Competitive athletes make the mistake of overtraining more often than undertraining. For some, it can be a matter of life or death.
Rich Stanfield had heart surgery in 2008 and is currently at risk for atrial fibrillation, a condition in which the heartbeat can rise rapidly to unsafe levels.
"We runners tend to push ourselves at the end of a race or a workout," says Stanfield, 65. "I think that's what ultimately led to my heart problems."
Under his cardiologist's guidance, the Phoenix resident continues to run and race, but he needs to keep his heart rate below a specific count. He's able to accomplish this with a heart-rate monitor: a flat, plastic device the shape of a silver dollar attached to an elastic strap that wraps around the chest. The monitor detects heart beats and transmits the count to a wristwatch.
"With heart monitors, you can actually set a chime on them. If you exceed a rate and if you're not staring at it, that chime can go off and let you know you're above where you want to be," explains Stanfield.
While most of us can feel when our heart rates are unusually high, that's not true of some cardiac patients.
"He's on medication to lower his heart rate," says Dr. Bruce Patterson, a Medford cardiologist who treats Stanfield. "So he can't always be aware of it (elevated heart rate) during exercise."
Patterson wants most patients to get off the couch and engage in moderate exercise. If they do insist on pushing themselves, says Patterson, "I want to make sure they're not getting into trouble. Heart-rate monitors can alert them when they're nearing the danger zone."
Heart monitors for athletes were originally developed in Finland to help cross-country skiers. They became an international consumer item in the late 1990s when a Finnish professor started the company Polar Electro. Those first Polar monitors were simple devices that displayed the heart rate in real time and not much more.
Today, those simple watch-and-strap systems can cost as little as $55. Some models contain Global Positioning System technology that indicates how fast you're going, your elevation and a map of your running or bicycling route. Many models allow you to upload a variety of recorded data to a computer or website. The fancy models easily can cost $300 to $400, but judging from their prevalence at local fitness clubs, where people wear them while pumping weights, riding stationary bikes, jogging on treadmills and pumping away on elliptical trainers, price doesn't seem to be much of a deterrent.
Ashland resident Charlie Carlson, who is part owner of University Bicycles in Boulder, Colo., says heart-rate monitors provide athletes with a way to gauge fitness.
"If they ride the same ride a year later with a lower heart rate, they're doing well," says Carlson.
As a person becomes more fit, his or her heart will become more efficient and it'll beat slower while running, biking, swimming or lifting weights than it used to. It'll also return to normal more quickly after finishing the exercise.
To improve fitness, many athletes work to keep their heart rate within a certain zone. To develop aerobic fitness, for instance, trainers recommend keeping the heart working at about 60 to 70 percent of a person's maximum heart rate, a number that varies by age, weight and fitness level. Go too far above that range, and other bodily systems will be stressed, which requires alternating days of rest so the body can recover sufficiently.
"What I realized was that we all ride too hard," says Carlson. "The heart-rate monitor showed you if you take it a little more easy over a longer period of time, you could maintain a more consistent heart rate and a more consistent, average speed over a long distance."
If you do overtrain, your resting heart rate rises and it takes more effort to maintain the same speed. A heart-rate monitor helps spot these trends.
To get the most out of a heart monitor, you first need to know your maximum heart rate, which helps you figure your target heart rate for various activities.
Maximum heart rate drops as we get older. Thirty-year-olds, for instance, can push their hearts a lot harder than 60-year-olds.
The standard method of determining maximum heart rate is to subtract your age from 220. A 30-year-old would have a maximum heart rate of 190 (220 minus 30), while a 60-year-old would have a maximum rate of 160 (220 minus 60).
The target heart rate is a percentage of the maximum heart rate. For people who want to work out in the "aerobic fitness zone," they'd want to keep their heart beating between 60 and 70 percent of maximum. For a 30-year-old, that target range would be 119 to 133 beats per minute. For a 60-year-old, that range would be 96 to 112.
This method is only a guideline, however, and a person's maximum heart rate can vary greatly from others of the same age depending on weight, fitness level, medical history and other factors. A treadmill test can help a person pinpoint the individual number more specifically.
Elite athletes commonly use heart rate, and heart-rate monitors, to fine-tune each training run.
"My training runs are either easy, recovery or interval runs," says Medford marathoner Liana Bernard. "I use my heart-rate monitor, so I know when I'm working too hard or not hard enough."
Bernard is currently ranked 62nd nationally among women marathoners who have qualified for the Olympic Trials marathon race next January. She uploads her daily workouts from her wristwatch to www.runningahead.com, which tracks her fitness over time.
"I can rate each workout day," says Bernard. "I'm a detailed person, so I write down how I feel, the weather, and I go back to old workouts to see how I'm progressing."
Most of us, says Carlson, won't make it to the Tour de France. Heart-rate monitors, however, can help motivate us.
"If putting on your chest strap is part of your morning routine, great," says Carlson. "Getting out and running or biking regularly is the important thing."