atrial fib, sleep apnea, and overheating during exercise

[Diane321]

I've been reading about both atrial and sleep apnea; I have both problems.  I've thought that the atrial fib was caused by the sleep apnea, but I read today that it could be the other way around. Can you clarify this for me?

I'm an active person (exercise every day), but I need to lose about 80 lbs.  I understand that the weight problem probably caused both problems.  However, two days ago, I exercised and did yard work in high heat and humidity for about 4 hours.  I flipped into atrial fib, and stayed there for about 30 hours.  Could this episode be related to the heat/humidity?

I'm losing weight, work w/a personal trainer two days a week, do water exercises 2-3 times a week, walk, bike ride, and generally stay active every day.  

Thanks in advance for your response.

[Thyguy]

I have had heat intolerance with exercise but only increased premature contractions.  Have you had your thyroid checked.  Turned out I had Graves Disease.  Have TSH, free T4 and TSI, TPO antibodies checked.  I was hyper thyroid but I understand Hypo thyroid can also affect the heart.  A consultation with your M.D. may provide more specific recommendations.  
Best of Health and keep up the good work in taking responsibility for your weight loss.

[Sweetwaterguy]

  There seem to be a number of "triggers" to atrial fib.  It would seem likely that exercise/heat/fatigue could certainly be a contributor.  It is good you are working withn a personal trainer and he/she might be able to advise you regarding limits.  If not, a consult with your doctor may give you the needed information.  
   Good luck on your weight loss program.  You sound committed.