Medications belonging to the group of beta blockers (e.g. atenolol, metoprolol) and some medications belonging to the group of calcium channel blockers (e.g. diltiazem, verapamil), can reduce resting heart rate. A resting heart of 50/minute alone is not a reason for worry. If you have symptoms like light headedness, greying of vision or fainting of episodes, your doctor may want to reduce the dose of these medications or substitute another for control of your blood pressure. Normal heart rate for an adult is in the range of 60-100/minute. It can go down in sleep and go up with exercise and stress.