Metabolic Equivalents, or METs, provide a straightforward method to quantify the energy cost associated with various physical activities. This physiological measure expresses the energy expenditure of an activity in relation to the resting metabolic rate. By standardizing how activity is measured, METs offer a consistent framework for understanding the demands placed on the body during movement.
What Are Metabolic Equivalents (METs)?
One Metabolic Equivalent (MET) represents the energy expended while an individual is sitting quietly at rest. This baseline is defined as an oxygen uptake of approximately 3.5 milliliters per kilogram of body weight per minute (mL/kg/min). This specific value serves as a universal reference point for assessing the energy demands of all other physical activities.
When an activity has a MET value higher than one, it indicates that the body is expending energy at a rate multiple times greater than its resting state. For instance, an activity with a MET value of 4 signifies that the body is expending four times the energy it would at rest.
Measuring Activity Intensity with METs
MET values provide a clear way to categorize the intensity of physical activities. Activities are classified into light, moderate, and vigorous intensity based on their MET values. Light intensity activities have MET values less than 3, such as walking slowly or light gardening.
Moderate intensity activities fall within the range of 3 to 6 METs, encompassing brisk walking at 3-4 miles per hour or general calisthenics. Vigorous intensity activities are those with MET values greater than 6, including jogging, running, or competitive sports. Understanding these intensity categories is beneficial for meeting recommended physical activity guidelines and working towards personal fitness objectives.
Calculating Energy Expenditure with METs
METs are also used to estimate the total energy expenditure for a specific activity performed over a given duration. The calculation involves a straightforward formula: Calories Burned = METs × Body Weight (kg) × Duration (hours).
For example, if someone weighs 70 kg and performs an activity with a MET value of 5 for one hour, they would burn approximately 350 calories (5 METs 70 kg 1 hour). The practical application of this method extends to tracking fitness progress, managing weight, and gaining a clearer understanding of the energy demands of various workouts.
Common Activities and Their MET Values
Many common activities have established MET values. For instance, sleeping has a MET value of 0.9, while watching television is approximately 1 MET. Light household chores like folding laundry are around 2.3 METs, and general cleaning like sweeping can be 3.5 METs.
More active pursuits demonstrate higher MET values. Brisk walking at 4 mph is about 5 METs. Cycling at a moderate effort (12-14 mph) is 8 METs, and swimming leisurely is around 6 METs. Vigorous activities such as jumping rope can have a MET value of 12.3. These values are averages and can vary based on individual effort, skill level, and environmental factors.