High Blood pressure medication and Exercise

I was just put on a beta blocker on Thursday. This is my first time on any kind of blood pressure medicine. I went to the gym today and noticed that I felt like I was working hard like before when my heart rate was 145-150 but today I couldn't get it to 120! The highest it got was 118. Which is barely in the fat burning zone. What the heck?! So, does this mean that since I am on these meds now that I am not going to be able to get my heart rate back where it was? I know they are supposed to slow your heart rate but really?!
I will be asking my doc about it, but they aren't open today. This medicine makes me feel very tired all the time and he did say if it had that side effect we would try a different one. But I have to stay on this one for two weeks for insurance reasons. What has your experience been? How have you adjusted your target heart rate?

The answer is "yes and no". Yes, you are likely burning slightly fewer calories (5%-8%), but not as few as the HRM indicates.

Once you go on a beta blocker, your HRM calorie counter is absolutely useless. I mention all the time the HRMs DO NOT measure calorie burn. They ESTIMATE it based on your heart rate. BUT....those estimates (and the algorithms used to derive them) are only applicable when you have a normal, average, steady-state heart rate response to aerobic exercise. Under any other condition, the HRM calorie count accuracy can be a little off or way, way, way off. In the case of beta blockers, it's the latter.

As you know, beta blockers blunt your heart rate response to exercise. However, that does not mean that you are not working at the same intensity. It just means the "scale" has changed. Your maximum heart rate is not much lower, and therefore exercise heart rates are lower.

Example: Pre-beta blocker, your resting heart rate is 70 and max heart rate is 180. A 70% effort (using the HR reserve method of calculation) is 147 bpm (( [180-70] x .70) + 70).

The beta blocker reduces you max heart rate to 130 and resting heart rate to 60. Now, your 70% effort is 109 bpm.

You are still working at 70%, and you are still burning roughly the same calories that you did before when you were working at 70% effort--it's just that the "speedometer" shows a different number.

Now, here is the "yes" part to burning fewer calories: Beta blockers do modestly lower your VO2max, usually by less than 10%. But that means you probably won't be able to work at quite the same absolute intensity (e.g. running speed) as before, and, thus you will be burning fewer calories.

You have also noticed that the side effects can include chronic fatigue.

For the reasons described above and others, beta blockers do make it more difficult to lose fat. It's one of those conflicts: often, losing weight helps improve blood pressure, yet the medication makes it more difficult to lose weight. Which way do you go?( I want to be clear that I don't mean to say you CANNOT lose weight taking a beta blocker. It's just a little more challenging and the progress may be slower. )

That's really up to you and your doctor. There are other medical strategies for treating hypertension, but they may not be as effective for you. What I would definitely encourage you to do is make sure your doctor is aware of all of your concerns--fatigue, effect on exercise, etc--and is taking them into consideration when he or she is determining the treatment plan. Often doctors don't think about the daily impact of these side effects--they just know the drugs are easy to take and very effective. So, they are very good for the doctor. After presenting your concerns, the doctor may decide that this is still the best choice for you and that your medical needs outweigh the side effects. In that case, at least you know you weren't just given a "cookbook" response and then you'll have to work with the medication.

Whatever you do, if you are on a beta blocker, do not just stop taking it on your own. When the medicine blocks the receptors (the beta receptors), the body responds by "making" more of them--these are also blocked by the medication, so you don't notice any difference. However, if you stop taking the medication, now all of a sudden you get an "unblocked" response that is enhanced by the extra number of receptors. That's not something you want. Normally, when someone discontinues beta blockers, they do so in a graduated fashion so that the body also "downregulates" the number of receptors.

Hope this helps.

Thanks! That does help and it makes sense.