Up front, I’m NOT looking for medical advice. I need training advice and whether I can make TR work for me with my prescription.
I’m a 63 year old male, mostly competing on gravel, riding 10-15 hours a week. Developed atrial fibrillation in the spring. AFib presented at the beginning of races this year when I was full gas to stay with the group. Now on Flecainide and my max heart rate is down to the mid-150s from 175. At threshold (3 w/kg) it’s steady in the upper 140s. (I found my FTP with the Kolie Moore protocol, confirmed with AIFTP.) But no more aFib, at least.
Based on the research I’ve seen, there seems to be a risk of higher intensity efforts being pro-arrhythmic so I believe I should avoid threshold and above. How should I adjust my training in general and is it possible to use TR even though it prescribes over/unders and VO2 max workouts, which I won’t do? I’ve paused my TR subscription in part because of this and in part because I’m mostly riding endurance outside now.
I’m a diesel so I mostly do 60-100 mile gravel races with an occasional 125-200+ miler. I haven’t been able to find anything relevant online and my next-to-last resort, ChatGPT, says to work on fatigue resistance and don’t go above tempo or low sweet spot. No threshold, no VO2 or above. Ever.
(Side ex phys question: if my max HR is suppressed by the Flecainide, can I even achieve a level of intensity that would elicit VO2 max adaptations?)
I’m particularly interested in hearing from coaches who have had athletes in this situation. Thanks for any advice.
Not a doctor or coach, just an opinion on the internet. IMO the ChatGPT advise seems wise.
If i was in your shoes I would build a plan with low sweet spot as the highest effort work, then adjust how frequently I ride sweet spot or tempo based on my physical response and recovery. I would start 1x a week followed by a full rest day. Then layer lots of endurance to fill the rest of the plan.
I experienced a couple of episodes of AFib about a year ago. I got prescribed Blood thinner (Pradaxa) and a beta blocker (Bisoprolol) to be taken if I experience any symptoms of AFib. I have seen other positive effects of Bisoprolol like lower blood pressure, calmer less stressed etc. so I have basically been taking it regularly. The only exception is the day before a VO2max workout, if I had one planned.
I haven’t had any issues doing SST nor threshold medicated, other than my heart rate zones being way of (10-15 beats lower).
During the last year i have done Sustained Power Build back to back a couple of times as I have seen steady progress, despite being 60+.
We are all individuals, but my experience says it is possible to combine AFib with intense training. You should of course discuss this with your doctor. Mine have been very supportive of me training as usual so there’s an fair possibility for others.
You really need to talk to whoever is prescribing your flecainide about this.
Flecainide can cause life-threatening arrhythmias at higher heart rates, in the occasional unlucky predisposed person.
Hence why I’d tell you that ChatGPT or Internet forums are not a wise place to seek advice on this. Bad advice leads to you dying, and you likely lack the expertise to be able to safely judge what is and isn’t bad advice here.
Historically there had been some discussion about doing exercise stress tests in people on flecainide and as long as your QRS didn’t widen out at high rates, it wasn’t felt to be a concern.
I’m not sure how commonly this is done IRL, because this is outside my area of expertise, and because the rate of this is quite low overall.
It’s not clear to me that avoiding higher intensity efforts would be sufficient to avoid the risk of sudden death if you are predisposed.
The person prescribing you the flecainide is the person who needs to be able to answer the question on if you need to modify your behaviors to be safe while on it.
Thanks. My cardiologist is a Cat 3 so fully understands what I’m doing. He’s OK with me doing extended threshold efforts if I’m diligent about electrolytes and hydration but I’d like to avoid them out of an abundance of caution, hence the question about adapting training to avoid them.
I don’t really have an opinion here mainly because I am NOT qualified to do so. But when I had aFib my cardiologist just said to stop if it started causing me trouble. Mine seemed to cause me trouble regularly for a month then not much at all for a month. I could never really make sense of it. It made it very difficult to progress my fitness although I still managed to slowly.
I ended up getting an ablation as I have a very low resting heart so beta blockers weren’t an option. The ablation seems to have worked perfectly and as such I’ve put a very good and consistent 6 months of training together and am really starting to see the benefits.
It sounds like your doctor basically told you that you can train normally. You’re not gonna get better personalized training advice than that, off the internet.
If you’re imposing additional restrictions on yourself for personal reasons, you will need to tell us what you’re personally willing to do before anyone could give suggestions.
No one here is going to be able to give you better advice on what’s safe for you to do, given your specific health problems, than your doctor. So I don’t think you should expect to get that information here.
FWIW as a long standing AFib sufferer it’s the repeated long endurance work (ie the diesel stuff) with elevated HR that leads to Afib, and you may find shorter more intense workouts with proper rest leads to less arrhythmias.
I did manage to train, race Zwift & play competitive field hockey fine on flecainide for approx 3 years until the drug ended up causing more issues than it solved for me personally, so keep an eye on your resting HR and other metrics. Now the drugs don't work, they just make you worse - Greg Hilton's Website