Final answer:
Intensity of physical activities like running or cycling can be measured in terms of power, expressed in watts, which is the rate at which energy is expended. Calculations using body mass, efficiency, and workout parameters like stairs climbed per minute can be used to determine changes in body temperature or energy expenditure during exercise.
Step-by-step explanation:
Intensity can be expressed as an absolute workload, such as running speed and grade, or as a power setting on a cycle ergometer, by using the power output of an activity. Power is measured in watts and is a product of force and velocity. It is indicative of the energy being expended per unit time. For example, if cycling at a moderate speed is said to use 400 W, this refers to the power output or intensity of that activity. Workout intensity is related to how quickly energy is used, and for structured physical exercises, accurately measuring intensity can help tailor workouts to individual fitness levels and goals.
In physics problems, such as in exercise physiology, we often calculate the power based on known variables such as the number of stairs climbed per minute, body mass, and efficiency. This allows us to determine how long it would take for an individual's body temperature to rise or how much energy is expended during a workout. For example, a workout on a Stairmaster producing power equivalent to climbing 116 stairs per minute by a person weighing 76.0 kg with a 20% efficiency can be used to calculate the time taken for the body temperature to increase by 1.00°C.