Running: Pace vs. Heart Rate

I’ve had the question while running in Charleston in the heat of the summer…should I be running based on Heart Rate (HR) or Pace?

My Heart Rate is significantly higher on hot days, or more properly, for the same Heart Rate, I’m running at a slower Pace than on a cooler day…the question is:

If I run at 140HR, on a hot day at 10 minutes per mile, is that the same workout as a 140HR on a cooler day at 9 minutes per mile?

I’m reminded that the pacing approach was something promoted _many_ years ago by running coach Jack Daniels.  His book, Daniels’ Running Formula was another one that I wore out, as I was originally ramping up my marathon training over 10 years ago.  He used benchmark running tests at various distances to establish a fitness level called vDOT, and used this to predict performance at various other distances.  I used it as a method to try to figure out how fast I could run a marathon. 

His premise was that pacing for workouts should be based on a benchmark all-out, running test like a 5K race…actually a few of them…to establish your vDOT…calculated by entering the time and distance information in a calculator (like this one)…and that all workouts should then be based on that vDOT pace, and that you could predict race performance at other distances from that vDOT, as long as you trained appropriately for them.

His view is that Heart Rate would be variable depending on lots of different factors, and that Pace should be the constant.  He uses the example of altitude, saying that if you were training at sea level at a certain Pace, that delivered a certain HR, and then did the same workout at altitude, that if you kept the same HR, that your Pace would be lower, and you wouldn’t be getting the same workout…therefore keep your Pace the same, and accept the higher HR, to get the same workout.  His view is that the work that your muscles are doing, is what improves them, and that Heart Rate is a secondary indicator of the work.

In addressing Heart Rate, Daniels says:

Possibly the greatest use of HR monitoring is to help avoid overtraining.  When standard workouts under ideal conditions produce HR values that are higher than typical, it is usually an indication that something is wrong…

I pulled that old book off the shelf because I had marked my progress in it.   I see that my original vDOT based on a 1 mile run was 35, and improved to 42 over time.  Will be interesting to see what it is now.

The Endurance Nation folks also prefer Pace over Heart Rate…like throw-out-your-heart-rate-monitor ‘prefer’…noting that in a recovery week an athlete might be running 9:00/mile in Zone 2, and because they’re tired in a higher volume week, that same Zone 2, may only be 9:35/mile.  Their view is that running a mile in 8 minutes, always takes the same amount of ‘work’, regardless of Heart Rate, and other ‘external’ factors:

Heart rate and perceived exertion are now external factors we use to add more depth to our pace training. Regardless of how you feel, your body should be able to run at the pace based on the results of your most recent test. If you are unable to meet the pacing targets in a particular workout, then you truly are fatigued and should consider cutting the workout short. 

Should (you) just throw (your) old Heart Rate Monitor away?  No. If necessary, you might be able to sell it to fund your new Pace training approach.

Of course, there are challenges to being solely Pace focused…first of all, knowing what Pace you are travelling at without running on a track or treadmill all the time.  I use a Polar 625x with a foot pod, that tells me what my Pace is, although in practise I find that it jumps around a bit…but close enough to give me an idea of what I’m doing.  And then hills…and where I live now, it’s all hills, all the time…the Pace proponents acknowledge the challenge, suggesting that you slow down going up, and speed up going down, to come out to the target average Pace…of course, this is a best guess at the time, and you’ll really only know when you look at the results at the end of the workout.

Heart Rate, aside from the weakness of ‘variable on other factors than just workload’, is easy to monitor, although there is a lag between increased effort and the increase in Heart Rate, particularly on shorter intervals…on the bike, I’ll move up to the Power level that should give me a particular Zone and then wait for the Heart Rate to get there…and then adjust in subsequent intervals, based on how my body is responding.

My Summary

I think that both Heart Rate and Pace are helpful workout tools.

My training has largely been Heart Rate focused on the bike and on the run. I also use Power on the bike, depending on the workout.  I’m left thinking, that the Pace thing makes a good point.  If I want to run faster, I’ll need to run faster…makes sense.  There have been a few treadmill interval workouts, where I’ve had a target of Zone 3, and my ‘normal’ Zone 3 pace is putting me into Zone 4, so I’ve slowed down to stay in Zone 3…I’m thinking I should stay with the Zone 3 ‘Pace’, and accept the higher Heart Rate.

…and in the heat, either specifically workout only when it’s cool (_very_ early), or move it inside to keep up the Pace component, or accept the higher Heart Rate, and maintain the target ‘Pace’.

Of course, the first step to building in more Pace awareness, is to set the vDOT, so that I’m clearer what my Pace should be for different workout types…will look for a few 5K races over the next few months, or push a few 5K’s on the local track to establish a vDOT, and be more aware of my ‘Pace’ rather than just Heart Rate.

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