YOUR HEART POUNDS, YOUR MUSCLES TENSE, AND YOUR BREATHING QUICKENS. Whether you worry about an upcoming test or your job, a stressful situation triggers a cascade of stress hormones that produce such physiological changes.

We often forget that stress can be a powerful and positive thing. It helps keep us alert, motivated, and ready to get out of harm’s way. Do you remember how the stress of an upcoming exam allowed you to work harder and stay awake longer?

If a wild animal chases me, my acute stress response will hopefully temporarily turn me into the sprinter Usain Bolt. But stress over long periods is detrimental to our health and well-being.

Today, we explore how stress affects our biology, before turning to my unusual ritual to help me cope with it.

Stress — Acute versus chronic

Your body’s autonomic nervous system regulates your breathing, pulse, vision changes, etc. This system revs up your stress or “fight-or-flight” response, helping us cope with stressful situations in the short term.

On the other hand, if you experience chronic (long-term) stress, this continuous activation of your autonomic system causes damage to your body. The result? Adverse emotional, behavioral, and physical symptoms.

Chronic activation of the stress response impairs health in several ways. With long-term overexposure to cortisol and other stress hormones, you may suffer from numerous disorders, including:

• Anxiety
• Depression
• Digestive problems
• Headaches
• Muscle tension and pain
• Heart disease, heart attack, high blood pressure, and stroke
• Sleep problems
• Weight gain
• Memory and concentration impairment

The physical manifestations of chronic stress may include achiness, chest pain, or the feeling that your heart is racing. You may have headaches, higher blood pressure, changes in sleeping, and exhaustion.

Some chronic stress sufferers have digestive problems, muscle tension (I used to experience jaw clenching), a weaker immune system, or trouble having sex.

Associated behavioral issues can include too much alcohol consumption, overeating, gambling or other compulsive behaviors (such as shopping or internet browsing), smoking, and illicit drug use.

Stress — The power of a smile

Those of us in the United States smile a lot, perhaps too much (according to non-American friends). So here is my secret weapon to reduce stress — I smile.

As I smile, my brain releases feel-good hormones known as endorphins. Endorphins are our natural pain relievers and can give your mood a boost, too. Those positive vibes during sex? Endorphins. Feeling good while laughing with friends? Yep, you just got a rush of endorphins.

Endorphins are endogenous opioids, a group of protein chains known as peptides. These substances are primarily controlled and released by our brain’s hypothalamus and pituitary gland.

Let’s break down “endogenous opioids.” Endogenous means from the body, and morphine is an opiate pain reliever.

I use a broad smile to trigger a flood of endorphins. I almost always feel refreshed and less anxious after smiling. My stress level is dropping at the moment.

Smiling and stress reduction

By smiling, I may be tricking my brain into thinking that I am happy. University of Kansas (USA) researchers examined how different types of smiling, and the awareness of smiling, affects the ability to recover from stress episodes.

Did you know that there are two general types of smiles? A standard smile utilizes the muscles surrounding our mouths. On the other hand, a Duchenne smile engages the muscles surrounding the mouth and the eyes.

The Duchenne smile is the one that causes the corners of our eyes to wrinkle up with crow’s feet. Some argue that this smile form represents the most authentic expression of joy.

Publishing in 2012 in Psychological Science, researchers Drs. Tara Kraft and Sarah Pressman showed some positive benefits of smiling in a randomized clinical trial. The investigators studied 170 subjects who held chopsticks in their mouths (to create a Duchenne smile, a standard smile, or a neutral expression).

They asked half of the participants in the smiling groups to smile (the other half got no instructions linked to smiling). Here are the results:

All smiling participants (whether they were aware of smiling) had lower heart rates during stress recovery than the neutral group. The Duchenne smilers had the most positive response, by a small margin.

Those in the smiling group who did not get clear instructions to smile had less of a positive effect during their performance of a stressful task (compared with the neutral group).

The study authors concluded that there are psychological and physiological benefits to maintaining positive facial expressions during stress.

So if you are stressed or a bit down, try smiling. Fake it until you make it; you may reduce your level of psychological fatigue.

Before we go, let me share with you some of my other tricks for dealing with stress (I am an oncologist, after all):

• Relaxation response. I meditate each day and do deep breathing exercises as well. I also like to visualize tranquil scenes.
• Physical activity. Movement is my go-to for stress reduction. My daily walk at noon is something to which I always look forward.
• Social support. I need to do better in this domain, but friends can provide a life-enhancing social net and improve longevity.
• Practice gratitude.

Please seek medical attention if you feel overwhelmed, have thoughts about harming yourself, or if you are using drugs or alcohol to cope. Thank you for joining me. Did you notice my broad smile in my profile photo?