Women, You've Been Exercising Too Hard, Says Study

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By: , SparkPeople Blogger
7/7/2010 7:00 AM   :  75 comments   :  49,286 Views

When someone asks me whether X, Y or Z counts as "exercise" or "cardio," my first response is always, "Well, what does your heart rate tell you?"

Measuring your heart rate is an important action for every exerciser. It lets you know how hard you're working during cardio, as different heart-rate levels have different training and fitness benefits. It tells you whether your activity session really "counts" (too low of a heart rate doesn't provide the benefits of aerobic fitness, and heart rates that are too high can be problematic). It can even provide clues that you're overtraining or coming down with an illness (high heart rates at lower exertion levels can are a sign that something's not right).

There is a variety of ways to calculate your individual target heart rate for exercise. Getting tested at a university lab or medical center by way of a graded maximal exercise test is the gold standard, but since that's not accessible, safe or feasible for everyone, some standard formulas were created based on the available research at the time. However, a new study from Northwestern Medicine in Chicago says that the formulas experts have used for years to help people calculate their heart rates for exercise aren't accurate at all for women.

Researchers collected maximum heart rate date from approximately 5,500 healthy women between the ages of 35 and 93 during maximal graded exercise treadmill tests (the gold standard), and then followed the women for 16 years. While they were initially searching for a link between abnormal heart responses and heart attack risk, the researchers were able to use the data collected to generate a new formula for maximum heart rate in women.

It's no secret that a lot of the health, fitness and wellness information we have is based on research and that for a very long time, women were not even studied at all. We didn't know back then that you couldn't just apply the same results found in men to women, just as we didn't realize that different ages and racial and ethnic backgrounds could also alter the outcomes of research studies. The standard max heart rate formula (220 minus age) was based on generalizations from 10 studies done several years ago on men alone, but it's been applied to men and women of all ages for decades now.

I've always been somewhat skeptical of that generalized formula, since it assumes one's maximal heart rate declines with age and that one should work out less intensely with each year they celebrate another birthday. That doesn't make a lot of sense if you think about, and surely can't be the case for everyone. SparkPeople has always advocated the use of another formula that is touted among fitness professionals as being more accurate (although slightly more complex): the Karvonen heart rate formula. It's more accurate because it considers a person's resting heart rate (a good indicator of fitness level) when coming up with heart rate guidelines for exercise. The new formula developed by the Chicago researchers who conducted this study says that a women's max heart rate should be calculated as 206 minus 88% of a woman's age. That's not as easy to remember, but its results are said to be more accurate for women, according to these researchers. It also results in lower heart rate ranges for aerobic fitness benefits.

I wanted to conduct my own little experiment to see how the outcomes of all three of these heart rate formulas pan out, using myself (an almost 28-year-old) as the example.

  • Standard formula: MHR = 220-age = 220-28 = 192
    55%-85% target heart rate range = 106 – 163 beats per minute (bpm)
  • Karvonen formula: uses standard MHR formula (above), but also factors in resting heart rate
    55%-85% target heart rate range = 133 – 172 bpm
  • New women's formula: MHR = 206- (age *.88) = 206-25 = 181
    55%-85% target heart rate range = 100 – 154 bpm

While these ranges don't seem strikingly different at a glance, there is a large range between the lowest (100 bpm) and highest (175 bpm) numbers. Just a few beats per minute can feel like a major difference when you're exercising. You can see a large difference between my Karvonen results and the new formula, but keep in mind that the former also factors in my own resting heart rate level (about 60 bmp), so not every 28-year-old would have the same results.

Dr. Martha Gulati who led the study told the New York Times that, "There’s nothing wrong with achieving a higher heart rate with exercise, and if you can maintain that, it’s fine." She also said that some women might have had a hard time reaching the heart rates recommended by the standard formula—but perhaps they didn't need to! In my opinion, that makes exercise and achieving its benefits a little less daunting for beginners or people with physical challenges—no more frustration at working hard but not seeing your heart rate reach the recommended levels you were seeking based on a misapplied formula.

What this Means for You
Keep in mind that this is a single study, and while some are hailing it as the most accurate study to date of women's heart rates during exercise, I have not yet seen any official changes in recommendations from exercise organizations such as The American College of Sports Medicine. This study may change what fitness professionals recommend, but it's too early to jump to that conclusion yet. We'll wait and see if other exercise organizations change their recommendations before we alter our own.

What is interesting is that lower heart rates do seem to contribute to aerobic fitness benefits in women, if this study is any indication. That coincides with a growing body of research that says even low-intensity activity provides a multitude of health and fitness benefits, even if it doesn't push your heart rate sky high.

Just as the findings of one study on men can't always apply to women, the findings of this study may or may not apply to you. Put simply, these are averages based on the women in this study and they may not work for everyone. Heart rate formulas, calorie calculations, BMI—whatever the recommended levels are, they are still generalizations for the average population. We are all individuals and some of us may not fit into the standard. We are all an experiment of one, as Coach Nancy often says.

I've had many students in my classes ask me about their target heart rate ranges, some saying that they use these formulas but the results seem either too high or too low for them. My answer: You're probably right! I like to use a combo of formulas and RPE (Rate of Perceived Exertion) to help people achieve the proper exercise intensity, and that is exactly what the American Council on Exercise recommends as well. If your heart rate says you're working at 90% of your max (super intense!) but it feels like a walk in the park to you, then the formula probably isn't accurate—for you. Some people may have to tweak things here or there to find the right ranges for them. For women who have been trying your darndest to reach a specific heart rate level, but find it too tiring or impossible to get there, this newer formula, which results in lower heart rate ranges, might be a good one to try.

Personally, I'll stick with the Karvonen formula for now, but I won't discount low-intensity activity in my day as being useless. According to this formula at least, I'm working harder than I realized!

Do you measure your heart rate during exercise? What do you think about the results of this new study? Will it change how you exercise or how you calculate your own target heart rate?

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Comments

  • 75
    according to the new formula I was exceeding my maxHR when doing 4 min walking 1 min jogging intervals today! - 12/24/2013   7:26:24 AM
  • LILYOFVALEE
    74
    Does it matter what your fitness level is? I'm finding that it's harder to get my heart rate up the more I've been exercising. Or is it that you need to push yourself harder as you become more fit? - 9/27/2013   2:43:30 PM
  • 73
    Interesting article - I'll have to try it out . - 1/4/2011   7:26:34 PM
  • 72
    Comparing RPE to the formulas, the Karvonen calculation is fairly close for me. I stopped focusing on the actual numbers once I learned how to listen to my body. - 7/14/2010   2:46:39 PM
  • 1LUCKY1
    71
    Being active all my life, I have felt for years that the decreasing heart rate was wrong. My comfortable exercising heart rate is higher than the standard HMR formula recommends for my age. I have always used the perceived exertion as my guide. - 7/12/2010   10:31:13 AM
  • 70
    My resting heart rate is usually at 60-73 beats per minute. The doctor says that means he knows that I do lots of cardiovascular exercise. However, when I start to work out, it takes me a good 40 minutes to get my heart rate up to even 75% of my maximum heart rate. I try and I try. When I do manage to get it up there, like let's say if I run for a bit, then as soon as I stop, it will drop right back down from 153 beats per minute back down to 100 beats per minute just like that. Here is the formula that SP gave me:
    Results:
    Your heart rate ranges (in beats per minute) 55%: 132 bpm 75%: 153 bpm
    60%: 137 bpm 80%: 159 bpm
    65%: 143 bpm 85%: 164 bpm
    70%: 148 bpm
    So based on this formula, it looks like after 40 minutes of working out, I can finally get it up to between 70-80% of maximum heart rate, but if I continue to let's say walk for an hour, then even at that amount of time, my heart rate could be up to 75% and then drop drastically after I stop running. I don't know if this means I am in good shape or if I am doing something wrong? - 7/12/2010   9:51:24 AM
  • 69
    I do not follow the recommendations from any of these formulas because I don't break a sweat at the calculated heart rate ranges. I normally hit a heart rate of 170 b/m or higher (I am 56 and female), and it drops rapidly when I cool down. I think my resting heart rate is in the upper 60s but I have not had it measured. I know that when I first put on my HRM it has measured that level, so it is probably lower before I get out of bed.

    My husband's resting heart rate is in the upper 40s so getting his in the 120s is a major feat. We all have different bodies and I think the perceived exertion concept is a better way to go for many of us. - 7/11/2010   10:51:45 AM
  • LITTLEGIRLSMOM1
    68
    I can't go by my heart rate because of my walking disability but when I get to sweating and laboring to breath I know I am getting the workout I need. - 7/9/2010   9:57:28 PM
  • 67
    I'm on a beta blocker. I have not been able to get above a 120 BPM since being on it, no matter how hard I'm working. - 7/8/2010   9:45:10 PM
  • DRVILLEN
    66
    Yes I do, during an Insanity workout it stays around 155. - 7/8/2010   8:13:01 PM
  • NJ_HOU
    65
    I finally bought a HRM as my reward for another 10 lbs. gone. This article makes me feel better about the reward as a valid purchase - 7/8/2010   5:04:38 PM
  • 64
    If you are on blood pressure medication or beta blockers, I don't believe you can use these formulas either. - 7/8/2010   4:22:52 PM
  • 63
    I have my clients use RPE since our daily lives will add a variety of variables to our physical abilities on any given day. The amout of sleep, dietary intake, stress and with women where they are in their cycle can all have an impact on physical ability. We can high tech ourselves to the land of forever but in reality often the simplest solutions and measurements are the best. - 7/8/2010   12:48:59 PM
  • 62
    BLUEBRIT: Have you tried remedying the stress and anxiety to resolve your anorexia? Many times our symptoms are treated but never the problem of our symptoms. Maybe researching meditation or stress relief may help you? I know it's not completely relevant but there is a book called "Happy for No Reason" that I always suggest to anyone regardless of their situation. It's a starter to help us with anything in life, in my opinion. :o) - 7/8/2010   12:39:52 PM
  • BLUEBRIT
    61
    I have anorexia due to stress and anxiety. I am not allowed to exercise as obviously, this burns the calories that I NEED to gain. Having said that, I've been babysitting my grandson nearly every day because my daughter has Carbon Monoxcide Poisoning from an accident at work so obviously, the calories are just burning off as fast as I put them on. I so desperately want to do 'regular' exercise because even though my body has dropped over a 100lbs in a year+, from lack of exercise, my tummy is soft, arms a bit droopy at top. The rest is just skin and bone. This is so frustrating for me as I used to be a 'hard body' and now I'm just a 'skinny blob'. - 7/8/2010   12:19:38 PM
  • 60
    I like to use my HR monitor, especially during spin class. It keeps me motivated but also alerts me if I'm overdoing it. I calculated my heart rate for both methods and it looks like I've been pretty much staying in range. - 7/8/2010   11:16:19 AM
  • 59
    I'm on beta blockers due to a heart attack and so my resting HR is around 55. The formulas don't work for me so I've just been using the RPE. It seems to be the best indicator. My recovery time has gotten shorter which (I think) means I'm getting stronger. - 7/8/2010   9:59:46 AM
  • 58
    Another case of judging women's physical capabilities by men's standards, and yet another case proving that we are VASTLY different in more than simply physical appearance. No, I'm not a feminist, but I AM sick and tired of trying to fit into a cookie-cutter that some scientist decided was right for me.

    Listen to your body, stop when it hurts or starts to feel "weird", and enjoy your exercise! Is there any other "forumla" required?

    Just my two cents' worth. - 7/8/2010   9:42:49 AM
  • RLMCCUE
    57
    I just recently bought a heart rate monitor and have been using it during different types of workouts to see where I am. I am concerned that my MHR seems to be really high when my RPE doesn't exactly match, but I'm still a beginning exerciser and haven't used the HRM for very long. Thanks for the information! - 7/8/2010   9:19:43 AM
  • 56
    I have tried several devices to keep track of my target heart rate when I exercise. When all is said and done, I think I do best when I pay attention to how I feel when I exercise. Perhaps I don't push myself as much as I could, but if I am sweating, breathing hard (but able to talk in short phrases), and feeling good, then I figure my heart is going at a good pace. - 7/8/2010   8:57:24 AM
  • 55
    I have used an HRM in past to track my heart during exercise. After a while, I found it cumbersome. So, I started using rate of perceived exertion instead. I could get some pretty wild readings from my HRM. RPE seems a bit more accurate. I do still occasionally use my HRM when I'm training.

    Do women push themselves ? Definitely. We've been spoon fed the notion of "no pain, no gain". Well, strange as this may sound, but a person doesn't have to kill themselves to be healthy. I've been reading studies that have shown that doing too much intense exercise could be detrimental to our long term health. Interesting, huh ?

    - 7/8/2010   8:52:20 AM
  • 54
    This is surprising, but when I think about it, not so very.
    We are so hard on ourselves! - 7/8/2010   8:28:19 AM
  • BIJOUX7
    53
    This challenges everything I've learned! But as one poster commented for so long women were treated as small versions of men in research studies. I use a hrm when I run- because until reading this article I thought I was not working hard enough. I'll use the new formula- what I thought wasn't hard enough was really just right. - 7/8/2010   8:26:18 AM
  • 52
    The rules, formulas and information keep changing and that is why i gauge how i feel. if it is too much for me, i slow down. if it feels too easy i work harder. i push through my old limits to find new ones. but common sense is the key. if your body screams pain, if your heart is beating so fast and you are gaspiing for breath - for goodness sake, stop and take stock. i have seen people exercise themselves to a heart attack or pass out. that's just crazy. BB - 7/8/2010   7:30:46 AM
  • LAPPELSON
    51
    I have started wearing a HRM only when running but never look at it because I find that it holds me back if the number is too high. Today I had an awesome run, 5km with negative splits each km, each kilometer faster than the previous one. By the end it was super hard but the problem was definitely more mental than physical and I forced myself and was able to finish with no problems. Afterwards, I looked at my %HRM and the highest percent it got to was 107%. If I had seen that number earlier, I probably would have stopped. My resting HR is 47 and after stopping, my HR drops pretty fast.
    I totally agree with the statement "everyone is an experiment of one" and it was a conversation that I had with my trainer today (after the run!). Although interestingly enough, he didn't agree with me. - 7/8/2010   7:26:58 AM
  • 50
    For too long women have been considered the same as men when it comes to medical things. Studies used to be conducted just using men because women had hormonal issues so they could not take part in the study. I am more pleased by the fact that things are just being done with and for women, it is way over due. - 7/8/2010   7:20:45 AM
  • 49
    Interesting article - but for me, a 42 year old woman, I should have a max rate of 169 and 55%-85% is 92 - 143?? Hmmm.... that seems, for me at least, to be really low. I think I just have a faster HR than average, or I can handle working harder. For now I will use HR to track calories and RPE to determine intensity, but it's true, and I agree, that every person is going to be different and this may really help and encourage women to get more active! - 7/8/2010   6:57:43 AM
  • RHYNIC
    48
    I sometime do keep track of heart rate, but for me if I am working out as hard as I can and I am not hitting the suggested target, then I know that traget was wrong for me and i don't give it another thought. Guide lines are great, but that is all they are for me. - 7/8/2010   6:17:42 AM
  • 47
    I found the article interesting, but have always had a high heart rate as long as I can remember. According to the charts at Curves I am way over, but never feel like I am working that hard, and have also been told that being Hypothyroid on medications can also affect these numbers. So with out medications it was always on the high side, and still is but have never felt anything negative from this. - 7/8/2010   5:34:04 AM
  • 46
    I don't measure my heart rate and never have. I have exercised all of my life and I just do what is comfortable for my body and heart. I'm 62 and have survived myself so far. lol. I don't take any medication at all and, as far as I know, am in excellent health. My blood pressure, cholesterol, etc are all good. It's interesting that people pay such close attention and I think, if I had heart problems, I might. I just don't do anything that hurts and I push myself as far as I think works for me. Thanks so much for the input. Mary Ann - 7/8/2010   4:33:44 AM
  • _MAOMAO_
    45
    Nicole, thank you thank you thank you! That makes so much sense. It certainly fits my experience. I think the usual MHR's are much too high. Fortunately, I had a couple jogging teachers explain that working at 60% of MHR does just as much good as 85% - it just takes longer. Over the years, knowing that took a lot of pressure off. I'm SO glad to see this study! - 7/8/2010   3:14:58 AM
  • 44
    My resting heart rate (65) seems very low for my age (66) weight (111kg) and fitness level (poor) and when I exercise it often hits red on my HRM - going to 130 odd!!
    However the HRM is probably calculating everything as "average and my abismally low BRM is probably a factor in all this too!! I ease off then - however - doesn't really matter what it reads or what the daily calorie recommendation is - I don't see those scales taking interest!!
    What it adds up to is that everything is mearly a guide - not necessarily the thing that will work!!
    - 7/8/2010   1:29:04 AM
  • 43
    Funny that this article is here now. I have been wondering about heart rates. I have two heart rate monitors. One on my bike computer that I use when cycling and then one I wear to my other classes at the gym and other activities. It's nice because I can see when I need to push myself a little harder to get the calorie burn. Since I started exercising consistently in February my resting heart rate has come down really low, at least I think it's really low. I have a resting heart rate of 48. It takes a lot for me to get my heart rate up now and can be frustrating at times. It's caused my daily calorie burn to be much lower. I do have to say though that my endurance and overall health is a lot better now , so I guess that's better in the long run. I'm curious to calculate all three ways and see where I stand. Thanks for the great information. Very timely for me! - 7/8/2010   1:23:29 AM
  • SOCALDEBBIE
    42
    We're also learning that heart disease presents itself differently in women than in men, and is harder to detect. Glad this is getting some attention. - 7/8/2010   1:17:51 AM
  • 41
    My resting heart rate is so low it is hard for me to keep it in my target heart rate zone when I'm working out. I wear my heart rate monitor, but the second I slow down and start my cool down, my heart rate drops from about 140-160 to 80ish.

    I don't know if that means I'm just in good shape or just need to work out harder!

    - 7/7/2010   11:40:33 PM
  • 40
    No I don't measure my heart rate. I have one on my pedometer but don't use it.
    Good info. - 7/7/2010   11:31:17 PM
  • 39
    Interesting info - 7/7/2010   11:26:45 PM
  • 38
    I do not consider heart rate during exercise I only considerPRE because when I have had treadmill tests my pulse goes down during exercise. My Mom is the same way. So it must be something hereditary. - 7/7/2010   11:04:45 PM
  • VERNICEMAZ
    37
    Yes, I definately will consider my heart rate when exercising from now on. - 7/7/2010   9:48:27 PM
  • 36
    I have a pacemaker, so heart rate isn't real useful for me--I use RPE. It's an interesting article, though. - 7/7/2010   9:34:03 PM
  • 35
    Thanks for the article - now I have to talk with my cardiologist about these meds. - 7/7/2010   9:03:05 PM
  • 34
    This is a useful and informative topic. I have a heart rate monitor (a Garmin with a strap I use sometimes, and a strapless HRM watch that I wear most of the time), and I like to see how I'm doing. During periods when I am not losing much weight, I can still get some satisfaction from monitoring improvements in fitness, and the fact that I have to move faster now (or carry more weights) to elevate my heart rate. I have had to carry weights for a while because of a succession of foot problems. I report, happily, that my seemingly chronic foot problems went away after I started wearing Skechers Shape Ups - at my doctor's suggestion, after he had a similar experience with his foot problems. So now I can start to pick up speed again, if I can just shake off the mental doldrums induced by too much work, a succession of orthopedic problems, and too little exercise.

    I'm 53. My resting heart rate is in the high 60s, and I work out most comfortably at heart rates below 160. 135, the recommended level for my age under the standard formula, seems too easy. When I ran a few races last year, I deliberately set out to keep my heart rate under 160, and I was able to finish.

    Here's a question for you: biking doesn't seem to elevate my heart rate as much as running, even when I try to go all out. Have you found that to be true as well?

    Good blog! - 7/7/2010   7:28:23 PM
  • SUNSET09
    33
    I don't monitor my heart rate unless I'm in a class that takes the time to do it. I know how hard I need to work out for the results I'm looking for. When my heart rate is up, I feel I'm getting the most from my exercise. Actually yoga doesn't seem like exercising however, I've seen and felt the results! - 7/7/2010   7:04:30 PM
  • 32
    Exercising is supposed to be hard. I don't have a heart rate monitor. I know if I can't talk but I can keep up the same pace, I'm in the right intensity.

    Besides, if women exercise that hard as the study says, then why is there so many overweight ones? - 7/7/2010   3:24:16 PM
  • 31
    Finding mine saved me a liver biopsy a couple years back. I was overtraining with my running 7 days a week and doing it for 70+ minutes each day always in my max heart rate for the majority of it and really didn't think anything of it. Then when my liver enzymes came back slitely high a couple of times I looked into it. I went and had a professional testing of my VO2 rating and my target heartrate zones. This cut my workouts down to 5 days a week and with my first heartrate monitor I kept myself in check better and got my liver back in line. - 7/7/2010   2:31:40 PM
  • 30
    I don't rely on the pulse rate monitors on the various cardio machines for accuracy. I know when I'm working hard and beginning to sweat and when it's too much or I'm getting tired. I check my own carotid pulse from time to time, though, just to see where I'm at. - 7/7/2010   2:02:17 PM
  • 29
    Very interesting! I have always doubted that any of these formulas were very accurate for me. I also doubt that this new one is. It's not uncommon for me to hold a heart rate of 180-190 bpm for a couple miles of running (it's no walk in the park of course but I'm totally not at or near my max if I can sustain that for 20+ minutes) and according to any of these formulas, especially this new one, that would be way way way higher than I SHOULD be working out. I'm feeling like the workout is pretty comfortable at about 160-170bpm. I would LOVE to go get tested to find out for sure! - 7/7/2010   1:53:48 PM
  • CE1966
    28
    I have never fit any of the formulas. I'm a 44 yo female, and it's not unusual for my heart rate to peak at about 185 and average in the mid 160's on a medium/hard run. My last hard 5K effort pushed it to 206. That's been the case for several years....through lots of running and working out, and I haven't seen a lot of "improvement" in it. Not sure what my true resting HR is, but I've seen it in the low 70's. My husband on the other hand hardly ever works out and has a resting HR in the 50's, and doesn't see the big jumps I do when he does work out. I think we are just all different and no formula is ever going to tell the story. - 7/7/2010   1:35:52 PM
  • 27
    I wear a touch HRM during my workouts and had no idea what to expect in the beginning. I've been using it for over 7 months now and have learned what areas I need to be in for myself. The formulas might be a good estimate but I think the best plan is to figure out what works for you (And if you are monitoring your heart rate, you can do that by using your own HRM!). I check my HR throughout my workout and make a mental note of the number on the monitor and my level of perceived exertion. With those two things, I now know where I should be during a workout and if I'm pushing hard enough, too hard, or if I'm slacking off! Its a useful tool but like you said, the formulas aren't for everyone! - 7/7/2010   1:33:29 PM
  • 26
    Although I try the BMI formula many times, good old fashioned persistence and instinct do it for me in the end. - 7/7/2010   1:19:09 PM

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