GLOSSARY

Physical Activity Level (PAL) Table

Adult activity categories in the 2023 DRI energy framework; PAL is total expenditure divided by basal expenditure, not a label for one workout.

Physical Activity Level (PAL) usually expresses total daily expenditure relative to basal expenditure. It summarizes the activity level of a whole day rather than the intensity of one session.

Physical activity varies in intensity, duration and frequency. A hard training session may coexist with little movement during the rest of the day, and people can change nonexercise activity when training or food intake changes. A device's calorie estimate is not a direct measurement of total daily expenditure. Record the activity context and assess intake, recovery and longer-term body-mass trends together before changing a nutrition plan in response to one reported exercise value.

MET values describe an activity's energy demand relative to a reference resting rate. Standard MET tables are useful for comparing or classifying activities, but the reference may differ from an individual's actual resting metabolism. Multiplying a MET value by duration produces a volume indicator, not a direct measurement of energy expenditure in every athlete. Mechanical efficiency, body size, fitness and conditions can alter actual cost, particularly when values are transferred between different sports or individuals.

For example, adding a running session can be accompanied by less walking later in the day. The added session's expenditure therefore need not equal the increase in the day's total. Comparing movement patterns, appetite and recovery helps explain why an expected body-mass change does not follow a simple exercise-calorie prediction.