soaking for a few hours before a ride, then take it along in a ziploc bag. About mid day or whenever I start to get hot, I can tie it around my neck. It helps a little, by cooling through evaporation and transferring that effect through my neck, where lots of blood flows. Because the beads hold much more water than a plain fabric scarf, it is effective much longer.

scottfsmith

Someone should make a jersey out of that stuff, you could probably get 10lbs of water into it by soaking before the ride. I've seen those cooling towel things, but I don't want to deal with keeping it well-wrapped while riding.

I just did a ride in 95F and I hardly sweated at all. I hosed myself down before starting and kept myself continually drenched.

genejockey 

One thing I discovered years ago - decades, really - when I used to run in the summer heat and humidity in Southern Pennsylvania is that while splashing water on myself generally was cooling, the thing that cooled me off fastest was pouring cool water over my head and neck. I'd come back from a run when it was in the 90s and be just dripping with sweat, and starting to feel overheated, but 10 or 20 seconds running the hose over the back of my head and neck made a huge difference.

This is why, when I overheated on a ride and someone offered me water to drink, I asked her to pour it on my head instead.

Rick_D

Interesting topic.

Here, our heat is combined with low humidity, e.g., hottest day this year was 106 and 20%. Riding in that I sweat so much I can't keep up with the drinking side of things and will use all of two bottles, water and some kind of sports drink. There's nothing extra to dump on myself.

Good way to monitor if you're drinking enough is a before and after weight comparison. Water is a little more than 1 pound/pint, if you've dropped several pounds then you need to drink a lot more.

Was surprised to learn during the Tokyo Olympics that warm water distance swimmers must be monitored for heat exhaustion/stroke. Lucky me, I'll never need to plan for that.

Fredo76

I used to wet down my denim vest for AC on my motorcycle - works great. But to ride across Phoenix on a hot summer afternoon required head-to-toe, full clothing soak-downs with a hose, at one end of town, and a refresh at the other end an hour later.

I absolutely agree with the OP about the effectiveness of smart external coolant application. On my bicycle, I've long spritzed my ears for comfort, and if I start getting seriously hot, do exactly as the OP says, pouring some down the back of my head.

Jrasero

On a really hot day yeah a wet jersey will keep you cooler and should dryout quickly so you don't get swampy. However the better play for most rides unless it's serious hot is just a cold towl on the neck