Michelle is sixty years old now. She hopes to calculate her body age to learn if she is living a healthy life. Here are her ways to calculate her body age:
Find resting pulse rate（静息脉率）
A healthy heart usually beats between 60 and 100times per minute. A lower pulse rate shows that our hearts are strong. Higher pulse rates mean that our hearts have to work harder to do the same amount of work--they are weaker.
She adds one year to her chronological age（实际年龄）because her resting pulse rate is more than 100 beats per minute.
Calculate sleep
Our body needs sleep. People usually need to sleep between 7 and 8 hours per night. Getting less than that can make us tired and older.
Michelle will subtract（减去）six months from her age if she often gets 7-9hours of sleep. If she gets 5-6 hours of sleep or sleeps more than 9 hours, she will ad one year to her age. If she gets less than 5 hours of sleep, it means her body age will be even older.
