Heart Rate Monitoring for Swimming

by CoachBillG

Monitoring your heart rate is a great way for increasing your efficiency, your performance output or if you are overtraining and need to take a day or two off. The heart rate monitor is a very useful tool to monitor just about every endurance activity. However when it comes to swimming, you will have to make some modifications when you are doing your heart rate zone calculations.

Let’s say you calculate a number of heart rate zones for yourself using a formula (220-age, Karvorien, Maffetone’s MAF, Joe Friel, Hadd, etc.) and you have your “aerobic” and “anaerobic” zones. Whether you have 2 zones, 4 zones or 7 zones is irrelevant. Your goal is to perform at the highest level possible for your ability, be able to hold that indefinitely and in addition, have the ability to swim the later part of the swim faster than the first part (negative split). You want maximum output in the most comfortable zone possible. For longer endurance activities, that zone would be the upper level of your aerobic threshold. For most formulas and most people, that is at the high end of zone 2 to the low end of zone 3 or approximately 70 – 85% of your maximum heart rate.

I’ll use myself as an example. I like to use the MAF formula (180-age+5). I am 45 so my maximum aerobic heart rate is 140. My aerobic zone is 130-140. Once I go above 140 I am shifting from using primarily fat as a fuel source to glycogen. The byproduct of that is lactic acid. My goal is to get faster while remaining in this zone. If I were to use any other heart rate formula and calculate about 70 to 80 % of my maximum heart rate, it still falls in the 130-140ish range.

However, when you calculate these formulas, they are geared for running, not swimming. In running your body position is vertical and your blood pressure and the assistance of gravity are different than when you are horizontal, where your blood pressure is lower and there is no gravity assisting the blood to be pumped out of the heart and down to the lower extremities. Cycling falls in the middle where you have a horizontal upper body and a vertical lower body.

So, running at a heart rate of 140 feels very easy for me. In fact, 140 is so low, that most people would find it difficult to run at this heart rate because their heart rates would shoot up too high, well over 140. In swimming, if my heart rate went to 140, it would feel like I was suffocating and although I am still technically “aerobic”, I would feel like I am anaerobic. 140 in the pool to me feels like 160 at the end of a 10k road race.

I don’t want you to think something is wrong with you if you do a swim session and a run session at the same heart rate and they feel totally opposite in intensity.

If you plan on using a heart rate monitor take an additional 10 to 15 heart beats off your calculations for each zone and that will compensate for the horizontal position.

January 21st, 2012 CoachBillG. 4

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leftyna03

I currently use the Polar RCX5 while in the pool and it works great. The monitor will calculate zones based on your HR variability through its fitness test. My Max HR is low considering I am only 32 years old, 165 bpm running and 161 on the bike. I know this because I wear the monitor during races and when I give it my max effort at the end of a race I later evaluate the information on polarpersonaltrainer.com

My technique in the water is not great, therefore I consistently see zone 3 and zone 4 numbers (out of 5 zones).
lynnswim

Thank you Bill for your blog which I found both interesting and a bit worrisome which I will explain below. Recently I have incorporated the PACE approach to my swimming workouts as I have been getting a lot of aerobic exercise everyday from exercising our dogs but not getting much anaerobic. You are probably familiar with PACE but if not it advocates an exercise approach comprised of a series of short periods of exertion to get your heart rate to as close to maximum as possible. Total exertion time should be around 12 minutes but no greater than 20 minutes (after 20 minutes your muscles are deplete of carbs). This approach has really helped me lose fat and tone up and I feel much more energetic. At any rate, I calculate my maximum heart rate at around 167 which I generally achieve during my sets. I do a series of short sprints, 50m or 100m, for a total distance of 800 to 1200m, depending on how I feel that day (after 500 to 600m of warm up). I try to get in a total exertion time of at least 12 minutes and sometimes toward 20 minutes as recommended by the PACE approach. However, after reading your blog about how we should expect lower maximum heart rates for swimming, I started to worry, am I killing myself? Should I ease up on my workouts? I am 58 and think in good shape, have always been a fitness buff and used to swim competitively (including masters). My swim workouts are challenging and it takes me a day to recover. At any rate I would appreciate any thoughts you might have.
Also, in terms of heart monitors for swimming, I tried a wrist only monitor but it didn’t work well. So I tried a monitor which used a chest strap and this is more accurate but a bit inconvenient. The strap comes off easily while swimming. Wearing a t-shirt solves this but I don’t like wearing a shirt while swimming. So what I usually do is leave the chest strap on the deck and when I finish a sprint I grab the strap and put it to my chest to measure by MHR. But I know I lose some accuracy doing it this way. Lawrence recommended the Polar RCX5 but Lawrence does this require the use of a chest strap too?
http://www.fastertoday.com CoachBillG

Hi Lynn,

I am not familiar with the PACE approach. I did google it but nothing came up. Thank you for giving me the explanation

I am very familiar with high intensity training as I am an RKC Kettlebell Instructor and CrossFit Level I Coach.

I do agree that high intensity has it’s place and purpose for all athletes and sports. Some sport require it much more than others. An example is a amateur wrestling match which lasts 6 to 9 minutes requires much more power and intensity than a 40 minute 10k running race. High intensity training also helps in increasing testosterone production for men, which is very important after the age of 35. For people who are looking for overall health and fitness, you are on the right track, meaning mixing up both aerobic and anaerobic zones, reaping the benefits of both. No need to worry, no one is dying

As for the swimming, yes, it is much harder to get your heart rate to be the same as it is when you are running. Your maximum heart rate calculation of 167 is probably for vertical positioning (running, plyometrics, functional exercise movements, etc.) and not swimming. Even Joe Friel “Triathlete’s Training Bible” has different ways of calculating heart rate zones for different sports.

My approach to coaching all skilled sports (and all sports require skill) is to become extremely efficient at it in a very comfortably determined zone and increase your power wattage, pace, speed, etc. in that zone BEFORE training at higher intensity levels. The reasoning behind this is by staying comfortably “aerobic”, not having lactate acid build up in you muscles and feeling like you are barfing up a lung, you can put in more energy and effort focusing on your bio-mechanics and efficiency to get you faster. You become much more precise and less sloppy when you do this. I tell all the athletes I coach to look at their sport the way a great musician approaches playing their instrument, breaking it down, going back to the basics, improve on the timing, put it together and then break it apart again. You have to literally become a “student”.

As for taking a day to recover from one of your high intensity swims, think that you lost a day where you could have improved on something. If I were to make a suggestion, do a number of time trials with different distances and different set intensities and see how much faster you are really going by swimming that hard. You might be creating enough drag in the water to slow you down enough that it might not be much faster than toning down the intensity.

As for the heart rate monitors, I will post some information

Thank you for the comment and I hope this helps.

Best,
Bill
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