By Coach Steve

Heart rate monitors (HRMs) revolutionized the endurance sport coaching business. HRMS are responsible for a new accuracy in coach—athlete communications that’s not possible by simply describing workouts in terms of RPE (relative perceived exertion), or 'feel.' But you might respond:"I’ve always trained by feel and it’s worked well for me all these years." I also trained quite well without a heart rate monitor for the first 15 years of my athletic career, but now that I use one for most workouts and occasionally during races, I have more control over my results. By tracking heart rates I’ve seen during specific workouts, I have reference points for over-training, under-training, the quality of my hard efforts, and recovery. I’d like to think that my ability to sense I’m doing just the right thing in training is infallible, but in reality it’s not. For example, sometimes when I have that euphoric feeling after a great race I feel indestructible. I know I’m supposed to do some easy recovery workouts, but what I really want is to keep that feeling going—so I hammer! Not smart. Fortunately, I’m wearing my HRM and I know I’m not supposed to go above a heart rate of XXX on recovery days. I back off so I don’t 'leave' my next fantastic race in training. At other times, I may be doing a hard tempo or time trial effort, but I just can’t get going. I look down at my HRM and it’s 10 beats too low for my relative perceived effort (RPE) level. In this case it usually means I’m over-trained and need a break.

Determine Your Maximum Heart Rate
This is the crucial first step so you can calculate percentages of your maximum heart rate as a guide. Not all athletes see their maximum HR in training or racing (it hurts too much), so initially there may some guesswork involved in your calculations. Here’s the rule for determining your maximum HR if you fit the average profile: For men subtract your age from 220 beats per minute, for women subtract your age from 227 beats per minute. This works well for about 40-50% of the athletic population, but the values for the rest can vary by as much as 10 beats on the low side or 20+ beats on the high side. Most athletes only get within 5 beats of their maximum while sprinting at the end of a short race. Some may get closer to their max when doing longish interval repeats on the track. The highest heart rates I’ve seen occurred while doing half-mile repeats in 100+ degree heat. Yes, that was nuts; do as I say, not as I do. Anyway, it may take a few track workouts or races with the HRM before you can determine your max HR. If the formulas above based on the mean for age and gender don’t work for you, I recommend adding 2 to 5 beats to the highest HR you’ve seen during run training or racing, for an estimated maximum. Aging reduces max heart rate; by the simplest rule your max should drop by 1 beat every year. This is not always accurate for endurance athletes over thirty who've been in continuous training. For some the drop may only be 1/2 a beat per year.

Determining Heart Rate Ranges (percentages of max HR)
This is fairly easy once you've determined your maximum heart rate. There are two methods: 1) A range based on zero (dead) to your max HR. 2) A range based resting HR to max HR. The latter was named the "Karvonen" method after a Scandinavian physiologist; it creates narrower ranges and is preferred by endurance coaches. The former method is often used at fitness facilities. Here’s how to calculate your percentage of maximum heart rate following the Karvonen method: We’ve already found what we believe to be our maximum HR, now we need to find our resting heart rate. The number I use is the lowest HR I’ve ever counted (or seen on the HRM) while sitting very quietly totally relaxed. I consistently find my lowest HR early in the morning, lying still in bed upon awakening.

To calculate ranges use this formula: max HR - min HR x percent as a decimal + min HR. For example to find 75% of max with 190 max and 50 min: 190 - 50 = 140 x .75 = 105 + 50 = 155.

Make sure you know which HR percentage method a coach is referring to when discussing training plans.

Now that you have a formula to find these percentages, how do they fit into a training plan?

Heart Rate Percentages and Training Effect
Each heart rate range has a distinct effect for your training. I’ll describe what pulse range is appropriate for each type of workout for runs.

Note: The ranges will be 5 to 10% lower for equivalent RPE for cycling.

65% to 70% This is an effort level considered appropriate for very easy run training and recovery days after tough training or race efforts.

70% to 75% This is the range for maximum aerobic training benefit, and moderate 'base' training that is not especially stressful to the body. This range is also the best to develop your metabolism’s fat burning capability for distance races like half to full Ironman. The majority of your training should be done in this range.

75% to 80% This is mild tempo training that helps to build your muscular/skeletal foundation for the rigors of racing. This range is especially valuable during the early pre-season phase when you need to 'toughen-up' in preparation for higher intensity training and racing.

85% This is considered fast tempo training. It’s not quite race pace (except for very long races) but it simulates race efforts without the need for as much recovery afterwards. This intensity should be performed as late pre-season training, and as a substitute for races when there are none available.

85% to 95% This is the race effort range. During a PR 5k race effort, you may find yourself holding 95% for the second half of the race. For a fast 10k you’ll probably be in the 90% to 95% range for your best effort. Also, when you do speedwork on the track you should expect to see a heart rate at or above 90% of max for much of the workout.

Some Finer Points of Training with a HRM
Your heart’s response to exercise is directly proportional to the amount of muscle mass being used for the activity. In other words, a sport that involves more muscle to propel your body, will demand higher heart rates. This is why observed maximum heart rates while running are typically 8 to 10 beats higher than cycling at the same RPE.

Most HRMs have a lag time of a several seconds between receiving the signal and the number you see, which is averaged within the unit. There’s also a lag time (heart rate drift) for your heart’s response to stress during warm-up and race starts. If you sprint-out in a race hoping to see your target HR during the first quarter mile, you could be in serious trouble later. This applies to any training or racing outing, since your pulse will gradually creep up (drift) as you warm-up, and also as fatigue sets in. When describing a certain effort level by percentage of max HR, the number is meant to be an average over the duration of the workout. A HR 5 to 10 beats higher is acceptable on tough hills as long as it drops back down afterwards. Also, when attempting an even or negative split for a training outing or race, expect to see higher numbers for the second half of the workout (again due to HR drift). If I want to maintain an average of 150 bpm over my entire workout - with even pacing, I’ll stay in the high 140s for the first half and low 150s for the second half.

Interference from other HRM units is a possibility when other athletes using HRMs are nearby. When you’re training or racing with others and you see a heart rate value that just can’t be right, consider whaether you're getting someone else's reading. It can happen in situations where you're very close to another athlete, or when the battery in their transmitter is stronger (perhaps fresher) than yours. You can also get a false reading in magnetic fields such as running under power lines.

I recommend using your heart rate monitor along with your own finely-tuned sense of perceived effort to assess your workouts and races. When you learn to combine the information from both sources effectively, the knowledge gained will allow you to maximize your athletic time and energy.