Sunday, January 12, 2014

Athletes, AF, and Heart Rate Monitors

I haven't run much since late September. Instead I've chosen to focus on climbing, and on increasing strength in areas of my legs that feel weak and present with chronic tightness. As a result I'm not in tip-top running form. On December 24th I went for an evening run. It was already dark outside. My plan was to keep the pace easy and run a few miles on the lighted streets in town before heading into holiday eating binge season.

As I ran up the first hill, less than a quarter mile from my house, I was completely breathless. Struggling to keep my form and stay relaxed, I slowed the pace to a crawl. Two miles, and a long time later, I still wasn't warmed up. My arms and hands were cold and I wasn't sweating. My heart, beating wildly, felt like it was going to leap from my chest. Something was wrong. I walked the last half mile back to my house.

After showering to warm my chilled body, I strapped on my heart rate monitor. According to the monitor my pulse was fluctuating wildly and hovering above 100, even at rest. My resting pulse rate is normally in the mid 40's. Sitting still with a resting pulse two and a half times my normal rate left me short of breath. Standing up made me dizzy. My heart pulsed rapidly, and I could see and feel the beating through my lower left chest wall.

I'd had this feeling before, but never during cold weather, and never before a run. Sometimes after hard running races or workouts, during hot weather, I've had heart palpitations. Normally they go away by the end of the day. While they didn't seem quite normal, running your body nearly to exhaustion isn't quite normal either. I thought it might be some sort of recovery response to my extreme efforts. I'd also had the feeling one other time - during hot weather in the Cascades. I thought I might have had heat stroke. I didn't cool down for hours after finishing a long, fast hike.

I went to bed, hoping the feeling would subside overnight. The following morning my heart rate was still high - about 110 beats/minute at rest. That evening (Merry Christmas Ryan!) I checked myself into the emergency department at my local hospital. They take cardiac issues quite seriously. I was admitted and given an EKG immediately. The EKG showed an arrhythmia called atrial fibrillation.

Atrial fibrillation, the most common type of arrhythmia, occurs when the electrical pathways controlling how the heart pumps are interrupted or scattered as they travel across one's heart. This causes uncoordinated contractions, especially in the top chambers, called atria. The lower chambers, called ventricles, do most of the circulating, and have to work extra hard when the atria don't help out. A-fib or AF, as it's often called, is a serious issue. Anytime blood stops flowing smoothly it can clot. A clot in the atria could cause serious heart problems. If the clot is ejected it could cause a pulmonary embolism (a clot that attaches itself to the surface of the lungs), stroke (a clot in an artery in the brain), or thrombosis (blockage of an artery and eventual tissue death). These are life threatening and need to be taken seriously.

I was monitored while the ED doctor consulted with a cardiologist. The doctor briefly explained AF to me. It's not common in younger individuals (it affects about .5% of the population), stress, alcohol, and stimulants (caffeine) can trigger AF, and there are treatments that are effective, especially when you're young and there are no other cardiovascular issues. Afterward I was given the OK to go home, on the conditions that I would see a cardiologist ASAP.

On December 27th I met with a cardiologist who confirmed again that AF was my problem. I was going on day 4 with a resting heart rate of about 90-105. He scheduled an echocardiogram (an ultrasound of my heart) and a procedure called cardioversion to electrically reset my heart (like an automated external defibrillator does).

I took the entire four days in stride and tried not to worry. After all, people can live with a slightly higher than normal heart rate, and drugs can be used to prevent clotting, control your rate and convert your rhythm. However, the thought of living without exercise scared the shit out of me. I can live without running competitively. Honestly, I could probably live without running at all. Climbing though, that's a completely different story. All of my friends are climbers, my partner is a climber. It's what I do for work. It's one of the things I love most about life. In a way it seems so silly and vain, but it's reality for many of us as climbers - we participate in all-encompassing activity that becomes a huge part of who we are as people.

In the weeks following this paroxysmal AF I've learned a lot about my heart's little issue. My rhythm has returned to normal, and my resting pulse rate, measured using a heart rate monitor, is around 46. I've spoken with my mother and maternal grandfather about this too. It turns out my grandfather and all of his surviving siblings (4 of them in total) all have AF. There's a good chance it will show up in my mom's siblings as they reach old age too. There is some evidence that AF, which is not well understood and not attributable to any single gene, is familial.

Here is where things get a bit strange though.  It isn't random, although the people that get it are usually predisposed to it. There are triggers for AF. Stimulants can trigger paroxysmal AF. I drank a lot of coffee. Check that box, Doc. Alcohol is a trigger too. I like beer, and probably drank too much. Check that box too Doc. Both sodium and potassium imbalances can trigger AF. After big exercise days I've had bad muscle cramps. I'm not talking about little cramps, I'm talking about hamstrings staying locked, rigid, and bulletproof for up to five minutes at a time. Check another box on the ol' list. Endurance athletes are 5-10 times more likely to get AF than the broader population. This is not well understood, but it's believed that fibrosis, the thickening of of cardiac tissue as a response to extreme amounts of exertion, may create additional electrical pathways that divert the heart's normal electrical signal. Oops. Put another check box on there. A lack of sleep, or sleep disturbances can also trigger AF. I'm not the most normal sleeper. I've always tended to do short nights (5-6 hours) several times in a row, knowing that I could catch up at some point later on. Check another box there Doc. Add in the fact that I have a familial predisposition and it becomes apparent that AF may rear it's head early in my case.

I've begun running again, and I feel normal. Understandably, I'm going to approach racing a bit more cautiously from now on. I've cut way back on my coffee consumption. I now have one cup of half-caff in the morning, and decaf after that. The same goes for alcohol. A few nights each week I'll have a single drink. Over the past year or two regular sleep has become more important (and enjoyable) and I strive to get anywhere from 7 to 9 hours each night. I've begun drinking more water, and in conjunction with much lower alcohol and caffeine consumption, staying hydrated is easier.

In a way, the whole ordeal was a good thing, I needed to be more careful about how I treat my body, especially because sports are an essential part of my life. The decision was easy. In order to continue doing the things I love as long as possible I needed to change my habits. I feel better and I don't really miss the extra coffee and beer. Besides, I'm spending a bit less money now that $10 microbrew 6-packs pass through my hands very slowly.

AF was pretty easy for me to identify because I have no other health issues that might present similarly. However, if you've had panic attacks, anxiety or chest tightness as a result of stress, AF might feel the similar to them. A heart rate monitor, one of my really useful training tools, confirmed my suspicions and might not be a bad tool to have in the box if you're into endurance training and racing. From now on I'll be paying much closer attention to how I treat my body before and after exercise, and everywhere in between.

As usual, I feel like I'm left with more questions than answers. How many other endurance athletes have had this feeling before? Are there others who've been in my position and done nothing, knowing the feeling would subside? How healthy is extreme endurance training? Is it really good for us, or is it actually shortening the working lifespan of our hearts? Everything in moderation, and abstinence in certain things (like alcohol) seems like a very good idea to me now.

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