All Stressed Up And Nowhere To Go

Ever have one of those mornings when you didn't feel like getting out of bed for the morning run? You talk yourself out of bed and into the morning pre-run ritual. You might even muffle the little voice in your head long enough to step out the door. Maybe you get a mile up the road before SOMETHING finally clicks in your head and you receive the urgent message. You know the one:

What. Are. You. Thinking?

There are mornings, sometimes days, when our body tries to inform us it hasn't completely recovered from the stress of days past, which may or may not include our training. A heart rate monitor is an inexpensive tool to determine or predict whether we've endured a little too much stress.

I've used a heart rate monitor as part of my training for the past six or seven years. It's a simple tool to figure out your resting heart rate first thing in the morning. Some folks like to use the monitor to maintain their run pace. The heart rate monitor can also be used to help quantify a workout effort.

An athlete's resting heart rate can show the progression of fitness, as well as the onset of overreaching (not so good) or overtraining (not good at all). Some will place the heart rate strap when they go to bed, then turn on the heart rate receiver for a minute after waking up. Once the athlete learns their average heart rate, those mornings when sudden spikes of five-or-more beats-per-minute are read can tell the athlete about residual stress, or that the body has not completely recovered.

A resting heart rate can also be checked just as easily by placing a finger on the carotid artery and counting the pulses for a minute, but machines are more likely to be honest than human beings about the numbers.

I know folks who like to pace their runs based on a target heart rate zone. I prefer to go by feel than by heart rate for a number of reasons:

First, the heart is a demand pump. The oxygenated blood is sent to the places the body informs the brain it is most needed. That means there's a lag time between an effort is performed by the muscles and when the blood arrives to replenish the muscles...kind of the reverse of the way our automobile's carburetor works.

Second, depending on hydration (or dehydration), weather conditions, fitness, etc., a particular pace effort can vary in heart rate. A six-minute-per-mile pace is not always going to equate to a 145 beat-per-minute rate, just to give an example.

Ever ask someone how difficult a particular workout was? How do they usually describe it?

Dr. Eric Bannister researched training impact, scoring by percentage of maximum heart rate, multiplied by duration. Each ten percent above the fiftieth percentile earns a single point for each minute of effort. So a sixty-minute run at fifty percent of max heart rate would be a training impact score of sixty. That same sixty minutes at sixty percent max heart rate would score 120, a 180 training impact score would be seventy percent max for sixty minutes, and so on. Most good heart rate monitors have a function which informs the user how long their effort was in a particular range, or provides the average heart rate for the workout period.

Bannister and others also researched whether the Borg (perceived effort) scale of one-to-ten could be used to score training stress. They found most experienced athletes scored their perceived effort almost as accurately without a heart rate monitor; an athlete who scored their workout as a six-out-of-ten was found to have had exercised at around sixty percent of maximal heart rate. So you don't necessarily have to use a heart rate monitor, but you can get deeper into the details with one on your wrist/chest.

Once the workout is scored, the question soon follows as to what that score means to the individual.

Hunter Allen, one of the developers of the Training Peaks workout software, in a recent article, correlated training stress scores to levels of stress and need for recovery. He wrote that scores of:

- less than 150 = low stress. Recovery from this effort is generally complete by the following day.

- 150-to-300 = medium stress. Some residual fatigue. Generally complete recovery by the second day after the workout.

- 300-to-450 = high stress. Residual fatigue remains even after two days.

- more than 450 = very high stress. Residual fatigue over the next several days is likely.

While it's important to know how hard we run or work out, it's more important to realize gains in strength, speed, endurance and overall fitness come as we allow our body to properly recover from the effort. Once we completely recover we can go out and repeat the stress again, which makes our body more resistant to that same level of stress.

I've Got You Onto My Skin: Heart Rate Monitors

I've used chest-strap heart rate monitors for probably the better part of six years, & seen the good, the bad & the ugly of them. In spite of it all I consider them one of the tools which should be in every endurance athlete's arsenal, for a number of reasons:

First, heart rate monitors are great for checking the resting heart rate first thing in the morning.

Second, you can use a heart rate monitor to determine whether the recovery period during hard "interval" workout sessions is sufficient...or if it's time to pull the plug on the session before you begin overtraining.

Third, the heart rate monitor can help you ensure your "easy" training days remain just that...easy.Some high-end monitors are capable of calculating the amount of oxygen taken in to restore the body to it's original resting state, the effect of the training on the athlete; some will even recommend the effort level of the next exercise session after a brief analysis of the data. Naturally, many of these calculators are closer to the one size fits many rather than the individual side of the training device continuum.

Even the most simple monitors, which can download data to the athlete's personal computer, need to be calibrated to the individual in order to be most effective.

The most common - and most commonly incorrect - formula to determine maximum heart rate (MHR) is the classic 220-minus age. If a guy like me uses this particular formula, then my maximum heart rate (then used to determine training heart rate levels) should be 220-47, or 173 beats per minute. This would make my "easy" day heart rate (50-60% MHR) somewhere in the range of 86-to-103 beats per minute. High aerobic pace (61-to-80% MHR) would be 104-to-137 beats per minute.

Now, let's place a wrinkle in the equation. This formula was calculated using men. What guidance do I use as a coach when dealing with a female athlete? A recent Northwestern University study gave me a whole new formula to memorize: 206-minus-88%-of-age. So, one of my female athletes recently purchased a heart rate monitor; she can use the Gulati, et. al. calculation to estimate her MHR: 206 - (48 x .88) = 206 - (42.24) = 163.76...OR...164. Her "easy" day training rate would be in the 82-to-98 range; her high aerobic pace would be 99-to-132.

Of course, that also assumes the ability to drop the heart rate down to zero. I'm no Zen Master, so I can guarantee my high-to-low heart rate range is definitely not 173 beats. My daytime resting HR (RHR), sitting in my office without any hassle, is 54...about two beats higher than my (highest) resting rate first thing in the morning (when I'm fit & race ready it's as low as 42). So, for purposes of this post, let's just say my RHR is 50. That gives me a heart rate reserve (HRR) of 123 beats.

Karvonen would say the lowest target heart rate for my "easy" day (50%) should be: (173 -50) x .50 + 50 = (123 x .50) + 50 = 61.5 + 50 = 111.5. So, my highest target heart rate for the "easy" day (60%) is probably around 122. Keeping the heart rate reserve in mind "justifies" that slightly more intense workout on the "easy" day, right? Maybe.
But, in order to really get the most out of a heart rate monitor, the athlete needs to ensure they do a few things:

First, learn their "true" resting heart rate. This might take strapping on the monitor for a couple of mornings in succession. A good way to do this is - if you're like me & have to get up in the middle of the night to "exchange" fluids - put the strap & receiver on. When the alarm goes off, start the monitor. After about four or five mornings you'll have a good idea of the average.

Second, find out their "true" maximum heart rate. There are physicians who will perform a stress test (for a few dollars) if you have nobody available to assist you. Sally Edwards (and a few other coaches) recommends the test be taken on a track, but I'm partial to using a treadmill because the speed can be increased incrementally through the test, & elements which are hard to control on a track can be controlled with a treadmill.

- Start the test with an easy warm-up of at least 5 minutes. The goal during the warm-up is to get the heart beating to 100-120 bpm.
- Without stopping, begin the test by gradually accelerating the speed so the heart rate climbs about 5 bpm every 15 seconds.
- At each 15-second interval, your partner should tell the exercise time, heart rate, and offer encouragement as they gradually increase the speed.
- Within a 2-to-4-minute period, the heart rate should cease to climb even with increased effort and pace.
- When you can no longer accelerate, or you hear your partner repeating the same number you've (probably) reached your maximum HR.
- At that point either you or your partner can call an end to the test.

Third, & most importantly, learn to correlate effort with number. I've learned the hard way that technology fails, & often at the worst possible moment...on race day. Believe it or not, the experienced runner or athlete can figure out, within a few percentage points, just how hard they are working in terms of their maximal heart rate; researchers proved a strong correlation between the Borg (perceived effort) Scale & the percentage of maximum heart rate. So if you're an experienced runner, running at a level of nine on a one-to-ten scale...chances are good you are fairly close, give or take a few points, to ninety percent of maximum heart rate.

Remember - the heart rate monitor, much like the GPS receiver, is a tool. You can place one in the hands of a child & wreck things, or you can place it in the hands of a craftsman & watch beautiful things happen. The right tool, in the right hands, at the right time, for the right purpose.