Training & Nutrition - Really hot weather

This may have been answered already, but I keep getting error messages when I try to search the forums, so here goes.

I find that even when I eat properly and drink huge amounts of water/gatorade and so on I get serious problems on hot weather rides -- my head pounds, my body sags and I lose all energy and will to go on. The last time I felt almost physically sick, and it took 15 minutes resting in the shade, followed by an ice cream before I felt half human enough to complete the ride, which was only 50-60 km to start with. I drank lots of water the night before, more in the morning before I started riding and at least 4 bottles during the ride, so it wasn't just straight dehydration. But it was scary. Any tips to avoid problems in really hot weather riding?

Perhaps pace yourself better? I think some people don't realize they can't perform as well in humidity and heat, so even though they're pushing along at their normal pace, they overtire and overdo it, then end up getting sick in the end.

Also, take breaks as needed in the shade, and if you can, try to get in extra carbs (pasta meal, for instance) the night before. It takes a lot of energy to ride in the heat. Before your ride, you should get some extra carbs in your body, and carry a couple of powerbars with you to eat during your ride.

Koffee

Sounds like you're getting a mild case of heat exhaustion. You need to take it easy in the heat. Some people's bodies are better than others at dealing with heat. Living in the great white north you don't get heat year-round like others, so your body isn't as acclimated to it. All the water in the world won't prevent heat exhaustion if you're really exerting yourself. Just ease up on your pace, keep drinking, and take more frequent rest stops.

I'm a little rusty in my conversion but is that around 31-38 miles?

I'm a little rusty in my conversion but is that around 31-38 miles?

Absolutely, Conversion is approx 1.6

I agree you're suffering heat exhaustion. Had it several times myself. Though you may think you're drinking enough, you probably need to drink more. When I lived in Saharan Africa, I'd drink--on average--8 liters of water a day, often more. If you're riding in the heat/sun and exerting yourself, you're going to need more than you think. Make sure you're not only well-hydrated before you start, but while you're riding, also. And things like Gatorade or other Oral Rehydration Solutions are important to get you salts--if you don't have any of those, your body won't be able to absorb the water! Are you on a low-salt diet at all? If so, stop. You might find that you're craving salt during this period, also. That means you need it. If you're doing high-intensity exercise in extreme heat, sweating a lot, then you probably need more salt, also. Water's no good if you can't absorb it.

There's no inherent reason why you shouldn't be able to do this--just make sure you're hydrated, and as posters above stated, ease your way into it. Your body needs to 'learn' to sweat enough to keep you cool.

-max



PS There ws a good posting about this in the commuting forum: I tried searching, but couldn't find it. Try there, though--it was up about two weeks ago.

Glaceau (SP?) Smart Water.

Up your water intake to 70 oz. every hour.

I drink a mix that is 70 oz. of Smart Water, 30 oz. of gatorade and 40 oz. of water.

Drink mineral water when after your rides. You could add salt tabs to your ride hydration. I've heard Tylenol will help if your riding in unfamiliar temperature ranges (higher heat) because it thins the blood. I've been told, nothing scientific, that if you live in colder climates you have thicker blood, and in warmer climates, its thinner. This may benefit you - but talk to a doctor first.

But ya, sounds like heat exhaustion; I've had it hit me on the 13 mile mark of a daytime run here in Texas (100 degree range - and nasty since we haven't seen rain in a long time, I can't remember when it actually rained here last in Temple).

The best advise would be to discuss this with your health care provider, and see what they recommend. Heat injuries aren't something to look for quick answers. And no offense, nobody here knows your medical history, background, genetics, etc. so we're all just grasping at straws.

and it took 15 minutes resting in the shade, followed by an ice cream before I felt half human enough to complete the ride, which was only 50-60 km to start with.

Ah! I see the problem. Eat the ice cream BEFORE the ride!

One thing to make explicit: Humidity is important. A high humidity will make it harder for sweat to evaporate, making it harder for your body to cool down. Our low humidity in Arizona means that, even when it is 110F/42C, we cool off pretty well. But change that equation even a little, like moving the relative humidity to 30%, and it is a lot harder to cool off. So, keep an eye on the humidity as well as temp.

The solution is the same as the other posts, though: ease up on your pace.

Personally, I notice the heat having a huge impact on both my running and riding. On the bike, I need to make sure I have Gatorade and not just wter, or else it makes me feel sick in the stomach, and I also need to eat more on the bike when it's hotter.

And ok, I'll be the first to say it, what about that problem with drinking TOO much water? It sounds like you really had a crap load of water before the ride. Maybe you diluted your electrolyte concentration too much?? (Or is all of that just a myth??)

I'm a little rusty in my conversion but is that around 31-38 miles?

Yes, that's right.

On my long rides in the heat, I think my Camelbak makes all the difference. I'm able to drink cold water for several hours whereas the water bottles get warm over this time.

I've read alot that too much water can be a problem, but I really don't understand why.

hyponatremia

Google or Yahoo! for it. People have died from this, but none from dehydration (while exercising).

One thing to make explicit: Humidity is important. A high humidity will make it harder for sweat to evaporate, making it harder for your body to cool down. Our low humidity in Arizona means that, even when it is 110F/42C, we cool off pretty well. But change that equation even a little, like moving the relative humidity to 30%, and it is a lot harder to cool off. So, keep an eye on the humidity as well as temp.

The solution is the same as the other posts, though: ease up on your pace.

As an AZ guy myself,I always find it amusing that I stay essentially dry while moving but the floodgates open as soon as I stop. When I lived in more humid climes (MA, NJ or PA) I'd sweat bending over to tie my shoes. :)

I think I'd suggest a little more strongly that the OP seek the advice of the doctor. I'd hate to see him miss a metabolic diagnoses like blood sugar problems, etc.

How used to riding in the heat are you? How often (times per week)? Have you slowly ramped into it, that is been riding regularry from spring to hot summer?
Al

One thing to make explicit: Humidity is important. A high humidity will make it harder for sweat to evaporate, making it harder for your body to cool down. Our low humidity in Arizona means that, even when it is 110F/42C, we cool off pretty well. But change that equation even a little, like moving the relative humidity to 30%, and it is a lot harder to cool off. So, keep an eye on the humidity
This is true up to a point. I use to ride a lot in Houston throughout the summer, 100+deg 90% humidity and it didn't feel as hot as 116 F/ 10% humidity. The dryness really drains you much quicker. The body will sweat as much as it needs to keep the skin damp. If the air is dry and you are moving sweat evaporates immedately, but your body needs to keep sweating constantly hard to keep cool, but there is a limit to how much moisture you can put out. That drains you very fast. In Houston I could go longer in the high humidity without turning beet red and getting dizzy. Not only to mention the intense sun and heat actually physically hurt a bit when its over 110 real temps.

The low humidity is great when its 105 and below, 90deg actually feels cool and pleasnt to the skin when its dry. 115 is a whole different situation.

Obviously you know this, but just putting some balance on the whole 'its a dry heat' thing. Dry heat is great when your sipping a cold drink in the 105deg shade, but to be approached with great care when maximally exerting oneself in full sun.

Al

This is true up to a point. I use to ride a lot in Houston throughout the summer, 100+deg 90% humidity and it didn't feel as hot as 116 F/ 10% humidity. The dryness really drains you much quicker. The body will sweat as much as it needs to keep the skin damp. If the air is dry and you are moving sweat evaporates immedately, but your body needs to keep sweating constantly hard to keep cool, but there is a limit to how much moisture you can put out. That drains you very fast. In Houston I could go longer in the high humidity without turning beet red and getting dizzy. Not only to mention the intense sun and heat actually physically hurt a bit when its over 110 real temps.

When I'm out hiking in the Mojave Desert, I wear loose fitting long sleeve shirts and pants and a hat. It keeps me cool (compared to direct sunlight) and prevents dehydration. Maybe if you are riding in that kind of dryness, you should cover up as well to prevent dehydration and hyponatremia if keep constantly flooding yourself with water.

When I'm out hiking in the Mojave Desert, I wear loose fitting long sleeve shirts and pants and a hat. It keeps me cool (compared to direct sunlight) and prevents dehydration. Maybe if you are riding in that kind of dryness, you should cover up as well to prevent dehydration and hyponatremia if keep constantly flooding yourself with water.
When I hike in the summer I do the same, long sleeve, big brim hats, etc.
I don't go for more than 30min at max intensity, or 1hr at moderate in the hottest days, so I don't drink that much during exercise. I've lived here 15yrs. and have always exercised (mostly running) and know what works and when to stop.
I also know that the body sweats more at higher humidity and to make it worse the higher humidity makes that sweat less effective. That is why humid is worse. But in my message above I speculate that above 110 even with dry air there is something else going on where heat index is no longer a good metric - its based more on personal experience than known research, but there is little research I can find on 115F/10% vs. 100F/80% for example. Most of it is 80F/45% vs. 80F/80% type comparisions.

Al

This will be long because there is a lot of misconception about hyponatremia.

Hyponatremia: dilution of electrolytes. Your blood volume is sufficient but your electrolytes are dangerously low. There was a lot of media attention to this recently so people really freak out about it (esp med tent staff at races) and it seems to be overdiagnosed. I had med tent staff hammering me about it recently in a situation where it was simply not possible.

A key note about hyponatremia: it takes a lot to dilute yourself this much. It typically presents in much longer races (marathon, ironman) and only in the slower racers who take water at every aid station. It presents with idential sympotoms to dehydration, but usually later -generally people tend to present with dehydration-like symptoms hours after the race. They have also consumed a ton of water without urinating. If I remember right, what kills you is swelling (edema) of the brain. While the poster sounds like he/she drank quite a bit, at 125lbs I have needed 5 bottles of water on 50mi desert rides. If sitting in the shade eating ice cream helps (I believe there is actually a fair amount of salt in ice cream) he is probably overheating and dehydrated rather than hyponatremic. (Bty, test this by weighing yourself before and after riding. You should NOT gain weight from drinking to much water.)

Possible solutions: 1) throw tons of water over your head, down your neck, under your armpits (there is a plexus there so it will cool lots of blood going to your core), groin, etc. Even in humid enviornments where sweat doesn't evaporate as fast this will help. I don't really sweat enough to keep cool so this is vital for me. 2) add electrolytes to your drinks. Gatorade doesn't have nearly enough. I've started adding drops of "elete water" (eletewater.com) to whatever tastes good to me. I picked the stuff up in Arizona and have been really happy with it. If I forget it, I notice that I really crave salty foods later (wierd for the gal with a sweet tooth).

p.s. As for sweating to cool off -the cooling is from the actual evaporation of the sweat because the change of state from liquid (sweat) to gas (evaporated sweat) transforms heat energy from your body into the kinetic energy of a moving gas particle. That is why in a humid enviornment you sweat but don't cool because the sweat simply pools on your skin rather than evaporating and cooling you.

p.s. As for sweating to cool off -the cooling is from the actual evaporation of the sweat because the change of state from liquid (sweat) to gas (evaporated sweat) transforms heat energy from your body into the kinetic energy of a moving gas particle. That is why in a humid enviornment you sweat but don't cool because the sweat simply pools on your skin rather than evaporating and cooling you.
All good information.
As to sweat cooling, right on. But as I understand the max sweat rate is perhaps 2L/hr (never measured) typically 1.5L/hr and rarely measured above this. (The max absorbtion rate is ~1.5L/hr.) But what is the evaoporation rate in 115/5%/20mph?
What if it is 115deg out and such low humidity with wind so that even at max sweat rate all evaporates immediately, cools you, but it is not enough? I've also read studies that indicate that wind (say from cycling movement) when temps are high actually increases body temp (blood vessels come to surface of skin, blood is 98-100deg or so, but air temp is 115 so blood doesn't cool, so body can only rely on evaporative cooling not the convective which works at sub 100deg actual temps.

Al