Heart Monitor Training For Triathletes

Heart rate is a measure of exercise effort that triathletes use to pace their training and racing. As exertion and heart rate increase, physiological changes take place that affect your endurance capacity and how you feel. A heart rate monitor gives a triathlete a window into the body to control the physiological factors that affect endurance and speed. Training with heart rate monitoring is more objective and scientific than training on feel alone and more practical than training by pace.

Lactate Threshold

The most important heart-rate number for a triathlete is not his maximum heart rate but his lactate threshold (LT), the point at which muscles produce lactic acid, a byproduct of anaerobic metabolism, faster than the body can clear it. By knowing your heart rate at LT, you can race at your maximum possible effort without slowing down. Your average heart rate for an evenly paced 10-km time trial (biking or running) or 1,000-yard time trial (swimming) should be within a few beats of your real LT heart rate.

Improving Lactate Threshold

You can increase your heart rate at LT, and thus the speed you can maintain during a race, with training. To raise your LT, Joe Friel, author of "The Triathlete's Training Bible," suggests 1.5- to two-minute intervals at or above your LT heart rate. Rest periods should be 2.5 times longer than the LT interval. Your total time at or above LT shouldn't exceed 12 minutes per workout. Do "LT tolerance intervals" for each sport once a week, beginning ten weeks before your highest-priority race.

Heart Rate in the Three Disciplines

A triathlete's heart rate varies by sport. Swimming heart rates tend to be lowest and running the highest. Because heart rates differ between sports, define separate heart rate targets and do separate LT tests for swimming, biking and running using the heart monitor.

Recovery Heart Rate

Triathletes even exercise to recover from training. "Recovery workouts" clear lactic acid and other cellular waste from fatigued muscles and bring fresh oxygen and nutrients to mending muscles. However, for a recovery workout to be effective it must be so easy that it doesn't tax the recovering muscles. Your heart rate monitor is key to tempering your effort in recovery workouts. USA Triathlon coach Ken Johnson recommends using your heart monitor in order to keep your heart rate between 65 and 85 percent of your LT during recovery workouts.

Interpreting Heart Rate

Heart rate is a fickle number that changes in response to more than just exertion. Stress level, temperature, caffeine, diet, medications and other factors all affect your heart rate, so evaluate your effort based not only on your heart rate monitor but also how you feel. If you can't easily raise your heart rate and you feel sluggish, then it is a sign that your body is fatigued and needs to recover. Another cue that you need to recover is if your morning heart rate (taken before getting out of bed) is ten beats per minute higher than usual.