Clear as mud: Heart rate training

I don’t know a lot about keeping my heart rate in a certain zone. I just figured out what my ideal zone is. I’ve seen some posts lately that suggest longer runs at a “slower” pace keeps your heart rate in that aerobic (fat burning) threshold and you benefit more from it. I’ve also seen posts that say the exact opposite.  There’s a lot of information out there, I’ve been trying to weed through it.

  • Anaerobic Threshold: The point at which your body switches from using oxygen as its primary source of energy to using stored sugar. When you’re in poor physical shape, you hit your anaerobic threshold while exercising at relatively low levels of exercise. (source)

hr training

I always thought to get my maximum heart rate I subtracted my age from 220. Did you know women are supposed to subtract their age from 226? So, if I do that my maximum heart rate is….(drumroll)…190. I’ve hit 189 for sure. Maybe 190.

Then to find my zone I take 190 and multiply it by .50 and get 95, that’s my low end.

Then to find my high end, I take 190 and multiply it by .85 and I get 161.

My range for working out should be between 95 and 161 for an ideal workout. I have been ranging 160-170 which leads me to another discussion. Some research suggests that well trained runners can’t use the above formula to determine their max heart rate. (source)

According to, you should cross train at 70-80% of your max heart rate (source), which puts me at 133-152. And that’s about accurate for my cross training these days.

This is the best and easiest description I found. (source)

Zone 1

– 50-60% of max heart rate. This zone corresponds to an athlete’s aerobic base and is typically reserved for a warmup and cooldown.

Zone 2

– 60-70% of max heart rate. This is an aerobic zone where an athlete can run comfortably and utilize fat as a primary fuel source.

Zone 3

– 70-80% of max heart rate. This is the last aerobic zone before crossing the anaerobic threshold. Training in this zone is challenging but sustainable for most athletes.

Zone 4

– 80-90% of max heart rate. This is an anaerobic zone which by definition implies the absence of O2 resulting in a negligible amount of fat metabolism. Therefore, our bodies are primarily using carbohydrates as a fuel source. Athletes in Zone 4 may mutter only a few words at a time.

Zone 5

– 90-100% of max heart rate. This is the top of the heart rate chain and leaves you gasping for air after only 10 to 20 seconds of work.

I tend to run in Zone 4 (152-171). That zone does not burn as much fat. It switches to using carbs for fuel. If I train in zone 3 (133-152) I burn more fat, which is good since I have it to burn. But in my pea brain, that correlates to slower running. But, really I think it’s faster pace at less intensity. The more trained your are the less your heart has to work to do the same job.

So, I’m pretty sure that’s clear as mud, right??? I think I’ll just keep doing what I’m doing. At any rate, you should know what your heart rate range is for working out.

Do you work out with a heart rate monitor? What zone are you normally in?

Do you pay attention to your heart rate?

What do you do with the information?

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Let us run with endurance the race God has set before us. Hebrews 12:1

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