How do muscles contribute to thermoregulation in the human body?

What happens in the integumentary system of a person who is overheating?

Explain what happens to dermal blood vessels when heat needs to be conserved (i.e., due to a cold environment).

You are working in the emergency department when paramedics rush in with an unconscious patient. You notice that the patient is wearing athletic clothing and the skin on his face and elsewhere on his body is bright red. The paramedics tell you that he was picked up after collapsing during a bike race. What does the color of the patient's skin tell you about the probable cause of his illness? Explain.