Keeping Cool in the Shadow of Old Italians

In the high desert here north of LA, this time of year we ride very early in the morning when the air is still hopefully cool, but it's also rather humid, and DEAD CALM. The dead calm is a welcome change from incessant winds, usually in the afternoon this time of year, but all day long during spring, fall and to a lessor extent, winter.  

The calm does have a downside though, and it can be very uncomfortable, or in extreme cases maybe even life-threatening. This because if you climb a long hill or otherwise really exert yourself, making a sustained push into Zone 5, when you get to the top of the hill or end of the Strava Segment and pull over to catch your breath and hydrate you can actually get even HOTTER. 

With the high morning humidity in the 60-70% range, stopping means no wind, and probably no shade either. Even in the shade though, the lack of any breeze means your body's evaporation cooling system doesn't work, and your core temp can soar. I've been more aware of this lately bc I now have a short-haired dog I walk ever morning, and dogs don't sweat, they cool themselves by panting and evaporating moisture off their nose and mouth, and by standing broadside to any wind. 

 

There is often a solution to this still air however, and it was discovered by the Italian physicist Giovanni Battista Venturi and published in 1796.

The Venturi Effect states that when the flow of air is constricted two things happen.

1. The air speeds up
2. The pressure of the air decreases by a commensurate amount

We're obviously interested in the first, but the second effect is what makes the carburetor in a car operate as the low pressure draws gasoline into the air-stream, effectively creating an optimal fuel air mixture. So how do you get a restricted airflow while on a ride? Usually by getting between two buildings, fences, or occasionally a large stand of trees like Cyprus Trees that grow straight up like walls.

It's really striking how much of a difference this can make, especially since energy = mass * velocity squared. That extra velocity means a lot more work is getting done and those beads of sweat will soon be gone and your discomfort with it. 

As a pilot I feel compelled to point out the Venturi Effect is also responsible for the fog that forms on the tops of wings when aircraft pull high Gs. This is because the wing's topside is curved, while its bottom side is flat, so the air is accelerated along the topside, lowering the pressure and with it the temp of the air. When the air temp drops, especially in humid conditions, water-vapor becomes visible.  

There, now you have something to contemplate while out riding, and a way to stay cool in still & humid conditions, plus, doesn't this image just look cool? BTW, wanna guess why your CO2 cartridge gets so cold when you use it? :)

Upgrade Your Water Bottle Now!

 I often start my rides with temps in the 70s or 80s, but they end in the 100s, so I have learned from experience the tremendous difference between CamelBak's Podium Ice and all other bottles. Seriously, the Podium Chill aren't worth the water they displace, because you could pack the bottle with ice, fill with water, and the loss in volume when the ice melts is less than the 3-4oz you lose to thicker insulation in the Podium Ice. 

Bottom Line: It's Podium Ice or warm Gatorade.

So why the "News-Flash"?, because the small silicone cap on the  inside of the lid has been flagged as a choking hazard, so these (and all other CamelBak) bottles are now on sale for up to $11 off, making these wonderful, but expensive $26 bottles a once in a lifetime bargain. Oh, and if you're one of the few people left on Earth who still use a Polar Bottle, for God's sake upgrade your gear!

I have two stations for water bottles on my Pinarello. The Red one on the down-tube is for Gatorade, and the Blue one on the seat-tube is for water. I actually prefer the pale blue one, but this one is more distinctive, so a better illustration.

I have quite a specific management protocol for hydration using these bottles, as I live in the high desert and it's very hot and dry here. 

The Gatorade bottle gets filled about half full of the crescent shaped ice my ice maker supplies, but I make the Gatorade from powder and water that sits overnight in the coldest spot in my refrigerator, so it's usually partially frozen. I add Emergen-C powder to the Gatorade powder, pour in the quasi-frozen water and shake. I then put the entire bottle in the freezer while I dress & shower. The insulation prevents the mixture from freezing and ruining the bottle, which it ABSOLUTELY will do! 

The pure water bottle is packed with ice. If you have crushed ice, use it. Whatever ice you use, don't add any cold-wicking water to the bottle until you absolutely have to while out riding. Solid ice has very little contact surface with the walls of the bottle, so it will last a lot longer if you don't fill it with water. I can fit a Zefal Magnum water bottle on the seat-tube, which is where my pure water goes. It's a great option, filled with ice, if you only have warm tap water to refill with on your ride. Its much larger size makes it a better option than the Podium Chill bottles bc it holds so much more ice.

When you need more Gatorade, take the cap off and hold it in your mouth, the same one you're going to be drinking with, and WITHOUT taking the lid off the bottle holding melted ice, squirt the very cold water into your Gatorade bottle. Replace the cap you've been holding in your mouth. NEVER take the lid off of both bottles at the same time as an unlucky gesture like trying to keep your bike from falling over, sliding, etc. leaves ALL of your fluids dumped into the sand. This could be fatal, or at least life-threatening (probably not, but it's a very, very bad feeling to see all your hydration spilled on the ground). 

When you have an opportunity, fill the bottle with ice and melted water with the coldest water you can find, and repeat the process to make more Gatorade. This is the ONLY time the lid should come off of your water bearing bottle, and only when the lid is on and tightly shut on your Gatorade bottle. The idea is to sacrifice cold water for cold Gatorade bc warm Gatorade sucks, and doesn't do anything to cool you off that just sweating would. Try to keep the bottle for water only ice by topping up your Gatorade bottle.

When you get to the end of your ride they won't  be enough ice left to chill a full bottle, so try to judge how much water you can add and still end up with cold Gatorade when you use it to make Gatorade in your front bottle. I often can only top up my Gatorade bottle with chilled water at this point, and have to fill my water bearing bottle with warm water, but that's still a great problem to have after 4-5hrs of riding in 90-115F heat.

PS: If you just have to have pure water along from the start, consider buying an ice-cube tray that makes giant ice-cubes - like 2" squares. Walmart sells them and so do others. The larger the cube the longer it takes to melt into the water that's in contact with the walls of the bottle. It works, but it's a  PITA to work with giant ice-cubes.