Final answer:
When athletes run up and down a football field, their bodies experience increased muscle activity, which demands more oxygen and results in deeper breathing. Excess heat from exercise is dissipated through dilation of skin blood vessels and sweating, with sweat evaporation cooling the body. Proper hydration and electrolyte replacement are essential to prevent overheating.
Step-by-step explanation:
During vigorous exercise, such as running up and down a football field, several things occur inside the body to result in heavy breathing and sweating.
- Muscle activity increases the demand for oxygen, leading to increased respiration to supply the necessary oxygen and to remove carbon dioxide produced by muscle cells.
- Thermoregulation: Exercise generates excess heat. This triggers the dilation of blood vessels in the skin, enhancing blood flow to the skin's surface, where heat can be released into the environment.
- Sweating: Sweat glands are activated to increase sweat production. As sweat evaporates from the skin, it takes heat with it, cooling the body down.
- The respiratory system responds by increasing the depth of respiration, and breathing may switch from nasal to oral to enhance heat dissipation from the lungs.
These responses are crucial in maintaining the balance of bodily fluids and preventing overheating, which can lead to heat-related illnesses. Athletes must replace the water and electrolytes lost during heavy sweating, as highlighted in the historical development of sports drinks like Gatorade.