Athletic heart Cycling Wed Healthy Living

Cycling Wed: Athletes with large atria and the effect of exercise on BP

Hi all,

I know; it’s Thursday morning and this is supposed to be Cycling Wednesday. My excuse is a good one. I bought an Iphone 5 yesterday and then became hypnotized by the inanimate object. Time flies with a new Apple product. Bedtime came and I said, “Crap…it’s Wednesday!.”

Anyways, I was scanning the recent AHA’s meeting abstract page and came upon two interesting exercise-related abstracts worth sharing.

The first one was on Left Atrial Size in Elite Athletes. (A side note is it comes from my Medical School–UConn). What the researchers did was perform a meta-analysis on 56 other studies that encompassed more than 6000 athletes. You can click on the abstract for the details but the short summary is that elite athletes have enlarged left atria. Endurance exercisers show the greatest LA sizes. These kinds of studies get accepted at meetings because it’s important for doctors who evaluate athletes to know about athletic variants.

The reason why this study caught my eye is that athletes are clearly at risk for heart rhythm problems, especially atrial fibrillation. We don’t understand exactly why this is, but one of the theories involves enlargement of the heart. It’s normal for the heart to adapt to exercise. We call this the athletic heart. What’s not known, and hard to sort on a patient-to-patient basis is the gray area between normal adaptation and abnormal enlargement of the chambers and muscle walls. The thinking goes that chronically enlarged chambers mixed in with years of excessive and unremitting inflammation (training) in genetically susceptible individuals leads to the athlete-arrhythmia syndrome. We are still learning a great deal about the upper-limit of exercise quantity.

The second abstract involves an issue I see every day in the office. It’s entitled Exercise Training for Blood Pressure: A Systematic Review and Meta-Analysis. 

When faced with high blood pressure readings in the office, it’s important to recommend treatment. High blood pressure is a serious problem. This is not news. The issue is what treatment? The overwhelming majority of the time, doctors prescribe a medicine. And medicines do lower blood pressure. You know my opinion: I think we don’t emphasize exercise and lifestyle enough. That’s why I like abstracts like this one. Again, in another meta-analysis of previously published studies, researchers show that exercise–as the sole intervention–lowers blood pressure. It works.

This is a contentious topic, isn’t it? If things that patients do–not doctors–like exercise and eat right, can control blood pressure than a question arises: What are the roles of patient and doctor in the treatment of high blood pressure? Right now, the consensus opinion is that it’s mostly the doctor’s job. Studies like this one should lead us to reconsider this skewed proportion.


3 replies on “Cycling Wed: Athletes with large atria and the effect of exercise on BP”

You don’t ever seem to run short of interesting ideas to discuss! But if you do–it might be interesting to consider how much exercise is best for people as they get older. I keep reading that 30 minutes a day is good, and then I read that almost everything (gardening, walking, taking the stairs, etc.) counts. So–if you’re over 50? over 60? over 70? over 80? male or female? How heavily, and how much, should you be exercising? And how best to build up to it? How important is it to raise your pulse rate, and for how long, as you get older? And if one exercises more out of duty than because they really enjoy it (sorry, but I am afraid that there are some of us in this category) how do you know when you can feel done?

So, should I do my very best to talk my long distance runner of a son out of his latest kick, running ultras of 100 miles? I, his Mother, had afib for seven years before ablation in 2011. Now I’m worried about him.

The second study (exercise influence on BP meta-study) had a very interesting sub-result:

Isometric resistance exercise (not the kind we do in cycling) had the largest impact on systolic pressure (-10mm); endurance exercise (eg. cycling) was a distant second place (-3.5mmHg), and dynamic resistance the least (-1.8).

Should we advise isometric exercises for people with hypertension?

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