A normal pulse for a person at full rest should range from 60 to 100 beats per minute, according to the American Heart Association. However, a lower heart rate is not necessarily indicative of an illness or threatening condition.
The American Heart Association reports that a pulse rate lower than 60 beats per minute is common in athletes or people who are physically active, as well as people who are taking a beta blocker or similar medication. Other factors that can affect heart rate include air temperature, body position and body size. Obese adults can have higher resting rates, but still do not normally exceed 100 beats per minute. Fast heart rates, known in medical terminology as tachycardia, can be caused by numerous factors, including fatigue, anxiety or excessive smoking, alcohol or caffeine intake.