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"How's the traffic?" That's one of the first questions I ask patients who visit my office. But I'm not just making small talk. Being stuck in traffic raises blood pressure and triples heart attack risk. So if a patient has had a tough commute and her BP is elevated, I'll recheck it later. There are other surprising situations and times when the chance of heart attack rises dramatically. If you or someone you know has a history of heart trouble, here's when to be watchful.

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1. First thing in the morning

The risk of heart attack increases 40% in the morning, Harvard researchers estimate.

Why? As you awaken, your body secretes adrenaline and other stress hormones, increasing blood pressure and a demand for oxygen. Your blood is also thicker and harder to pump because you're partially dehydrated. All this taxes the heart.

Protect yourself: Build some time into your wake schedule so you can hit the snooze button and wake up slowly. If you're a morning exerciser, warm up thoroughly so as not to additionally stress the heart. And if you're on a beta-blocker, take it before bed so the medication is at full strength in the am.

2. On Monday mornings especially

Science shows there's good reason to dread the first day of the work week.

Twenty percent more heart attacks occur on this day, probably because people are stressed and depressed about returning to work.

Protect yourself: Relax on Sunday, but try not to sleep in. Getting up early on Monday after sleeping late Saturday and Sunday can raise blood pressure even more because your body is fatigued and its natural rhythms are out of whack. Try to maintain a regular sleep/wake schedule all week.

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3. After an indulgent meal

A 5-course, calories-be-damned dinner can have an immediate impact on your heart health.

Studies show high-fat, high-carb meals constrict blood vessels, making blood more prone to clot.

Protect yourself: If you must indulge, keep your portion sizes reasonable. A daily aspirin will also help prevent blood "stickiness."

4. During a bowel movement

It's the last place you'd want to run into heart trouble, but it can happen.

Straining increases pressure in the chest, slowing the return of blood to the heart.

Protect yourself: Eat lots of fiber, stay hydrated, and avoid straining.

5. During unusually vigorous exercise

Having a heart attack while shoveling snow is a classic example of this.

The heart attack occurs because the victim isn't accustomed to that kind of effort and stress hormones skyrocket, causing blood pressure and heart rate to jump.

Protect yourself: Regular exercise protects your heart. But increase your intensity level gradually.

6. At the podium

From the heart's perspective, public speaking can be similar to unaccustomed exercise.

Extreme nervousness raises blood pressure, heart rate, and adrenaline levels, all of which can make the presentation itself a secondary worry.

Protect yourself: To counter these effects, some of my patients take a betablocker before speaking, flying, or doing anything that makes them overly anxious.

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