You do acclimate and use common sense, don't go riding at 1:00p. Summer in S. FL at 7:00a its 85F and 85% RH by 6:00p its 93F and 50% RH. So on weekends its morning rides and weekdays its evening after 6:00p. Even if you acclimate you still sweat, so take at least 24oz/hr of liquid. I moved here from East Bay, CA where it got to 110F but the humidty was 18%, the first year was tough, now the heat/humidity doesn't bother me so much.

OK, somebody might as well say it: When the temps and humidity get crazy as they are now (predicted high of near 100, humidity ridiculous), I say the he** with riding and stay indoors. For me riding is something I do for fun. Training, shmaining...riding in these conditions is not fun -- not even if I had a Gatorade tanker as a support vehicle!

Actually, Gatorade & other sports drinks make me gag. Tastes like flavored spit IMO. When I ride in "normal" summertime heat I do plain water, or water with a bit of lime or lemon juice and a couple TSP of sugar. And pre-hydration of course. Plus maybe a banana in the jersey pocket. Or stop en route for a snack.

Yesterday with the temp around 96 and sauna-like humidity I went to the nice air-conditioned gym and did my core and upper body workout. Then I went into the pool. Then at home I stayed indoors and did a bit of work on my basement man cave project (it's nice and cool in the basement). The bike can wait till things get a bit more reasonable later in the week.

And no, I'm not a morning person.

FWIW - I find that riding in the heat has made me acclimate to the point that the heat does not bother me as much as it used to - then again it's not the heat but the humidity. I try to drink water all day long to always stay prehydrated. On 1-2 hour rides I take water in one bottle and gatorade in the other - unlike some I don't mind the gatorade but it has to be the orange flavour. One 2+ hour rides I also take the camel back and usually stop for refills at a local stores or borrow a water tap from someone.
My biggest problem is sweat getting in my eyes, burns like heck - will have to resort to a sweat band or something like it - any suggestions?
Performance riding shirts with front zippers are a must and I have bought a couple without sleves for added cooling effect, just need to put on SPF protection.

I use [two bandannas] layered into dough rag with a tail that cover my neck like the French foreign legion hats... I sweating so much last week that drips were coming off my handle bars right out of my gloves.

I also think the "headsweats" ready made rag works OK, but I still think two pieces of cloth work better. than one thin piece for sure. If you get a tail wind in the heat, and you are sweating, sometimes there's nothing you can do. But even then, I carry a wad of paper towels that I can dab into my eye sockets and get the sweat away.

I really don't know whether someone really "acclimates" to heat or not. For sure there are gradual, seasonal changes that do in fact change the some of the characteristics of your blood. But on the other hand, I also think, it's a "mind thing" in that if you are a healthy person, and you ride at a conservative pace, you can in fact enjoy riding in what anyone else would call absolutely crazy weather.

I was riding around town yesterday afternoon with "worst" of the heat at 100 and an index of 104. I stopped in at two airconditioned houses for snacks and drinks. In each case, when you go back outside you have to "accept" the heat for a few minutes, pace yourself, and then 20 minutes later yours sweating and crusiing andv everything's fine. I ended up with 38 miles, probably lost 3 pounds even though I ate and drank about 3 cokes and 4 bottles.

I hate the heat and haven't seemed to acclimate much after a year in Hawaii. I typically go through two 24 oz bottles an hour, one water and one sports drink. Since I eat a gel and a bar each hour as well, I'm not sure I really need the sports drink, but it does make for some variety. I'm too scared of running out of water to pour any on me.

I have insulated Polar bottles but I find them awkward to squeeze and drink from, so I usually use one normal bottle and one Polar to refill from. I start with ice and cold drinks but I'm usually drinking warm water after an hour or two since all the water along my rides is from park drinking fountains. Using a Camelback would be nice but I find it makes me feel much hotter by blocking all the wind on my back and adds to saddle soreness.

Does anyone use a fancy base layer under their jersey? I notice the pros use them a lot, but it's hard to imagine adding another layer that cuts the wind and traps air would really cool me down.

Obviously, each to his/her own - but I love riding in the heat, and feel if you take the advice given here concerning hydration and electrolytes, unless you have pre-existing conditions that prohibit it, riding in the heat should give you absolutely no problems at all. Once you get used to the sweat dripping off you, you can then relax and enjoy your time in the sun.

I rode hard throughout the heat wave experienced here on the east coast and rode at all times of the day - including the middle of the day when the temps were at their highest, and would return after my rides to those ominous newscasts about how the best way to beat the heat is to simply stay indoors and don't venture out unless absolutely necessary - that advice followed by several pieces per day about how the heat killed this 90-year old who, owing to Alzheimer's, shut off the air conditioning and closed all the windows, or that 85-year old who succumbed to congestive heart failure complicated by the heat - all followed by the "so, whatever you do, don't go out in this heat!"

If you really dislike the heat, that's fine - but, if you are healthy and like riding, I would not skip riding just because of the heat.

My two cents.

Caruso

This drink mix has been working for me.
To make about 8 large bottle mixes:
1 cup sugar
1 1/2 teaspoons salt ( about half regular salt, half lite salt for potassium)
2 packs natural lemon koolaid

2 heaping tablespoons in a snack size ziplock bag for one large water bottle. Approximately 100 to 120 calories. I bring a few bags to mix at water stops.

This has the same amounts of carbs and salt as gatorade.

Richard:

That is some ride - how long did it take you?
I agree with you regarding dehydration and would stress also replacement of electrolytes.
Keep those elements replenished and you will be amazed at how comfortable your body can feel in extreme heat.
Congrats again on what sounds like a great ride.

Caruso

Summertime doubles, I quit trying for time, but the general idea is to get away with a 100, usually in less than 6 hours, and usually before noon. The the second hundred miles is thought of as a recreation ride, with the only other "ride" factor being - scheduling water/ice breaks in negotiable increments. Most ride are giant 200 mile rectangles with 4000-5000 feet of climbing. Over the last three years I've done these types of rides about 25 times, and they all range from 12 to 14 hours. The "real goal - is to always maintain ride speed average above 16.66.