My understanding is you can push your HR up to the "normal" limits if it doesn't make you so breathless you can't even talk. From the general rule I'd say 80% of 220-46 = ~ 140. This is obviously too high for your condition, but I offer it as a limit imposed by your AFib condition.
I am in permanent AFib, and a past runner, so my interest is more than academic. The advice I get from my cardiologist is I can go to about 140 if I can take it, and I can. I'm 70 years old, so 140 is over 90% of 220-age. Again, how do you feel. As I said, I am a past runner, so my muscle and cardiovascular system has been conditioned to operating at the limits. If I get feeling breathless, I slow down, even sit down.
Your walking about HR of 93/94 sounds about right, especially as you are overweight, you have to do the work to move the weight around. I assume from those numbers you resting HR may be around 80-85, anyway lower than 93.
Give yourself time to work up to a higher HR, but I think you don't have to worry about the AFib in that regard. Think about how you feel, you should not work so hard you get dizzy... or faint.
Thanks for your swift reply, I apologise for not having got back to you sooner.
I returned to the gym today, having had a programme made for me, and tried it out. I haven't been used to doing much exercise in my youth..at that time it was the done thing to wrap us 'poorly children' up in cotton wool and prevent us from doing too much exercise, however in my twenties I did regular aerobics, and so did increase my fitness that way. I was never overweight until I hit 30 and my heart condition had begun to deteriorate meaning that I could no longer do the aerobics and just found pushing my newborn son in his pram difficult. Following my heart surgery I did go to cardiac rehab and to the gym for 2.5 years, at that time I was 2.5 stones overweight, and I lost that weight over the 2.5 years..unfortunately I stopped going to the gym at that point, due to getting divorced and having too much stuff going on in my life as a result of that...I then regained the weight I'd lost, plus more, I'm now 3.5 stones overweight having already lost 1 stone since starting to go to the gym 3 x weekly from the end of February. So I'm not generally an active person as you have been, a runner or anything..
I only managed about half of the programme tonight, due to time restrictions, and found most of it fine. The one thing I did struggle with was the Treadmill. I haven't used the treadmill often recently, due to problems with my right foot, however when I do use it I generally have it set to level 1 with a 1.5% incline, and I walk at 4.0/4.5kph at most, I can do this for around 20 minutes comfortably and my heart rate doesn't go above 117 except occasionally. Tonight I noticed that the gym instructor had set me a target of using the treadmill on Level 6, on a random programme which meant that the incline increased/decreased throughout the time I was using it, and I was asked to walk at 5.0kph for 20 minutes. I only managed 8 minutes at that speed on that setting, my pulse rate rose to over 130 at times and I felt very breathless and uncomfortable. I reduced my walking speed to 4.5 for a couple of minutes then gave up completely. I felt exhausted, out of breath and a little depressed at struggling so much. I know that I may probably have to reduce the speed at which I walk, or the level at which the programme is set, but feel that the gym instructor may think I'm just not giving the programme a chance, as it was my first attempt tonight at the rate he suggested. I don't want to set myself targets that are unachievable for me at present, yet I don't want to appear to be giving up too soon either, I really did feel that I needed a sit down after trying the treadmill tho tonight, and it did put me off the programme a little. I will persevere with the rest of it, but feel I need to speak to the instructor about that one issue.
Thanks for reassuring me regarding my current pulse rate, and the levels that could be reached by me without it being overly dangerous...if you have any further tips for me, I'd love to hear back from you again.