I'd say trustworthiness, your friend is trusting you with keeping a secret that he or she will only share with you. I hope this helps :)
Answer:
You can calculate your maximum heart rate by subtracting your age from 220. For example, if you're 45 years old, subtract 45 from 220 to get a maximum heart rate of 175. This is the average maximum number of times your heart should beat per minute during exercise. Find the best one that supports this and don't forget to give me a heart.
As a person ages their cardiovascular fitness tends to DECLINE.
