I had the pleasure of giving a talk at UCSF last week.  The talk was part of the “Cycling to Health” series, which is one of the UCSF Osher Mini Medical School programs offered to the general public.

The talk was videotaped and will be uploaded on the UCTV network in a few months, but I thought I would summarize here for you the main points that I addressed.

In the first part of the talk, I described the normal cardiac adaptions to high intensity cycling, and I made some comments to distinguish cycling from other sports and other endurance sports.

Cycling is considered a sport with high dynamic as well as high static stress.  This causes the cardiovascular system of cyclists to adapt in some major ways.  In fact, there is some data to show that cyclists have the biggest hearts among all athletes!Read more

Dr. Larry Creswell recently wrote a blog post summarizing the excellent research work that he and his colleagues have conducted to better understand the causes and conditions of death during triathlon events.

They have identified all triathlon fatalities that occurred during a 31-year period (1985-2016) and analyzed as many of the relevant factors as possible.  Their work was published in the journal Annals of Internal Medicine.

They observed the following:

• Average age was 47 with a wide range, but the risk of death increases dramatically with age.
• Most victims were male (85%).  This is also the case among marathon fatalities, as we saw previously.
• About 40% of victims were fist time participants, and none of them were elite triathletes.
• Almost 75% of fatalities occurred during the swim event, frequently within the first few minutes.  No specific swimming condition (e.g., water temperature) could be identified.
• Many of the biking segment deaths were traumatic in nature.

In many cases of non-traumatic death, preexisting heart or vascular disease was discovered at autopsy.  The article notes that:

“A surprising and important observation of this investigation, on the basis of autopsy reports, was the high frequency of clinically silent cardiac abnormalities (present in about 50% of the cases with an autopsy report available) that may have caused or contributed to sudden cardiac death.”

Dr. Creswell recommends that athletes should consider their heart health before participating.  Middle-aged men in particular should consider undergoing cardiovascular screening ahead of the event.  Read his excellent blog here.

-Dr. Accad

Discover Our Unique Cardiovascular Health Services!

I have just returned from attending a course on the “Prevention of Sudden Cardiac Death in Athletes,” hosted by the University of Washington medical school in Seattle.  It was a terrific conference at which academic leaders in the field gave updates on the latest research.

Dr. Aaron Baggish, from the Massachusetts General Hospital in Boston, summarized two recent studies that have persuasively shown that coronary calcifications are more common in long-term endurance athletes compared to more sedentary controls.

When the studies were published this past summer, Dr. Baggish was asked to write an editorial commentary to share his perspective.  That editorial was provocatively subtitled “Hearts of Stone.”  The phrase refers to the appearance on CT scans of hearts with heavily calcified arteries as shown in this image:

Calcium in coronary artery detected by CT scan.
Image attribution: Wikimedia Commons

Background

In the last several years, a few reports were published suggesting that endurance athletes may be more prone to having build-up of plaque and calcium in their coronary arteries.  Those reports presented a paradox, because we also know beyond any doubt that regular, moderate level exercise promotes cardiovascular health and longevity.  The studies raised the concern that exercise could be harmful after a certain point.Read more

Image attribution: “MF-180” by Pascal. Licensed under CC BY-SA 3.0 via Wikimedia Commons.

The topic of the pulse rate is one that our patients and healthy athletes frequently bring to our attention.

With the increased availability of wearable monitors, the optimal exercise heart rate has become an almost universal subject of conversation, not only in the athletic community but also among those who are just embarking on an exercise program.

In general, people are interested in the pulse rate in 2 situations:  the resting pulse rate, best measured upon waking in the morning, and the pulse rate during sustained aerobic exercise, such as running or cycling.  Today we will address the pulse rate during exercise and leave the resting pulse rate for a separate article.

So what is the physiologic meaning of the exercise pulse rate?  Is there a pulse rate one should aim for?  What if the rate falls outside the target zone?  Can the pulse rate ever be a clue to a cardiovascular problem?  Let’s take these questions one by one.Read more

Image attribution: Julian Mason/Flickr.

Professional athletic trainer and sports journalist Ian MacMahan asked us that question as part of an article he published in The Atlantic Monthly magazine.

McMahan reported on recent research that raises concerns about ultra-endurance sports carried to an extreme level for many years.  Such an exercise regimen increases one’s chance of having arrhythmia, such as atrial fibrillation, and may also cause scarring in the ventricle of the heart.

Some cardiologists have sounded alarm bells, comparing such exercise regimens to a “toxin.”  In my opinion, it is not yet clear if long-term, high-intensity exercise alone is the cause of the problem, or if those affected have other factors that come into play.  Nevertheless, the research should not be dismissed.   Here are some highlights:Read more

Last Sunday, an experienced marathon runner in his mid-50’s collapsed a few yards from the finish line during the Road2Hope half-marathon in Hamilton, Ontario.  Regrettably, the paramedics were unable to resuscitate him.  This unfortunate story illustrates the rare but tragic phenomenon of exercise-induced sudden cardiac arrest.Read more