18 Things That Happen to Your Body When You Don't Drink Enough Water

If you're out in the sun, you'll be at risk of heat stroke

As heat illness progresses, heat stroke can occur. With heat stroke, Dr. Solti-Grasz says, the body tries to lower its internal temperature by systematically shutting down organs to protect the heart and brain.

Signs of Heat Stroke

• Low blood pressure – The body limits blood flow from extremities and redirects it to vital organs.
• Perspiration stops – When you stop sweating, your body has begun to shut down certain systems and functions to preserve life.
• Cold or clammy skin – As blood is redirected to vital organs, the skin becomes cooler.
• Shock – All of the above symptoms, signal shock, a life-threatening condition that occurs when the body enters survival mode. “Heat stroke is a grave condition,” he said. “Often people use this term interchangeably with heat exhaustion, but heat stroke can be fatal, so it’s important to focus on preventing dehydration first to avoid the progression to heat stroke.”