Running can be friendly to all participants in view of its health benefits. Squeeze in a forty minute run five times a week to achieve a level of physical fitness and mental well-being. For those who seek a challenge, the length and intensity of daily runs can be increased to test one's athleticism. A stopwatch measures the quality of a run but requires harsh discipline; a heart rate monitor tracks the quality of effort-- it is an intimate, personal measure of the body's response to a workout. Most lifelong exercisers find satisfaction in the ability to achieve a regular training program; blazing speed is only required by those who emphasize competition. A heart rate monitor can be used at fifty percent (recreational) effort as well as at eighty percent (race training) effort.

Technological advances have made it possible to reliably measure heart rate during exercise at a cost affordable to most dedicated athletes. A precision instrument to monitor the heart can be purchased for less than $90; unlike a pair of good shoes, a heart rate monitor lasts far beyond 500 miles. A monitor enables one to obtain instantaneous feedback on the intensity of a run and use this information to adjust pace. The measurement is independent of distance so the workout can take place on any course.

A heart rate monitor provides motivation by increasing awareness- -running in a 'target zone' indicates that a good effort is being made. During a long (two hour) run, it helps focus one's attention on any decrease in pace. A monitor offers greater flexibility than a stopwatch-it can indicate the intensity of training anywhere, not only on a track, and allows one to make adjustments on the fly.

An athlete's capacity to deliver oxygen to muscles is key to successful training. Oxygen and carbohydrates are used for synthesis of the body's fuel, ATP. Muscles need ATP to produce work and move the body forward. The heart serves as an engine to deliver the necessary oxygen, which is transported in the bloodstream. There is a direct correlation between muscular activity and heart rate; as you run faster, your heart rate increases.

Two heart rate monitors were tested: an Acumen (www.acumeninc.com) Basix Plus ES, a lightweight women's model, and a Sigma Sport (www.sigmasport.com) PC 800, which includes a bicycle mount for multi-sport athletes. The Acumen monitor had an advantage of being small; the Sigma Sport monitor had the advantage of recording time spent below and above a chosen target zone. Both monitors have a digital display of heart beats per minute and also record the minutes spent inside a target (heart rate) zone.

Results
Effective training requires a focus on individual performance and an ability to filter out distractions. Both monitors proved reliable during a six month period of use; from the first use, this product added considerable enthusiasm to a workout. A watch on the wrist that displays heart rate allows easy viewing anytime during a run and keeps one alert to variations. A consistent range of heart rate readings-staying in a target heart rate zone-quantifies even pacing; an increased heart rate signifies an increased tempo. By following the monitor display, one can correct unintended changes in rhythm.

A heart rate monitor allows one to tinker and refine one's workout routine; on days when one feels ill or fatigued, an inability to raise heart rate provides an alert to cut short a workout and get some extra rest. The thrill of hitting stride on very good days and pumping up the numbers on the display for a few brief minutes is fun, a small dose of speed. Stopwatches are ideal for intervals, but a heart rate monitor works well for long runs-the pace is slower and the target zone is lower. As one adjusts intensity with the length of a run, satisfaction comes from the knowledge that one worked within a reasonable target. When a fast runner breezes by, don't despair. Look at how fast one's heart is beating and gracefully chase behind; accept that this good effort is slower but still valiant.