barometer of health; measure of good health
Used figuratively to describe something that indicates or reflects one's health status, such as a habit, symptom, or daily condition.
Weighing myself every morning is a barometer of my health.
The condition of your skin is said to be a barometer of your health.
Compound of 健康 (health) + の (possessive particle) + バロメーター (barometer, from English). The phrase is a modern figurative expression.