Children over 10 and adults (including seniors) have 60 to 100 beats per minute for resting heart rate.
If the resting heart rate is to be determined, you must have been resting for at least 10 minutes before measuring.
Many things can cause changes in your normal heart rate, including your age, activity level, and the time of day.
Do you take some meds, like meds to treat asthma?
Are you taking stimulants such as caffeine, amphetamines, diet pills, and cigarettes?
Are you stressing and worrying over something?