Final answer:
Chemical energy from food is converted into kinetic and thermal energy during exercise. Muscle cells transform this energy, enabling physical activity, while excess energy is released as heat to maintain body temperature.
Step-by-step explanation:
Chemical energy is crucial during exercise as humans are biological energy converters. When we exercise, the chemical energy stored in food is transformed into kinetic energy for movement and thermal energy, which appears as heat. Our metabolism breaks down nutrients such as carbohydrates, fats, and proteins from foods, like those found in an energy bar, into simpler molecules. These are then transported to muscle cells, releasing energy to power muscle contractions. It is through this process that we are able to perform physical activities.
An individual's metabolic rate dictates the efficiency of converting chemical energy into mechanical work and heat. Typically, 20-25% of the energy is used for physical work, while the rest is released as heat, which helps maintain our body temperature.
Chemical reactions such as the catabolism of foods during digestion are essential for this energy transfer. These reactions break down food into molecules that act as fuel, releasing chemical energy that the body can use. Exergonic reactions, like those during exercise, produce more energy than they consume while endergonic reactions require an input of energy. However, both types of reactions are pivotal for maintaining the body's energy balance.