FF10: Heart Rate Monitors (summer 2011)

 

Heart Rate Monitors for Recreational Athletes

    Keeping one’s motivation cranked up is key for anyone committed to their fitness and using a heart rate monitor was an effective motivational device for both of us in 2011. Our very basic $40 model provided enough information to spur us on though one can easily spend $400 on a more sophisticated device.

    Based on our early experiences, I recommend using a monitor even if you are like us and have no interest in uploading the data to your computer and charting your workout results to attain peak athletic performance. Even casual, intermittent use of our simple monitor provided enough information to immediately increase the effectiveness of our training.


Establishing Your Maximum Heart Rate

    It doesn’t take dipping deep into the pool of fitness information to understand that you just gotta know what your maximum heart rate is to optimize your workouts. Once you know your maximum heart rate, then you can nod knowingly when your instructor (real or DVD) asks you “Are you in your zone? If you are/aren’t then you need to.....” Knowing your max lets you establish those all-important training zones to make the best use of your exercise time. But establishing your maximum isn’t easy to do.

 
  It was in fact curiosity about my maximum heart rate (MHR) that spurred me to buy a monitor. I was enjoying trotting up hills at the end of mountain hikes late in 2010 and started checking my heart rate by counting my pulse when I was pooped. I was also trying to catch a MHR when biking up passes at the moment that I was about to pass-out. But I knew, especially when on the bike, that I was losing precious seconds getting organized to count my pulse and decided that I needed a monitor to nab that elusive number. I’d calculated a maximum of 160 beats/minute several times from feeling my pulse so assumed that it was at least 170, maybe higher.

    There are numerous formulas based on your age to estimate your MHR, all of which put mine in the 151-167 beats/minute range, with the most frequently quoted formula (220 - your age) setting my MHR at 160. I was sure that my rate was higher than any of those estimates and since your all-important “zones” are calculated from the MHR, I longed to establish a better number by using a monitor. The wildly expensive alternative to the DIY approach with a monitor is obtaining a Cardiac Stress Test but for $40 we could both establish our max with the monitor. But if you have any doubt about your heart’s stability when pushing to the limit, better to stress yourself surrounded by medical professionals in a clinical setting.

    I am still strategizing as to how I am going to catch the most accurate MHR for myself, but have clocked it as high as 175 beats/minute using the monitor. I registered that reading on a favorite steep trail in the Dolomites--one of the places I had envisioned catching a peak reading. But after my second attempt, I decided that it was too demanding of a situation. I was pushing at the end of a 45 minute hike of over 2000’ elevation gain which ended at over 6,000’. I was fighting unstable footing, altitude, and fatigue on this trail so will continue looking for a better place to capture my max though in the meantime I’m using 175 to calculate my zones.

    Our best guess based on our early attempts at establishing our MHRs is that one needs to warm-up at least 10 minutes at moderate effort. Once warmed-up, you would ideally begin fast walking or jogging up an incline at low altitude and with good footing, like on asphalt. After a few minutes of this increased effort, during which you are watching your HR steadily increase on the monitor, you’d either move onto a steeper grade or move at a faster clip until you couldn’t raise your HR any higher. Running up a hill and jogging down several times might do the trick too. I’m guessing that I might hit 180 under those conditions. I’ve read online that treadmill MHR’s tend to be about 5 beats/minute higher than those measured when cycling but I hope to establish my personal max in both modes.


What To Do With Your Numbers In The Meantime?

    We’ve been fiddling for months trying to establish our MHRs, with much of that time passing while we look for the right outdoor circumstances when we are injury free. And now it looks like we’ll have to wait until we are out of the mountains and are at lower altitudes to get an accurate reading. But unsuccessfully stalking our MHRs hasn’t meant a lack of learning or improvement in conditioning.

    A surprising piece of information Bill gleaned from monitoring his HR when exerting is that he has a set-point beyond which it is hard for him to push his HR higher. At the half hour point of an Alps mountain hike, pushing hard had him gasping and feeling overwhelmed at a HR in the 120’s even though he had recently clocked himself at 169 beats/minute. He is learning that this limit that feels very real is on some level bogus because when he pushes again he can easily work in the 130’s to 140’s. He’s in the process of learning how to remove this apparent gatekeeper in his exertion so he can readily workout in more effective training zones.

    In contrast, I learned early in my heart rate monitor experiences that my body’s response to exertion is very different from his. My heart’s response to exercise intensity is very linear and my body sensations tightly correlate with my heart rate. And I’ve seen that I can push my HR up to high levels relatively quickly. I’ve only logged averages for a few sustained workouts but I averaged 150 beats/minute during a 45 minute workout on a steep trail in which I was attempting to establish a high average. On a 2 hour segment of a long riding day, I averaged 133, and that included standing around time for snacks and rests. On hard hiking trails, I quickly move into the low 140‘s and can bomb along at that level for long spells without being bothered with a set-point barrier like Bill has.

    Bill and I have gotten very different messages from our preliminary monitoring. Bill’s take-home message is that he needs to push harder to get his HR up higher earlier and keep it there. My message is that I’ve underestimated my exercise intensity and that I can already hold my HR in effective training zones without much prodding. We are suspicious that these differences between us in part explain why on long exertion days I have greater endurance--I tend to finish stronger in the last hours even though he may have ridden faster earlier in the day.


Resting Heart Rate

    In addition to establishing your maximum heart rate, the other number to know is your resting heart rate. Until recently, I didn’t pay too much addition to this number because one of its main uses is in establishing if you have over trained and I assumed that my lack of competitive zeal would protect me from over training. And a proper resting heart rate is taken lying down, and that seemed like a tedious chore to me.

    But upon further reading recently, I learned that the most accurate calculation of your training zones requires establishing your resting heart rate. Using a monitor or counting your pulse before you get out of bed in the morning is the best time to establish your lowest possible heart rate. This resting heart rate drops with increased fitness, which makes it an interesting number to watch over time.

    Even though I only recently established my true resting heart rate, noting my ‘sitting around’ heart rate turned out to be interesting too. I’ve known that for the last several years that my sitting HR, like when my blood pressure was being measured, had been 75-78 beats/minute. But the surprise came when I recently noticed my heart rate was in the low 60‘s when I was sitting. I was certain that the monitor was malfunctioning but it wasn’t--Bill simultaneously measured my HR manually and confirmed the number.

    Apparently the increased exercise intensity during our first 3 weeks in the mountains was being reflected in a dramatic increase in my CV fitness and a lowering of my heart rate.  (When you become more fit, your heart can pump larger volumes of blood and therefore it doesn’t pump or beat as many times per minute.)  Of course, I immediately wished I’d been tracking either my sitting or resting heart rate more closely so that I could have watched its decline but knowing that it had rather abruptly changed was a bonus.

   

Zones

    Zones are calculated from your all-important maximum heart rate. There are endless myths and opinions about training zones and I’ll leave you to choose your own to follow, but the following is the stripped-down version that we have been using for months:

    50-60% of MHR for warming up

    60-70% basic weight management

    70-80% CV or aerobic training

    80-90% hard training

    90-100% anaerobic


    The above list only uses your MHR to calculate your training zones but a more accurate calculation of your zones requires subtracting your resting rate from your maximum, calculating the percentages from this difference, then adding the resting rate to those numbers. For example, a maximum heart rate of 175 minus a resting rate of 60 equals 115. The 115 beats/minute is used to calculate the zones, so 70% times 115 is 80. Add the resting rate of 60 to the 80 for 140 as the bottom of the CV training zone. This 140 happens to be the 80% number using the more simple formula--another head scratcher for the newcomer!

    For months we used the more simple calculations, without the correction for resting heart rate, which is what the following experiences are based upon. 

   For me, with a current measured MHR of 175 beats/minute and using the more simple formula, I am targeting being over 70% of MHR or at least 122 during the “producing” time of my workouts. If I’m cruising along in the 140’s (the 80-90% bracket), all the better. And when I hit 90% or 157, I know I won’t be there long, but of course I can feel that myself.

    Bill’s situation is different. His current MHR is 169 and 70% of that is about 118 and it’s a significant effort for him to get to and hold 118. Worse yet, he is certain that his MHR is higher than the current 169 (probably at least 173), so that 70% zone is going to feel even farther out of reach.  He cringed at his own early observations from using the monitor: “I’ve been dogging it.”

    Some say that it is dangerous to go over 90% of MHR; others claim it is a good place to go briefly, now and then. And of course, how do you really know what your max is if you never go over 90%? After our dueling computers did a flurry of online research, we have sided with the “go there” crowd and are convinced that for us it is not dangerous to go over 90%. Do however make your own decision based on what you know about your health or seek guidance from a health care professional.

    The most disappointing conclusion from establishing preliminary MHRs and calculating our simple-formula exercise zones was that the brisk urban walking we do when at home doesn’t count as cardio-vascular exercise.  Walking is a great way to commute, it’s good for our bones and mental health, but unfortunately it is inadequate for either of us as a CV workout. My aerobic training zone is 122 or higher and I can’t crack 100 when walking on mostly flat ground. I need to either break into a jog or walk uphill or up stairs to pop my heart rate into a productive zone. 

    Using the monitor has been a wake-up call--it’s informed me that my overall off-season workout strategy when at home is not sufficiently intense. Fortunately I’ve been slowly reinstating running, but as a forefoot striker, which now looks like a critical source of year-round CV exercise for me. Using the heart rate monitor has moved my reconditioning-to-the-stresses-of-running project from the ‘nice to do’ category to the ‘must do’ level.

    We were feeling pretty pleased with ourselves and getting comfy with tracking our zones when I read online about jazzing up those zone numbers by subtracting your resting heart rate from the maximum beats per minute before doing the zone calculations. What was doable for me was now looking like a strain and Bill paled with distress from what the new numbers meant to him.

    But the take-home lesson for us remains unchanged: keep an upward pressure on our heart rates when we are biking and hiking and don’t sweat the details. The numbers are useless unless they motivate us, so for now we’ll stick with the simple formula because its numbers are motivating us to work harder than we have in the past. We’ll revisit the more aggressive training zone numbers in the future when we are more capable, when we need another motivation boost. There is no benefit in getting discouraged and abandoning use of the monitor.


In The Mountains

    Our appreciation of the other subtle guidance from the heart rate monitor (HRM) skyrocketed when we were pedaling our loaded bikes in the mountains, especially on steep grades in the August heat. There were several lessons learned  in quick succession.

    On the 2 days that we battled our way up a road where 10% grades started to look flat because it was otherwise so steep--a route for which we could have loaded our bikes and gear on an Austrian intercity bus with bike racks-- the HRM reassured us that pedaling was the right decision.  The combination of the persistent steep grades and the heat meant that we were inadvertently doing interval training: we were pushing ourselves to our limits for 1-3 minutes of effort and then resting for a couple of minutes out of desperate necessity.

    We repeated this “it’s the only way we’ll make it” strategy of high output and rest over and over again on a number of days to make it up the roughest stretches and once again realized that we would not have had the discipline to stress ourselves to that degree in a gym. At least on these mountain roads we had rewards for our effort: we had fresh air and stunning views to sooth us as our gasping settled down to breathing hard and there was the nice mountain hotel waiting for us each night. It was a good reminder that “Yes, we need to frequently work this hard, that this is what it takes to really be fit, so quit your complaining and do it.” (And besides, we need to be able to work at that level because such buses aren’t usually an option.)

    The HRM was also highly instructive about fluctuations in recovery time while we were doing this ad libbed interval training. Never mind the 1 or 2 minute recovery times used to assess fitness, we were monitoring recovery to better gauge when to start pedaling again. Usually the full-chest pounding sensation from being at or over 85% of max would subside for me after about 40 seconds of rest and at a little over a minute my heart rate and breathing would feel comfortable again. But especially when overheating crept in as an issue on the steepest grades, Bill would notice that his HR that is normally ready to plummet 50-60 beats to below 100 would hoover around 110. It was an instructive bit of feedback that suggested he should rest another minute or 2 before heading onto another stiff grade, waiting until his heart rate was down into the usual 90’s under these conditions. Starting too soon would result in him needing to stop sooner and perhaps needing to take a significantly longer rest to regain his performance ability. We knew from experience that it was more efficient to cool-down frequently and early than to get overly hot and the monitor refined his judgement about when he was pushing too hard.

 

Which Monitor?

    I didn’t do a lot of research before purchasing our Timex T5G971 from Amazon.com for $40 in December of 2010.  The first decision criteria became buying a monitor designed so that the customer can replace the batteries. Sending the device off to the factory every time 1 of the 2 batteries needed replacing doesn’t fit my lifestyle at all. Having high-end model that off-loaded data to our computer was enticing but really, what I wanted was a MHR, so I resisted the expensive temptations. From there I read online reviews, weighing reliability, ease of use, and low price most heavily in my decision.

    Unfortunately, our monitor has failed miserably in the reliability category, despite the glowing reviews to the contrary. A few times it’s turned itself off for no apparent reason. And the heart-breaker for me was on the above mentioned 45 minute hard push up a 2000’ trail it froze literally as I was peaking. I was in the last 30 seconds of my event and had broken into a jog on a steep rocky trail and it was reading in the 170’s and the next second I looked down it was stuck at 153. I’ve watched my heart rate drop after a big effort and know that it takes closer to a minute, not 1-3 seconds, for my heart rate to drop like that. I held the watch part close to the chest strap portion hoping it would quickly register credible readings but it remained stuck on 153. This was the most disappointing failure but not the first. It’s also registered a HR of 72 when I was walking and yet my standing-around heart rates are usually in the 80’s. I sent it in for servicing when we returned from Europe in mid-September and it was returned almost 2 months later while I was out of town. Hopefully it will perform flawlessly when I reconnect with it in December.

    The second aspect that is disappointing to us is the “Recovery Time” function. Recover time (RT) is how far your heart rate drops from a peak reading in 1 minute. Ideally you trot along until you register a high HR, you stop moving, hit the RT button on the watch, wait for the 1 minute interval to pass, and you get a reading that is yet another measure of your fitness.

    We’ve read that when manually counting your pulse to get a RT that you don’t start counting until your pulse rate begins to drop, which doesn’t happen as soon as you stop. There is a lag of some seconds. We assumed our monitor would be smart enough to wait for the drop in HR before beginning its 1 minute interval, but it doesn’t wait. As soon as we press the RT button it dutifully starts counting down, regardless of whether our HR has started down or is still going up. The result is that our monitor under estimates our RT and therefore underestimates our fitness. I don’t know if other models are cagier about measuring RT’s or not, but it is a feature worth shopping for the next time.


Go-No Go

    If you are on the fence about using a heart rate monitor, I’d highly recommend that you try one. Perhaps you can start by borrowing one from a friend who has lost interest in theirs. Like many exercise aids, they can either be a toy that loses its luster shortly after Christmas or can become a mainstay of your workouts. But even limited or intermittent use of a monitor is likely to boost the effectiveness of your workouts.

    We share one between us, which is good enough. And being forced to share it makes it more coveted. I’ve noticed on many days I find myself saying “I don’t want to bother” and yet every time I use it, I am fascinated by the information I receive. The monitor spurs me pedal a little faster when we hit the flat stretches on the roads and to push a little harder on our hikes. And even after 2 months of fairly intense use of the monitor, we’re still making startling discoveries.

    And remember, the key to your success is using the heart rate monitor as a motivational device. You are in charge:  you pick the formulas, the strategies that motivate you to do better and never mind what the pro’s are doing.