If it’s as hot where you are as it is where I am with temps creeping up on the 100’s you need to take some precautions especially if you are cycling in this crap….which if you are as demented as I am you are. Stay safe out there folks.
Just a bit of advice from your friendly neighborhood fireman on how to excercise in the heat:
-Increase your fluid intake. By consuming hydrating liquids throughout the day, prior to, during the activity–every twenty minutes–and after exercising, you will prevent dehydration and regulate your body temperature. Dehydration is your worst enemy. If the weather is hotter or more humid than you’re acclimated to, drink more fluids, even if you aren’t thirsty.
-Adjust the schedule of your exercise regimen. The prime schedule for exercise is before 10 a.m. or after 3 p.m., especially if the temperature is rising and humidity is high.
-Refuel your muscles with nutritious foods. It’s just as important to monitor what you eat as to increase your fluid intake. Heat often decreases the appetite, but it’s imperative to consume plenty of fruits, vegetables and grains.
-Know when to quit. Pay attention to the warning signs of your body. If you begin to feel the effects of heat exhaustion, immediately cease your exercising and find somewhere to cool down.
-Avoid consumption of caffeinated beverages because they can cause dehydration due to their diuretic factor.
-Stay away from wearing darker colors and tight clothing that soak in the heat while exercising during summer.
Signs and Symptoms of Heat Stroke:
-Heatstroke is a condition that can occur when your body temperature raises above 104 degrees F. Often occurring in the extreme heat or when there is too much physical activity done in the heat, you should know the signs of heatstroke so that you can recognize it in yourself and others. It can be a potentially life threatening disease, and the faster that you treat it, the better your odds are that you’ll recover.
Sweating
Depending on the type of heatstroke that you have, you may notice a change in the way that you sweat. If your heatstroke was brought on by heat alone, then your skin will be hot and dry, with no sweat at all. If your heatstroke was brought on by physical activity, then your skin will be both hot and moist. You should sweat in the heat, but too much or too little sweat can be a sign of heatstroke.
Rapid Heartbeat
If you are afraid you might have heatstroke, take a moment to feel your pulse. A pulse of about 130 beats per minute is much too fast for the regular 60 to 100 beats per minute that an adult’s rate should be at. The elevated rate means your body is working so much harder to cool off.
Weakness
Look for signs of weakness, listlessness or unresponsiveness in someone who you think might have heatstroke. Heatstroke can cause a person to lose strength and feel tired. Their muscles might also be sore and cramped.
Neurological Signs
Those with severe heatstroke might suffer from seizures, fainting, lost consciousness or may become incoherent and unable to understand others when they are speaking. If this is the case, get the patient to a health care facility
100 Pounds Ago 
Great tips and precautions, Gene. I was cycling with a friend on the 4th of July (95 that afternoon). He came down with heat exhaustion at mile 52. He had been hydrating regularly, but I think he hadn’t eaten enough for the exercise we were doing. He’s a fireman/paramedic too, so he recognized the signs right away.
I didn’t hydrate nearly as much as he did, but was fine. I’ve always had a high stamina for heat, even when I was huge. It’s always good to be prepared, though, and to take careful steps on those high heat days.