Shed U: Heart Rate 101

by Rachel on August 31, 2009

Gooood morning! I spent this past week and weekend doing a lot of studying for my upcoming exam (four weeks from today), and I actually feel like I am starting to learn quite interesting things! A lot of it is common sense (Warm up and cool down? Oh really??) but the more I get into it, the more I realize I didn’t know before. So since it’s back-to-school time, I thought I’d spend this week sharing some of the basics behind the major aspects of a fitness program. A lot of us work out without knowing what we should do or why we should do it, so hopefully this little series answers some of those questions and helps you find ways to get more out of your workout. So…welcome to Shed U!

And the first lesson is… heart rate! Since cardio makes up the bulk of “working out” for so many people, I figured I’d start there. But really understanding cardio means understanding heart rate–a term tossed around a lot, often without explanation. Here are some facts.

  • Heart rate is the number of times your heart beats per minute.
  • Resting heart rate can be measured by placing your fingertips on the artery in your neck, just to the side of your larynx. (Don’t push too hard.) Count the beats for 30 seconds and multiply by two, or just count for a full minute. It is most accurately measured first thing in the morning, before you get out of bed.
  • Maximal heart rate is the highest heart rate a person can obtain. A trainer can help you determine your max heart rate to get an accurate number.
  • If you don’t want to go that route, subtracting your age from 220 is the standard method for estimating max heart rate. But keep in mind it is only an estimate and can be off by as many as 10-12 beats per minute!
  • To get the most benefits out of cardio exercise, you need to be working out at the right intensity—and exercise “intensity” is very much dependent on your heart rate.
  • Optimal exercise intensity for health benefits and weight loss is about 60 to 90 percent of maximum heart rate. Therefore, you can find your target heart rate for exercise by multiplying your desired intensity (0.60 if it’s 60 percent, 0.85 if it’s 85 percent) by your max heart rate. Again, this method is prone to error, but it can give you a rough estimate. It’s good to have that range in mind—“I don’t want to go lower than X or higher than Y.”
  • So, using this method, a 21-year-old woman would roughly want to keep her heart rate between 120 and 180. This is a huge range! Where you fall on that scale seriously depends on your fitness level. Just because your upper level is 180 does not mean it should be. And just because 120 is “enough” does not mean it is going to challenge you. It might take some time experimenting to determine what heart rate in that range you can sustain for 30 minutes. When figuring this out, be conservative.
  • Once you have determined an appropriate target heart rate for exercise, you can monitor your heart rate during your workout to keep your intensity where it should be to hit your goals.
  • Many cardio machines come equipped with HR monitors. These are notoriously inaccurate! It is not worthwhile to use these! Grabbing the handles is just not going to do the trick—sorry.
  • A very accurate and easy way to monitor your heart rate is to use an electronic monitor. It contains a chest strap that picks up your heart rate and a wrist receiver that tells you what the number is. There are many on the market, at all different price points, with all sorts of bells and whistles. My little Timex cost $40 and I absolutely love it. (Read more about that here.) And when coupled with the HR monitor on the machines, they are accurate.
  • Not knowing what intensity/heart rate is right for you could lead to problems. Working out too hard will lead to burning out or injuring yourself, while working out at too low of an intensity could be why you aren’t seeing results or meeting your goals.
  • Intensity also affects the duration of your exercise. Working out at a lower intensity means you should be able to do it for longer; working out at a high intensity means you won’t be able to sustain it for as long.
  • A lot of times we feel like our workouts are more intense than they actually are! It could be very hot so we’re sweating a lot, or we could be huffing and puffing (we’ve all seen that guy at the gym), when in reality, our heart rates aren’t all that high and our workouts are not that intense. So monitoring it holds you accountable.
  • As you get in better shape, it will take more effort to reach your target heart rate. You might start a walking program, and, a month in, notice your heart rate is lower while walking at your standard speed. Time to pick up the pace!
  • Many things can affect your resting heart rate so it is not completely indicative of fitness; however, a decreased in resting heart rate usually comes with an improvement in cardiovascular fitness–so that’s a good thing. And a chronically elevated resting heart rate can be a sign of overtraining in a vigorous exerciser.

I hope that little lesson inspires you to get your heart rate up today!

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