Runners, swimmers, cyclists and others who participate in long-distance sports have to be in top physical condition so their hearts can meet the extra demands placed on their bodies. Not only do months and years of training make the cardiovascular systems of these athletes work harder, such training promotes a more efficient heart rate. Elite competitors like cyclist Lance Armstrong can have a resting heart rate of 32 to 34 beats per minute, far below the average for non-athletes.
Your cardiovascular system delivers oxygen to your muscles, which they use as fuel. The harder you work, the more you overload your aerobic capacity and the more your body has to adapt at rest to make your heart stronger. Your heart rate is the number of times your heart beats per minute and is a measure of how hard and effectively your heart is working. A resting heart rate between 60 and 90 is considered normal, while the normal maximum heart rate during exercise ranges from 150 to 200.
If you’re sedentary, you can decrease your resting heart rate by one beat per minute per week during your initial endurance training, as more blood returns to your heart and leads to changes in autonomic nervous system control. You can decrease your heart rate while exercising by 10 to 30 beats per minute within six months, according to Mike Collins, cross-country coach at Lewis-Clark State College. Also, the more you train, the faster your heart rate will be able to recover following your workout.
The term "athlete's heart" refers to a group of changes, including bradycardia, or a slow pulse of less than 70 beats per minute, and phasic sinus arrhythmia, a pulse that speeds and slows as you breathe. Found in up to 69 percent of aerobically trained athletes, these conditions can cause a feeling of skipped beats. Dr. Luis Mont from the Hospital Clínic de Barcelona, Spain, adds that disturbances in heart rhythm, particularly atrial fibrillation, are more common among cyclists, marathon runners and other athletes with a long history of endurance training. Low resting heart rates, combined with large leg muscles and the tendency to be dehydrated, also make some athletes up to 85 percent more likely to suffer from deep-vein thrombosis, or blood clots.
Certain conditions such as altitude or excessive heat can affect heart rates during exercise, even among trained endurance athletes. Symptoms of heart-rate problems due to overtraining can be persistent heart palpitations, dizziness or nausea. If you have a personal or family history of heart disease, or if you’re male and over age 40 or female and over age 50, consult your doctor before beginning an endurance training program.