Case Scenario: A 65-year-old man was hiking on a hot day. He was out about three hours in 100-degree temperature. His overall physical history is negative for disease, and he hikes frequently in this climate. After his hike, he headed home but had to stop and call 911. He became disoriented, tachycardic, and when reaching the hospital had a blood pressure of 90/50.Question: What do his symptoms tell you?