Final answer:
For BMR measurement, an individual must be awake and resting in a fasting state 10-12 hours after the last meal, which ensures that the test results are not affected by food or physical activity.
Step-by-step explanation:
The condition that an individual must be in for basal metabolic rate (BMR) measurement is that they must be 'awake and resting in a fasting state'. BMR is the energy released when the subject is at complete mental and physical rest, in a room with comfortable temperature and humidity, awake, and sitting in a reclining position, 10-12 hours after the last meal. It is the minimum energy required to maintain vital functions such as heart rate, respiration, and kidney function. By ensuring the individual is fasting and at rest, the measurement can be conducted without the influence of recent food intake or physical activity, which can affect metabolic rate.