If you like thinking and writing, few topics are better than the excess exercise and heart disease story. Indeed it is a matter for the curious.
Two studies published last week in the British journal Heart addressed the relationship of exercise and heart disease. (See references below.) Although these studies garnered mainstream media attention they added little to what is already known. Namely, that moderate exercise is protective and excessive exercise is detrimental. This has been dubbed the J-curve of exercise. You could also call it…obvious.
I’ve been to this place so many times, I was going to leave it alone this time.
Two things changed my mind.
One was a series of comments on my Is Atrial fibrillation Necessary post on theHeart.org. The post describes the fact that lifestyle factors, not bad luck, play a central role in atrial fibrillation and its treatment. I believe this research, from scientists in Adelaide Australia, is the most important work in all of electrophysiology.
The Australians are exposing our blind spot. Their findings force us to look at AF as a modifiable acquired disease. Modifiable not with drugs, or freezes, or burns, but with simple lifestyle choices. What we eat, how we sleep, how much weight we carry–these are the things that matter to the health of our atria. What makes the Australian work so compelling is that they connect basic science and physiology to real-world clinical outcomes.
It’s important to note that the Adelaide brand of lifestyle intervention is aggressive. They enroll overweight patients in a physician-led clinic where multiple areas of health are addressed. These patients get results. Their weight drops, BP falls, sleep improves, blood sugar decreases, alcohol intake plummets. Through these anti-fibrillatory effects something else happens: they feel better. Go figure.
So, yes, the Australians are reversing AF in a population that is over-indulged.
Many of the readers here are endurance athletes. And when viewed from a distance, athletic people do not appear over-indulged, eg, they are not overweight. This sort of thinking came through in a number of the comments on my THO post.
“There are some skinny normal-BP people with AF and no valvular defect. Lifestyle modification will help many, but not all.”
And this one:
“Strange thing is though, a remarkably high level of “super fit” people get Afib too…”
Can you see the intuitive (fast) thinking? That skinny and athletic equates to “healthy.” Most doctors, those who don’t roll with the athlete crowd, think this way.
I, and most of you, know better. Many, if not most, masters-aged athletes are completely and utterly, micro (last few weeks) and macro (last few decades) over-indulged. We’ve been at the train-like-Lance-ride-like-Lance game for a lifetime. Exercise is our drug. When we don’t race fast, we train more, not less. A brisk 10K run isn’t enough, we need to run a marathon, then two, and of course, many, like I once did, move to triathlon. Always more inflammation, not less.
The steady stream of athletes I care for in my AF clinic are far from healthy. Sorry about the cliché but it’s important here to see more than the just the tip of the iceberg. Consider that only a select few middle-aged athletes are trust-funders who have the entire day to rest and recover from a training session. Most athletes add their over-training to a job, marriage, and parenting. And then there is perhaps the biggest misconception about the non-obese older athlete: they got that way with a good diet. This is rarely true. Many of these folks deal with the pangs of intense calorie depletion by gorging on insulin-spiking carbohydrates, including carbs-with-alcohol. Again, more inflammation.
Now to the second thing that pushed me to revisit this worn canvass.
Last week at the 2014 Heart Rhythm Society Sessions in San Francisco, a group of researchers from Barcelona Spain reported a study that confirms the athlete-is-over-indulged thesis.
This group was interested in how the dose of exercise relates to the risk of atrial fibrillation. Previous work suggests that long-term endurance exercise increases the risk of getting AF (over the general population) by a factor of five. The studies that show this are often criticized because they are retrospective and observational in nature. Many experts have trouble believing that sportsman could be anything other than healthy. So the Spanish team enrolled 115 cases of athletes with AF and compared them to 57 age-matched control subjects. They did regression analysis (statistical way of looking for relationships) on the two groups. They found interesting odds ratios (OR):
- OR for height: 1.06 (Tall people were 6% more likely to have AF. I see this often.)
- OR for obstructive sleep apnea: 5.04 (Subjects with sleep apnea were 5 times more likely to have AF.)
- OR for cumulative heavy sport activity (>2000 hours): 4.52 (This was quite in line with previous research.)
- OR for sedentary individuals: 3.85. (Again, we knew sedentary is bad–see Australian work.)
The most striking finding came when they compared the AF risk of heavy exercisers with ‘normal’ (light to moderate) exercisers. Here they found a nearly six-fold fold increase in odds for AF (OR = 5.89) in the heavy exercisers.
To the group of regular doctors at the Heart Rhythm Society meeting, the researchers emphasized the well-known J-curve of exercise, where light to moderate exercise protects against AF and heavy exercise increases the risk.
But I ask you to move into slow-thinking analytical mode. Did you notice that over-indulgence in endurance exercise exposes one to the same AF risk as being an overweight sleep-apnea patient? Did you see the obvious:
That skinny and athletic are not necessarily healthy. And that AF is a disease of excess–of always being on the gas.
The reason this message is so important is that failure to see the big picture means patients are exposed to serious risks of treatment. I like to tell patients with AF that the disease gets most scary when doctors get involved.
But this wouldn’t be the case if we stopped seeing AF as a disease that always required treatment with drugs or procedures, but rather a disease amendable to good old common sense.