The resident cardiologist for Prevention Magazine, Arthur Agatston, MD, said that the first question he asks patients when they walk in his office is “How’s the traffic?”

It’s not small talk but a valid medical query. 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, he’ll recheck it later in the appointment. 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.

The risk of heart attack increases 40% in the morning, Harvard researchers estimate. 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 and build some time into your 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.