Kara Kennedy's Death: Q&A On 'Danger Zone' After Exercise

Kara Kennedy speaking at the funeral of her father, Ted Kennedy.
Kara Kennedy speaking at the funeral of her father, Ted Kennedy.

Kara Kennedy’s wake is to be held this evening, and her funeral tomorrow. She was the 51-year-old daughter of the late Sen. Ted Kennedy, the mother of two and a long-time lung-cancer survivor. She died at her Washington, D.C. health club last Friday of an apparent heart attack, reportedly after her daily work-out.

Her death caught my attention for two reasons. First, the obvious: It was yet another Kennedy death at a tragically young age. The second was more personal: A close relative had just been caught in an oddly similar circumstance.

He’d started feeling woozy and weak right after a work-out, and may have saved his own life by going to the emergency room. It turned out an artery was almost entirely blocked, and he needed a catheterization and a stent. When I mentioned his experience to a colleague, I got an immediate echo: Yes, she said, our co-worker had exactly the same thing happen right after he got off the stairmaster.

Hmmm. Is there a danger zone right after exercise? Why would that be, when the greatest exertion load is already off? I spoke today with Dr. Aaron Baggish, a Massachusetts General Hospital cardiologist and expert on the effects of exercise on the heart and cardiovascular system. (Also himself a competitive runner, and the cardiologist for the Boston Marathon.)

[module align="left" width="half" type="pull-quote"]'Probably 25% of the total workout time should be spent in warm-up and cool-down.'[/module]

His edifying explanations follow, but here’s my own takeaway: I am never, ever going to work out again without allowing time for a cool-down period of at least 10 minutes or so. Constantly feeling pressed for time, I tend to skip the warm-up and shortchange the cool-down in favor of getting in my 30-plus minutes of hard cardio. No more.

Note: This is in no way to imply that Kara Kennedy may have failed to cool down properly. She sounds like she was doing everything right for her health. I'm just sharing what I've learned for myself, and what sticks in my mind most was the case of a man Aaron just saw in the ICU — a fit, middle-aged man who'd just had a heart attack after playing tennis. In a rush, the man jumped right into a super-competitive match, and the minute it ended, he got into his car, where he started having chest pain. The crux of the problem was that he hadn’t had time to warm up or cool down.

So is there a danger zone right after a workout?

The short answer is yes.

The more complete answer is that there’s no question that routine cardiovascular exercise is the best way to reduce your risk of having a heart problem. The paradox here is that if you do exercise, you’re most likely to have your heart problem either during or immediately after your workout.

There are two reasons for that. One is that people are more likely to notice symptoms, particularly of coronary disease, when exerting themselves. The second is that if people are going to have an acute closure of their coronary arteries, exercise can be the trigger for that.

Why would that be?

The reasons that a coronary artery would suddenly collapse or close up is that a blood clot would form at an area of prior instability.

The process of artery-narrowing involves a collection of cholesterol and blood cells in the wall of the artery. Those areas are weak, the artery wall is weak, and so with the stress of exercise, you’re actually likely to rupture those areas and a blood clot will form there.

Is it the extra blood volume of exercise?

Along with the blood volume, it’s the pressure, and it’s actually the adrenaline surge that comes along with exercise that work together to cause this.

But why would it hit after exercise instead of during?

It can do both. It can come after exercise because of all the things we just talked about: high adrenaline state, high blood volume and velocity. They persist for a period of time after exercise, and that’s when you’re in your danger zone.

Is it the danger of “coming down” from the exertion of exercise?

It’s not something additional that could be happening, it’s more that people actually become aware of it after the discomfort of pushing themselves during exercise is removed. If you’re breathing hard on the treadmill or stairmaster, you’re focused on those things unless something really bad is happening, but after you stop and allow your body to recover, people tend to notice that something is just not right.

Can you quantify the greater risk of heart problems during or after exercise?

We don’t have those numbers but the take-home is that the more vigorous exercise people do, the less likely they are to develop heart problems overall. But when it’s going to get them is when they’re exercising. It’s a paradox I deal with every day.

Here are a couple of take-homes:
1)If you exercise routinely, which we all should do, you’ve got to pay attention to your body, and if your body is giving you signs that something is changing or unusual, you need to be aware that it could be the marker of something bad happening.

There are things you can do while exercising to reduce the risk of this happening. It all has to do with what happens on the tail end of exercise. The body does not like sudden starts and stops. We all are at some risk of having a heart problem with exertion. The best way to minimize that chance is to warm up very thoroughly, and more importantly, to cool down thoroughly. I spend a lot of time with all my patients talking about how to do this: Probably 25% of the total workout time should be spent in warm-up and cool-down.

What’s the physiology, that cool-down is so important?

The high adrenaline state and the high blood volume and velocity are the triggers for these ruptures, and the best way to minimize that is to allow the high volume, high pressure and high adrenaline states to slowly diminish rather than stop suddenly.

Could you describe a good cool-down?

It’s a gradual sustained reduction in effort level. The simplest way to think of this is that you think of exercise as a step up, a plateau and a step down. You start from doing nothing, gradually increase your effort over 10 minutes, to the point of actual exercise effort, and then do that same step-down after exercise.

I have to confess, I never have time for warm-up and cool-down, if I’m going to get in the prescribed 30 minutes of cardio...

The only easy answer is to make a little extra time. From a safety perspective, if you really only have 30 minutes, the time to pinch is not the cool-down but the period you spend pushing yourself.

I have two goals: to get the sedentary to start exercising, and to teach the person who’s already making the effort to exercise to do it a little more intelligently. And I’d really encourage people who are exercising to talk to their doctor about it.

This program aired on September 20, 2011. The audio for this program is not available.

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Carey Goldberg Editor, CommonHealth
Carey Goldberg is the editor of WBUR's CommonHealth section.



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