Training with a Heart Rate Monitor - A Return to the Basics
HEART RATE MONITORS
When I began bike racing in the early 80s barely anyone raced or trained with a heart rate monitor (HRM). In fact, the first HRM was developed in 1975 by Gregory Lekhtman, which was followed a few years later by the first wireless unit developed by Polar Electro Company and used by the Finnish National Cross Country Ski team. It wasn't until the mid-80s that wireless HRMs were available to the public, but in all honesty, I was happy with my simple Avocet bike computer, perched on my handlebars and informing me of my speed and distance. Training with a HRM was still new and it wasn't until the late 90s before we started to see publications on training with an HRM (Precision Heart Rate Training by Edmund Burke).
Since then, heart rate monitors have come a long way with early versions looking more like wrist top computers (can you say beam me up Scotty?). Today’s HRMs are much smaller and really no different in appearance than your standard sports watch. Companies like Suunto, Polar, Garmin, Timex, Nike and Fitbit offer a wide range in HRMs with prices going from just under $50 to over $800 depending on the extra bells and whistles you want.
As for the ‘bells and whistles’, today heart rate monitors can offer far more than just heart rate and lap time. Companies are integrating the use of either GPS or a foot pod so people can see their current running speed, cadence and distance traveled [foot pod is a small device that attaches to your shoe which maps your run stride much the same way a Wii game station hand held controller can track your movements]. Add in a bike pod or GPS and your HRM eliminates the need for a bike computer, as it will display cycling speed and distance statistics. Some models (like Suunto’s Spartan or Ambit series) will allow you to see even more detailed statics such as estimated VO2, METS (measure of energy expenditure), altitude, and Training Effect (how hard the workout was). Afterwards, one can download the data to the web for further analysis or to share with your friends (great opportunity for a little smack talk among training partners). Also, those constricting heart rate straps are slowly being replaced by 'optical lens' on the back of the watch face, which measures changes in blood flow by shining a light from an LED through the skin and measuring how it scatters off blood vessels.
Which HRM to buy? That is a bit out of the scope of this article but best to start with a budget and decide which features are most important for you and then do some research. I would first say ask your friends and training partners what they use, after which here are literally dozens of reviews to read. Here are a couple "Best of" articles to get you started! 1. PC magazine's Best list -
2. Price Runners Best list - https://www.pricerunner.com/test/heart-rate-monitor
3. Masable's Best list - https://mashable.com/roundup/best-fitness-trackers-smart-watch-heart-rate/ 4. Men's Health Best list - https://www.menshealth.com/technology-gear/a26453022/best-gps-running-watches/
Why use an HRM? I am a huge proponent of wearing a heart rate monitor (HRM) while training for many reasons, however there are some limitations that must first be understood. First, your heart rate is influenced my many factors, especially temperature and fatigue. Ever compete in a triathlon or 10k race in the middle of August? Your heart rate will elevate more under hot and humid conditions than with cooler weather. Fatigue is another factor. Lets say you've been sidelined a few days with an illness. Under that scenario, you will find it very difficult to elevate your heart rate into the proper training zones. Altitude will also have an affect on heart rate, as training or racing at higher altitudes will lead to an elevation in heart rate. Another limiting factor for training with heart rate only is the lag. Say you want to do a series of 30 second near maximal intervals. It would be tough to utilize your heart rate only as a gauge of intensity as it will take time for your body (and heart rate) to respond to the increased effort. So, in the case of a short 30-second interval, it may be over even before you see your heart rate elevate into the appropriate maximal zone.
The final limitation to using heart rate as a guide is the concept of heart rate drift (HRD). HRD refers to the tendency of ones heart rate to slowly ‘drift’ higher over time, even though you may be keeping a steady effort or pace. The longer duration of the effort, the more the heart rate will drift higher. Several years back I ran a fall half marathon with a friend of mine. Our goal was to take advantage of the cool fall weather (low 40s at the start of the race) and try to set Personal Records (or PRs) on a relatively flat course. Our goal pace was right around 6:20/mile and like a fine Swiss clock, we clicked off mile after mile within 2 seconds of that pace. For the first handful of miles, my own heart rate hovered around 158-160bps, but as the miles pilled up, even though I was still running that same 6:20/mile pace, my heart rate began the slow creep up to where it eventually reached the upper 160s with 2 miles to go. To properly use HR as a training guide, you must have a working knowledge of your own HR zones and to determine these zones accurately requires performance testing.
With high end training centers popping up across the country, performance testing is no longer just for the elite or professional athlete. Specialty centers such as Cadence Cycling and Multisport in Philadelphia, Hospital for Special Surgery and Chelsea Piers in NYC, Fast Splits in Newton Mass, Cycle Life in Washington DC, (just to name a few), now offer professional level performance tests such as lactate threshold or VO2 max tests to the amateur athlete. Want to out ‘science’ that younger crowd who may not be able to afford such testing, here is your chance. Cycling and running performance tests not only allow you to get a better understanding of your current fitness level, they can provide a detailed road map on how to build your training to better achieve your goals. Are you someone who excels at pushing the monster gears on the bike with your buddies, but after an hour or so start to run out of gas? Or is it you have the lungs and power to succeed on the bike, but cannot seem to get comfortable while riding to take advantage of this. Here is your chance to answer all of these questions and more – for a price of course!
LACTATE THRESHOLD TEST
Your lactate threshold (LT) is the point at which your body can no longer effectively metabolize the accumulation of lactate in the blood. For an athlete, one is able to perform up to a certain level of intensity (referred to lactate threshold) without a noticeable change in performance. However, should your effort level exceed this ‘threshold’, your body will be unable to effectively clear the lactate from the blood quick enough, and your muscles will fatigue rapidly. Think of it as a red-line on a car’s speedometer – your fine at or below that magical red-line, but go over it and your risk dropping your transmission on the interstate!
Lactate threshold is one of the best predictors of endurance performance and for endurance athletes is expressed as power output at LT (as in wattage for a cyclist), or speed at LT (as in minute/mile for a runner) or percentage of Vo2 max. For a trained athlete, it is this LT level that can be dramatically changed through proper training over the course of a season.
Most centers will use a standard Conconi-type test for determining LT. A runner or rider will warm up (on treadmill or bike trainer equipped with a power meter), and after an initial interval of 4 minutes the resistance will gradually increase every 3 minutes. For the cyclist, the increase is usually 20-25 watts and for the runners about 0.3mph in speed. Between each interval a tiny prick of blood is drawn from the athlete’s finger and it is then measured for lactate on the LactatePro analyzer. When ones blood lactate reaches 4mml/L (or the tester sees a noticeable spike in the lactate levels), the speed or power level is noted, and the lactate threshold is determined. The corresponding data now becomes look at the athlete’s current level of fitness and will determine their heart rate and corresponding power (cycling) or speed (running) zones, as well as the athlete’s most productive training and racing zones.
While the output from an LT test can provide an athlete with a great framework from which to build their training from, the test does have limitations. First, there is the fact that one has to have their blood drawn for the test. Although only a finger prick is required, it still may be enough to keep the squeamish away. Second, because the blood is drawn every 3 to 4 minutes, there is a small amount of data interpolation required by the tester to determine the exact point of the onset of blood lactate accumulation occurs (referred to as OBLA). So finding the threshold in terms of watts for the cyclist or speed for the runner is not exact. Lastly, there is the cost. While not as expensive as a VO2 test (which can run $250 or more), a Lactate Threshold test typically costs $125 to $175.
Additionally, one may be able to closely replicate the output with a Field Test armed with a heart monitor and power meter (for cycling). Best way to perform a Running Field Test is to take your average HR and pace from a running race that takes you about 30mins to complete - so whether that is a 5km or a 5mi race - that average HR and pace will be very close to your THRESHOLD HR - or that same HR you want to hold (and not exceed) while doing the run portion of the NYC triathlon. For the bike, one would perform a 20min test (either indoors on a trainer or on a flat controlled course) and record average watts and HR for the duration of that ride.
Once you have your Threshold pace and HR, you can create a chart like the one below to building your training zones from. This runner has a threshold HR of 160bps and a Threshold pace of 7:08 / mile. Armed with that info, their long Endurance runs should be in Zone 3 (so HR range of 134-152bps and pace of 7:30 to 8:30 per mile). Should they want to do some faster intervals as a part of training - then they can look to Zone 4 (essentially race pace) and target 153-168bps for HR and 6:49 to 7:30 per mile pace. With training your threshold should improve, which means a faster per mile pace and a HIGHER threshold heart rate! So are you ready to take your training to the next level?