Betablocker and VO2 decrease (blood, depressed, couch potato, doctor)
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I’am 81, an avid fitness pro , training regularly for years( running, elliptical, etc). I am generally in very good health, except that I have now been on selective betablocker for theee years, following one occasional atrial fibrillation episode years ago. Typically, I run three times a week about 5 km .
I considered myself fit for my age, until my new Garmin fitness watch gave me an unexpected very low VO2 reading of 25, rated as poor.
I know that betablockers depress the HR , but I didn't think they would do so to the point of turning a self-perceived good fitness level ( for my age ) into a poor one. I have not set my age in the watch, but a 25 VO2 rating would be absolutely poor even for a 20 years old young person. I wonder then what a potato couch VO2 level would be !
I am all the more surprised, because several clinical studies indicate that our system compensates for the betablocker’s lower HR with a stronger systolic stroke, ie more blood ( hence oxygen) is pumped into the system for eac h heart beat.
In fact, as clinical studies seem to indicate, the betablocker’s effect on the HR is negligible for the average person working out .. In the end , it may well become relevant only for top athletes performing at high intensity levels.
I wonder if anyone has comments on this
VO2 assessment from a watch is not accurate. It’s simply a guess based on your heart rate.
If your average heart rate while running and pace per mile hasn’t changed much over the past few years I see no reason for concern.
What is a selective beta blocker-you just take when A-fib kicks in?
He means beta-1 (cardio selective) selective blockers which are used to treat high BP and various form of heart disease. Basically, pretty much any beta blocker prescribed nowadays would be a cardio-selective beta blocker to keep down unwanted symptoms as the non selective beta blockers acted on many tissues in the body.
In general beta blockers slow the heart, which reduces V02 max. Cardio selective ones reduce your VO2 max by 1 MET vs non-selective by 1.5 METs. That’s an average across all studies using healthy participants. A decrease in 2 METs is considered substantial so 1 should be noticeable. You can divide V02 by 3.5 to get METs.
VO2 assessment from a watch is not accurate. It’s simply a guess based on your heart rate.
If your average heart rate while running and pace per mile hasn’t changed much over the past few years I see no reason for concern.
What is a selective beta blocker-you just take when A-fib kicks in?
Thanks for the input.
I am on Metoprolol 50 mg 2x day.
No, my HR has not changed much over the past 3 years on Metoprolol, except that it has been depressed by about 15-20 bpm.
Going by the age charts,( 220 minus age ) my 85% HR should be 119 bpm, but I can't go by this, because it is like sitting on a chair.
In fact, my HR can easily go up to 160+ ( in spite of the betablocker, strangely) without too much strain for short bursts.
Usually my cruising pace is about 135 bpm, still way above the nominal rate by age.
My SPO2 reading after today's session was 97%. I don't know if and how this correlates with the VO2 max reading, but it was still 25( poor). Perhaps the low VO2 max reading is due to the fact that it requires high intensity bursts, but I tend to be a resistance runner and I hardly ever push my heart into overdrive.Even so, though, I shouldn't get a couch potato VO2 reading.
He means beta-1 (cardio selective) selective blockers which are used to treat high BP and various form of heart disease. Basically, pretty much any beta blocker prescribed nowadays would be a cardio-selective beta blocker to keep down unwanted symptoms as the non selective beta blockers acted on many tissues in the body.
In general beta blockers slow the heart, which reduces V02 max. Cardio selective ones reduce your VO2 max by 1 MET vs non-selective by 1.5 METs. That’s an average across all studies using healthy participants. A decrease in 2 METs is considered substantial so 1 should be noticeable. You can divide V02 by 3.5 to get METs.
I get it, but, bottom line, does this mean that the betablocker has practically no effect on cardio training?.
I wouldn't want to keep running ( and sweating!) just to wear off shoes!
I get it, but, bottom line, does this mean that the betablocker has practically no effect on cardio training?.
I wouldn't want to keep running ( and sweating!) just to wear off shoes!
It’s going to reduce your performance but you will still burn calories and give your heart much needed love and attention. Continue the workouts, just understand what you’re seeing is normal. The time to talk to your doctor is when you feel out of breath or tired doing normal activities. At your age your workout are quite impressive!
He means beta-1 (cardio selective) selective blockers which are used to treat high BP and various form of heart disease. Basically, pretty much any beta blocker prescribed nowadays would be a cardio-selective beta blocker to keep down unwanted symptoms as the non selective beta blockers acted on many tissues in the body.
In general beta blockers slow the heart, which reduces V02 max. Cardio selective ones reduce your VO2 max by 1 MET vs non-selective by 1.5 METs. That’s an average across all studies using healthy participants. A decrease in 2 METs is considered substantial so 1 should be noticeable. You can divide V02 by 3.5 to get METs.
People still take the non-selective ones for a variety of reasons. I take one and it is quite noticeable when I am doing stuff like doing stair climbing, biking on hills or for long distances, or hiking up hills or in higher altitudes. I just asked my neurologist if I could stop it for specific activities and she said it was fine for me as I take a very low dose.
Thanks for the input.
I am on Metoprolol 50 mg 2x day.
No, my HR has not changed much over the past 3 years on Metoprolol, except that it has been depressed by about 15-20 bpm.
Going by the age charts,( 220 minus age ) my 85% HR should be 119 bpm, but I can't go by this, because it is like sitting on a chair.
In fact, my HR can easily go up to 160+ ( in spite of the betablocker, strangely) without too much strain for short bursts.
Usually my cruising pace is about 135 bpm, still way above the nominal rate by age.
My SPO2 reading after today's session was 97%. I don't know if and how this correlates with the VO2 max reading, but it was still 25( poor). Perhaps the low VO2 max reading is due to the fact that it requires high intensity bursts, but I tend to be a resistance runner and I hardly ever push my heart into overdrive.Even so, though, I shouldn't get a couch potato VO2 reading.
"Maximum heart rate = 220 - your age" has been thoroughly debunked as frequently wildly inaccurate but still persists.
"Maximum heart rate = 220 - your age" has been thoroughly debunked as frequently wildly inaccurate but still persists.
Yes, so I heard, but then what is a more reliable method? I had read that there is one based on the resting HR and the " reserve" factor, but the betablockere artificially lowers the resting rate .. So, perhaps there isn't really a more reliable formula, because the betablocker is a variable that is difficult to fit into a standardized formula?!
Yes, so I heard, but then what is a more reliable method? I had read that there is one based on the resting HR and the " reserve" factor, but the betablockere artificially lowers the resting rate .. So, perhaps there isn't really a more reliable formula, because the betablocker is a variable that is difficult to fit into a standardized formula?!
Thanks
Ittiandro
I found what was probably much closer to my maximum a several years ago. I was cycling up a long and very steep hill determined to make it to the top without stopping. I heard a siren somewhere. I looked all around but I did not see anything like an ambulance, fire truck or police car, yet I could hear it -- not getting closer or farther.
Turns out it was my heart monitor watch freaking out! It was a good monitor with a belt on my chest communicating with the watch wirelessly.
The rate was about 35 bpm above the amount calculated with the totally worthless formula.
If you are super fit you can have a very low resting heart rate but that doesn't mean your maximum will be any lower. Without the influence of meds the maximum is pretty much genetics.
Most any really good trainer who thinks for him/herself knows the formula is worthless. If you read where it came from it was a couple of cardiologists on a train on their way to a conference. They were fooling around with numbers on a napkin and came up with 220- minus your age just speculating. Somehow it got out and took on a life of its own. They tried to disavow it to no avail.
At least, that's the story I heard.
Variations of the formula are worthless because everybody has different genetics.
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