A power control system includes an activity measurement apparatus configured to measure an amount of activity, a healthcare instrument configured to measure metabolic data, and a power instruction apparatus including a healthcare processing unit configured to acquire these pieces of measurement data. The power instruction apparatus includes an environment detection unit configured to detect ambient environment of each of the activity measurement apparatus and the healthcare instrument. The power instruction apparatus is configured to store, in its internal memory, the measurement data acquired from each of the healthcare instrument and the activity measurement apparatus, display the measurement data on its display screen, measure, with the environment detection unit, the ambient environment of each of the activity measurement apparatus and the healthcare instrument, determine environment suitability based on the measurement data, and display determination result on a display device to notify an occupant of the result.