I am 79, with two episodes of A.F behind me, a few years ago . and arrythmia, for whch I’m taking a betablocker ( Metoprolol along with Eliquis) I am otherwise in excellent health for my age: I windsurf, I exercise regularly and I am an avid runner ( 3 sessions a week of about 5 km).
My doctor said I can, indeed I must, continue to exercise.
AS expected, the first effect of the betablocker is that it depresses the rest h.r. which is now down to 50-55 bpm, from 70-75 before going on medication.
Before going on betablocker, my target h.r for training at my age was 100 bpm @ 70% and 112 bpm @ 80%, but I could easily go up to 130 bpm or more, with little or no strain, because I was well trained.
After going on betablocker, for the same perceived effort intensity my h.r significantly dropped: it barely reaches 100 bpm and if I push it, I immediately feel some strain.
I am a bit confused, because now, for some reasons the pattern changed in the opposite direction : while training with the usual PERCEIVED intensity, my pulse goes up very high, to 160-165 bpm.
Under normal conditions, I’d run to the E.R. as I did the first time, but now I am less worried because I don’t feel any strain whatsoever on the heart. I notice it only by looking at my cardio watch.
I’ll speak to my cardiologist, but I wonder if anybody can comment on this. Can tachycardia by itself affect the heart if there are no symptoms at all?
Thanks
Ittiandro
Hello, Ittiandro.
It's great to hear that you're maintaining an active and healthy lifestyle at the age of 79, even with a history of atrial fibrillation (AF) and arrhythmias. The use of beta-blockers like Metoprolol in conjunction with Eliquis is a common treatment approach for these conditions. As you've observed, beta-blockers can significantly lower your resting heart rate, which is consistent with their mechanism of action.
The change in your heart rate during exercise after starting Metoprolol can be attributed to the medication's effect on your heart's response to physical activity. Beta-blockers work by reducing the effects of adrenaline on the heart, leading to a lower heart rate and reduced force of heart contractions. This can make it harder to reach higher heart rates during exercise, which aligns with your initial observation of a lower heart rate for the same perceived effort.
However, your recent experience of a higher heart rate (160-165 bpm) during exercise without feeling any strain is intriguing. This could potentially be due to several factors:
-
Variability in Medication Effect: The effect of beta-blockers can vary over time, and individual responses to physical activity can also change.
-
Measurement Accuracy: Ensure your heart rate readings are accurate. Sometimes, devices can give erroneous readings, especially during high-intensity activities.
-
Physiological Changes: As we age, the body's response to medication and exercise can change. Factors like hydration, temperature, and even time of day can influence heart rate.
-
Tachycardia and Symptomless Episodes: It's important to note that tachycardia (a fast heart rate) can occur without symptoms and may not always be harmful, especially in well-conditioned individuals. However, in the context of a history of AF and arrhythmias, it's crucial to be cautious.
Consulting with your cardiologist is the best course of action. He/she can assess whether this change in heart rate pattern is a cause for concern, potentially adjusting your medication or recommending further tests. It’s essential to monitor any other symptoms that may accompany these episodes of high heart rate, such as dizziness, shortness of breath, chest pain, or palpitations.
Your cardiologist might also discuss the possibility of undergoing an exercise stress test to evaluate your heart's response to exercise while on beta-blockers. This can provide valuable information on how to safely continue your exercise regimen.