A normal resting heart rate for adults ranges from 60 to 100 beats per minute. However, for most healthy adults, the range is between 55 and 85 beats per minute. Factors such as stress, anxiety, hormones, medication, and physical activity level can affect resting heart rate. Well-trained athletes can have resting heart rates in the 40s, but a heart rate that slow for the average person would be concerning and should prompt a call to a doctors office, especially if accompanied by weakness, lightheadedness, or shortness of breath. On the other hand, a resting heart rate consistently above 90 beats per minute should also be brought to a doctors attention, as it could be a clue of an underlying issue, although not necessarily a serious problem.