Exercise at higher heart rates: dangerous?

Factual Questions
1

I’ve always noticed that the heart rate as reported by whatever cardio equipment I’m on tends to be above the “fat burning” and even “cardio conditioning” levels recommended on the little graphs on those same machines.

That never much bothered me, but as I’m getting older I’m thinking maybe it should. I’m in my early 40’s, and my heart rate about 20 minutes into the workout starts topping 170 - and tends to peak at about 179. If I lower the intensity to where it’s back to the 150’s, it doesn’t feel like much of a workout to me.
I do cardio about thrice weekly. I am overweight. Resting heart rate is about 65-70.

I know that the hear rate monitors on gym exercise equipment are notoriously unreliable, but I suspect they can’t all be off 20% in the same direction - so, should I be worried? (You are not my doctor, I’m not asking for medical advice. Googling heart rate and excercise tends to bring up discussions on the optimal heart rate to burn fat.)

2

How hard does it feel? A small percentage of people have much higher(or lower) maximum heart rates than the norm for their age group. I’m 48 and my max is 187.

The only way to find your true max heart rate is to either self test or get tested by a doctor or sports physiology lab.

Do not use the formulas that estimate a max rate, I suspect they will be useless for you.

3

How do you self test, or what do the labs/docs do to determine the max?

BTW I’m 51 and in above-average condition for my age and I am stunned to see that that the OP can exercise in the 170’s. My resting rate is about 53 and I can’t sustain a rate much higher than 136 for more than a couple of minutes before I get brought down by oxygen debt. I exercise between 155 (easy) to 135 (sustainable).

4

Assuming no medical conditions, this is how you calculate your maximum heart rate and your minimum heart rate.

220 beats per minute (BPM)

This is the theoretical maximum a human heart can beat and still pump blood. Once you go over that the heart is beating to erratically to pump blood correctly.

Next you take your age, say you’re 45

220 - 45 = 175

So for a 45 year old your theoretical maximum is 175 bpm. You should never excede this.

For optimal exercise you need to keep your heart rate between 60% and 85% of your theoretical maximum.

So

175 X .60 = 105
175 X .85 = 149

So you should keep your heart rate between 105 and 149

Now Olympic athletes are so fit that they work to 95% of their theoretical maximum

The fitter you get the lower your BPM will become as your heart strengthens. This is why as you exercise it becomes HARDER to get the 85%. If you start on a treadmill and your heart ZOOMS to 170 that’s a great indication you’re out of shape and need to cool it down.

Another great way of telling is if you can talk normally while running. If you are on a treadmill and cannot talk normally while running you’re going too fast.

The idea is this, what you want to do is run to where you can talk comfortably. Then you increase your pace till you feel if you talk it’ll be a strain.

HOLD that for 15 seconds. Then slow down to where you can talk normally. Then repeat it.
The next day do the same thing, but try to hold it for 30 seconds where you feel it’s a strain to talk. Then immediately slow down to where you can talk normally. Then repeat.

If you have no problems doing this continue. You should never move from 15 to 30 seconds if you feel faint or struggling for breath. You’re not fit enough at that point to continue.

Gradually you increase this program by 15 seconds. This builds your lungs and your heart.

When I first started running my bpm were 150. It’s very difficult for me to get that high anymore, because my heart has become that much more efficient. Right now even when I push myself my heart is 120 -130 where it used to be 150 -160. Even though I am pushing myself exactly, my heart over the YEARS became stronger.

5

Markxxx, that’s one of those formulas that are not accurate. They were developed for sedentary subjects. Max heart rate decreases very little if you stay in shape. My predicted MHR as above is only 172 but I can still reach 187.

Here are several different tests you can do depending on your current fitness and equipment.

6

I am 26 and overweight. My heart rate has been has high as 200 and is regularly over 185 while exercising. It may have something to do with the asthma medication that I take.

I have found that I feel extremely, extremely ill after exercising for as little as 5 mins at over 190. It is a shaky, nauseous feeling.

7

You are working way too hard.

Watch the finish of a local road race and you will see plenty of runners dry heaving and throwing up.

General fitness gains can be had at much lower heart rates. Pushing to high rates and anaerobic work is for racing fitness and has little to do with overall fitness.

8

I’ve wondered about this myself. I’ve managed to convince myself to go to the gym, and I use the “you should be able to talk easily” thing. What I’m doing is half an hour on the elliptical machine at about 60-70 rpm. I’ve been bumping the tension up over time, keeping it at about what my calf muscles can stand half an hour of. I don’t get terribly out of breath, or notice my heart hammering, but it pushes my heart rate WAY above the charts, according to the sensors in the machine’s handles. It’s going into the 170s, sometimes into the 180s from around 90 after the first minute or so - I’m 56. As noted by the OP, if I keep the rate down, it doesn’t seem like I’m doing anything. Because I have this suspicion I’m supposed to, I back off to about 45 rpm, and let my heart rate come down about 10-20 beats at the end to “cool down”, and it really seems slow.

9

Same thing for me, yabob. If I work out at a pace where my HR is under 160 or so, it doesn’t feel like I’m doing anything. That would feel more like a walking pace than an exercising pace.

10

Another “me too”. If my heart rate isn’t about 170, I’m not working hard at all. I’m a bit concerned about this too as I’m 55 now and apparently no longer bulletproof health-wise.
How can I find out if I’m one of those people who just has a high heart rate during exercise? runner pat, you mentioned there are tests that can determine whether a person has a high exertion heart rate - do you know how they determine what a person’s actual max heart rate is?

11

I posted a link in post #5 to some self tests.

The basic idea is to drive yourself in an all out effort to the point you just cannot keep up the pace, you should be at your or very near your max HR. It does depend on your willpower to drive yourself to the brink. In a lab, they put you on a treadmill and at regular intervals increase speed and/or incline until you signal you’re done. Either way, hellish.

12

The recommendations are part cautionary limit, part practical. Most people can’t sustain a level of work that puts their heart rate much higher than the supposed “fat burning” zone. The recommendations are, as others have said, based on a relatively sedentary untrained population. If you want to put in time rather than focus on speed or power, then you need to keep your heart rate to a level that allows you to continue exercising without becoming overly fatigued. That range is, for an untrained person, around the recommended min/max.

The dry heaves/puking that runner pat mentioned is due to the runners having pushed their limits a bit. They were running at or over their lactate threshold for too long. It’s occasionally useful to push to the point where you’re testing the limits of your ability to sustain the activity, but it’s extremely unpleasant.

From a performance point of view, training your lactate threshold response is particularly beneficial. While VO[sub]2[/sub] max is more or less set by genetics and does not respond particularly well to training, your LT is very trainable. HIIT, which has the athlete spike up around the lactate threshold for short periods has been shown to increase both anaerobic and endurance performance, increase fat loss, and boost post-workout metabolic rate superior to traditional aerobic long slow distance training.

If you’re just exercising for health reasons, anything that keeps you active and uninjured is preferable to being sedentary. On the other hand, heart attacks are more often triggered by sudden and dramatic increases in heart activity than steady-state stress, and there is some evidence that endurance events can induce heart damage. “EICF has been demonstrated in healthy subjects following a 20km run and a 60-minute cycle ride. It is therefore possible that EICF may affect mere mortals as well as the super-heroes taking part in ultra-endurance events.” (http://www.pponline.co.uk/encyc/cardiac-fatigue.html)

Occasional training by exercising at a level that spikes your heart rate up probably has some prophylactic effect against exercise induced tachycardia, and might be safer over the long term than running 20 miles on a regular basis. Or it could cause you to drop dead due to a previously undiagnosed problem. YMMV and IANAD.

13

I’m always amused by the 220-age, etc formula. At age 80, after exercising vigorously all my life, I could still get my heart up to 150 or more climbing a mountain fast. According to that, 140 would be my maximum heart rate, and 80 percent of that would be 112. I can get 112 just with easy exercise. My resting heart rate is in the low 50s. That is after 20 years of running and 15 years of climbing mountains and hiking daily, with four mountains higher than 14,000 feet climbed. A fit heart recovers very fast also, and after only a minute or two on a summit, my pulse drops from 150 or so down to 80 or less.

Keeping fit exercises the heart and that muscle becomes as strong as all your other ones.

14

I don’t think anybody is actually addressing the OPs question, which is:

a) Is it medically dangerous to sustain a heart rate near your max?
b) What will happen?

15

I did, including links, so did runner pat, including links.

A) Possibly. But then again maybe not. It really depends on you, your genetic background, what your current conditioning level is, and lots of other factors. If you’re over 40 you should probably check with a doctor or a sports-related medical professsional to get an individual answer to this.

B) i. Nothing
ii. Good luck trying to hit the max. Athletes with an average to intermediate level of conditioning probably can’t stress their cardiovascular systems enough to get very close to their max without exhausting or injuring themselves first because their musculoskeletal performance is a bottleneck.
iii. You could die.
iv. Spam.
v. Miscellaneous.

16

My question has been sorta answered - apparently, it depends.
To be more specific: it appears that my actual max heart rate is somewhere north of 200. (I tried to raise it a few days ago, and at 200 it gets quite uncomfortable)

at a heart rate of 172, my perceived level of exertion is not all that high - I can talk reasonably well.

I know I’m going to die. Will regularly excercising at 165-175 bpm instead of 150-ish speed the coming of that tragic event, or postpone it?

I’ve made an appt with my doc to ask this question (and do my semi-annual checkup), but don’t expect a specific answer from him. Will share what he says anyway.

17

Once you establish your max HR, you need only worry about the % you’re working at.

isosleepy, just to use your case lets say your max is 210. 75% of that is 157. Your 165-175 is 78-83% which is a good workout but not real hard.

In other words, don’t worry about it, you’re working in the proper range.