A normal resting heart rate for adults ranges from 60 to 100 beats per minute, explains Mayo Clinic. Patients experiencing bradycardia, a resting heart rate continually less than 60 beats per minute, or tachycardia, a resting heart rate continually exceeding 100 beats per minute, should consult their physicians.
A resting heart rate slightly lower than normal generally indicates that the heart is in better cardiovascular condition and functions more efficiently, notes Mayo Clinic. For example, an athlete might have a normal resting heart rate of about 40 beats a minute. Several factors can affect a normal heart rate, including a person's fitness and activity levels, body size and position, emotional state, and medications. Symptoms of an unhealthy low or high heart rate could include dizzy spells, fainting or difficulty breathing.