Factors that affect HR besides exercise

Chasing after a two year old, almost getting run over by a train or having to engage in any form of public speaking generally will affect your heart rate. And you don't need to strap on a heart rate monitor to see the change-you can feel it.

Sudden exertions and emotions aside, though, knowing what your heart is doing, even if you can't feel the changes, can be helpful, whether you're training for a marathon or trying to shed a few pounds. Wearing a heart rate monitor when you exercise "Is much more scientific," said Judy Kieres-McCormick, a certified strength and conditioning specialist and program coordinator at the Dundee Township Park District. "It's not just how you feel, but how your body's responding" to factors such as hydration, stress, the weather or even if you're coming down with a cold.

Knowing ahead of time if your heart rate is a little higher for some reason can help you find tune your workout, noted Allison Huntley, a certified personal trainer and program director at the Lake County Family YMCA.

"If you're already higher when you start exercising, you should still work within your target heart rate (typically 60 to 85 percent of your maximum heart rate)," she said. So while perceived exertion-how you're feeling-is important, a heart rate monitor can "show someone right where they're supposed to be and that they're doing things properly."

Factors that will raise your heart rate include:

Fatigue: Lack of sleep or a high intensity workout or event the day before will raise your resting heart rate.
Heat and/or dehydration: As you perspire, if you're not replenishing fluids, your blood volume drops, meaning there's less water in your blood, Kieres-McCormick said, "so your heart has to work harder to circulate the same amount of blood through the body." Later in your workout, you might see your heart rate increasing even though you don't feel like you're working any harder. That's a good sign to take a drink, she added.
Humidity: The most efficient ways to lose heat is through evaporating perspiration, but on humid days, your sweat doesn't evaporate, so your heart works harder to cool the body through other methods. You should slow down or adjust your intensity accordingly on humid days.
Stress: Whether you've had a hard day or you're nervous before a big race, "when you combine two types of stress (emotional and physical), it's too much for the body, and you're heart rate's a great way to indicate that. If it's a little higher, then you don't have to work out as hard."
Your health. If you're coming down with something, even if you don't feel sick yet, you'll probably see it in your heart rate, Kieres-McCormick said. "If the session feels a lot harder than your heart rate is telling you-if you can't get it up to your training level, it could be an indication that you're getting sick or overtraining. The same holds true if you don't feel like you're doing much but your heart rate shoots up," she said, "you could be overtraining or fatigued."
© Copyright 1994 Paula Lauer