"Dehydration and heatstroke go hand in hand," says Peter Galier, MD, associate professor of medicine at the David Geffen School of Medicine at UCLA. "It happens most commonly in people who are out in the sun."
What happens, explains Galier, is that people sweat and replace their lost electrolyte-packed body fluids with only water. Dehydration can soon follow, and heatstroke can set in if a person becomes so dehydrated they can't sweat enough to cool down, and their body temperature rises.
How to avoid it. "If you are outside and sweating, you should be drinking at least a 50-50 mix of Gatorade and water, which has potassium and sodium," Galier tells WebMD. "You need to be drinking at least one small liter bottle of this mix every hour if you're working or exercising in the sun."
Warning signs. "Symptoms of dehydration can run the gamut from thirst and general fatigue, to headaches, nausea, and confusion," says Galier. "Heatstroke symptoms are also headache and confusion, but include delirium and even hallucinations."
What to do. While mild dehydration can be treated by rehydrating with fluids, heatstroke is more serious. "If you have heatstroke, you need to go to the emergency room so you can have intravenous fluids," says Galier. "With really bad heatstroke, your kidneys can shut down."
The old adage still rings true, explains Galier. "Leaves of three -- let them be," he says. So when the summer months begin, plan ahead when you know you're going to be trekking through the woods.
How to avoid it. "Poison ivy is a tri-leafed plant, usually with a little yellow and purple, and it tends to be anywhere with shrubbery, hiding out with other vegetation," says Galier. "So stay out of shrub areas or wear high boots or high socks, stay on the path, and don't touch anything you don't recognize."