"I love you with so much of my heart that none is left to protest."
—Beatrice, "Much Ado About Nothing "
by William Shakespeare

Think for a moment about someone dear to you.

When you declare "I love you," is that purely a statement of cognitive thought? Or simple, heartfelt emotion? A mix of both, one indistinguishable from the other?

Emotions can overwhelm our brains and our bodies. True love rushes. As does anguish. They travel our emotional highway between our hearts and our minds in a beat, the connection undeniable but difficult to measure.

So was Beatrice right? Did she not love with her mind as much as her heart alone?

While there is much still to understand, science already tells us there is no doubt that emotion impacts not only our mental health but also our physical well-being, especially that of the heart.

"A growing body of evidence suggests that psychological factors are — literally — heartfelt, and can contribute to cardiac risk," Harvard's Medical School reported.

A broken heart really can hurt you. But it doesn't have to.

Here's how it works.

Good Stressors vs. Bad

"You love me — then what right had you to leave me? ... You, of your own will, did it. I have not broken your heart — you have broken it; and in breaking it, you have broken mine."
— Heathcliff, "Wuthering Heights" by Emily Bronte

When you exercise, your heart beats faster, your blood pressure increases, your breathing picks up as your lungs work to oxygenate the blood your heart is pumping, energy (sugar) is sent to your muscles.

Through the course of a workout, this controlled exertion is regarded as a good thing for most.

And what happens when you receive devastating news, such as the death of a loved one?

Your heart beats faster, your blood pressure increases, your breathing picks up.

Similar reaction. So why is one good for you and the other not?

It's the suddenness.

"The heart does not have time now to adapt to the necessary changes it needs to withstand this stress," said Dr. Krishna Sudhir, divisional vice president, Abbott Vascular. "The heart begins to race without necessarily a compensatory increase in blood supply. And when the news is very serious, the interaction between the heart and the brain tends to be at its worst."

Our hearts are innervated, meaning many nerves supply it. Some slow it down; they're activated when we relax or meditate. Others turn on when we're under emotional stress, causing the heart to quicken, ready for fight or flight.

For example, researchers from Duke University reported in the American Journal of Cardiology found that during the stock market crash from Sept. 2008 to March 2009, heart attacks steady increased. The bleak financial news was just too much for some to take.

Dr. Sudhir cited a recent study from Massachusetts General Hospital that looked at the connections between the brain and the heart.

"The study suggested that activity if the amygdala — an olive-shaped part of the brain deep within the emotional cortex — is overactive, your future risk of having a heart attack or stroke over the next three to five years is actually much higher," Dr. Sudhir said. "As cardiologists, we've always known at some level that there's a connection between emotions and heart disease. But when you see scientific data demonstrating the link, the point is actually being proved in a very direct way."

The Dynamic in Men, Women and Children

"The reason it hurts so much to separate is because our souls are connected."
— From "The Notebook" by Nicholas Sparks

How do gender and age impact how the heart responds to emotion and the mind? In ways you might imagine — and some you might not. As Dr. Sudhir explains, symptoms of heart issues play out very differently among men, women and kids.

In men, heart disease — or more specifically heart attacks — tend to be quite dramatic, taking a page out of Redd Foxx's act as Fred Sanford: chest pain, clutching the chest, pain radiating to the left arm and so on. A man suffering a heart attack or symptoms of heart disease tends to be more obvious.

In women, they and society often ignore their symptoms more so than in men. Women can feel fatigued, unable to complete routine activities. Women's symptoms tend more toward the subtle, which helps explain why women tend to present later in life with heart disease.

According to Dr. Sudhir, studies have suggested the sexes process happy and sad thoughts differently: "Particularly sad thoughts. The response may actually take longer to dissipate in women than it does in men. Anxiety and depression show a higher prevalence in women."

Adults also tend to internalize problems and find themselves alone more. These factors can compound risk factors in adults.

"Emotional issues are often intertwined: people who have one commonly have another. For example, psychological stress often leads to anxiety, depression and can lead to social isolation," Harvard reported through the Patient Education Center. "When combined, their influence is compounded."

Life experiences in childhood may predict future mental health.

"We were all children once, and stressful experiences in childhood may lead to physical and emotional issues in adulthood," Dr. Sudhir said. "Children can develop resilience but need supportive family and school environments, good pediatric care and adult advocacy."

Sad Hearts, Broken Hearts

"The heart dies a slow death, shedding each hope like leaves until one day there are none. No hopes. Nothing remains."
— Chiyo Sakamoto, "Memoirs of a Geisha" by Arthur Golden

Dying of a broken heart.

It's a common refrain when spouses married for decades pass in short order, often within just months, days and, in some cases, hours.

June Carter Cash and Johnny Cash. He passed four months after her.

The parents of Doug Flutie, the Heisman trophy winner, died within an hour of each. Following the father's heart attack, the mother suffered one too.

Most recently and perhaps most famously, it was the rationalization offered when actress Debbie Reynolds followed her daughter, actress Carrie Fisher, the next day.

They all died of broken hearts.

It can feel like futility when we try to explain the unexplainable. But is there a reasoned explanation, based in any scientific fact?

"Yes, indeed," Dr. Sudhir said.

Please explain.

"Sad Heart Syndrome refers to when you're depressed, you put your heart under quite a severe degree of strain. Depressed people are more likely to develop heart disease.

"Broken Heart Syndrome is a more sudden version of this, when you're under severe emotional distress; for example, hearing about the death of a relative. The coronary arteries may go into spasm. There may be decreased blood supply to the heart. The heart might not contract the way it is supposed to."

Stress hormones, particularly norepinephrine, may flood the circulation. This predisposes the heart to rhythmic disturbances, which can end up being fatal.

Dr. Sudhir said Japanese cardiologists have studied the phenomena extensively. They've even given it a name: Takotsubo, which is an octopus trap or catcher.

"When you take X-rays of the heart in people who suddenly heard bad news, the main heart chamber (left ventricle) balloons up and appears bloated like a fish. This is one pathological basis of the Broken Heart Syndrome," Dr. Sudhir said.

When doctors record electrocardiograms of the heart under this kind of stress, it can resemble a heart attack. In fact, the heart muscle has suffered physically from the emotional insult of bad news.

Making the Connection Work for You

"My reason for life. Not living, but life. That was the touch. And she was his reason for life, and why he must survive."
— From "Atonement" by Ian McEwan

Even as science parses out the physical connections between our hearts and minds to delve deeper into this relationship between the two, this much is beginning to be understood:

• We believe we can influence the brain-heart relationship positively through exercise, meditation, relaxation techniques and so on.
• Just as depression can take its toll on your heart, happier people tend to live longer and have fewer occurrences of heart disease.
• Restful sleep helps.

Dr. Sudhir sees a day when psychologists and psychiatrists are integral contributors to cardiology clinics, just as nutritionists and dietitians are often part of a patient's rehab.

He also has some advice.

"The most important aspect is maintaining work-life balance. We emphasize this at Abbott. Most of us have interesting and challenging jobs that keep us excited at work. But there comes a time when you have to turn off and go home and relax, spend time with family and friends, and make sure that we have down time, that relaxation time."

Taking stressors home can harm us from a cardiac point-of-view, he said, and keep us from being at our best at work the next day.

As Dr. Sudhir says, we're just "scratching the surface" of understanding the role emotions play in heart health. But as science digs, it's becoming clearer the long-term impact can extend out to the rest of our lives, including our ability to live our lives to their fullest.

"Love. The reason I dislike that word is that it means too much for me, far more than you can understand."

— Anna Karenina, from the book of the same name by Leo Tolstoy