(CNN) — Sighs — those long, exhales of breath often accompanied with a bit of a whimper — have long been seen as a sigh of melancholy, frustration or even despair, leading us to ask the sighing person, “What’s wrong?”

A recent study turns that notion on its head. Instead of seeing sighs as sadness or exasperation, recognize them for what they accomplish — stress relief, said Dr. David Spiegel, a professor of psychiatry and behavioral sciences and director of the Center on Stress and Health at Stanford University School of Medicine.

“People think taking a deep breath is the way to ease stress,” he said. “But it turns out that exhaling slowly is a better way to calm yourself.”

A variety of ways to breathe

You breathe without thinking, but what’s the best way to inhale and exhale while you’re thinking about it — especially if the goal is better health?

To find out, Spiegel and his team conducted a study, published earlier this year in Cell Reports Medicine, comparing three different types of deep breathing with mindfulness meditation. The goal was to see whether a breathing technique might be as effective as meditation in reducing stress.

Researchers sorted 114 people into four groups and asked them to practice mindful meditation or one breathing exercise — box breathing, cyclic hyperventilation or cyclic sighing — for five minutes a day for 28 days.

Box breathing requires a person to breathe in, hold, breathe out, and pause equally (like the sides of a box) to the count of four. In cyclic hyperventilation, a person breathes in deeply and out quickly — the inhalations are much longer than the exhalations.

In cyclic sighing, a person inhales through the nose until the lungs are halfway full, then pauses briefly. The lungs are then filled completely with another breath, and then the breath is slowly exhaled out the mouth.

“You want the exhalation to be like twice as long as the inhalation,” said Spiegel, who is also the medical director of Stanford’s Center for Integrative Medicine.

The team then assessed mood, anxiety levels and sleep behavior after each breathing or meditation session, as well as respiratory and heart rate variability.

Sleep was not affected, the study found. All forms of breathing and meditation increased positive mood and improved anxiety. However, breathing was more effective than meditation, with cyclic sighing making the most difference, the study found.

“Cyclic sighing is a pretty rapid way to calm yourself,” Spiegel said. “Many people can do it about three times in a row and see immediate relief from anxious feelings and stress.”

While interesting, the study was small, and doesn’t take away from all the work in progress on the benefits of any form of breath work or meditation, said stress management expert Dr. Cynthia Ackrill, former editor for Contentment Magazine, produced by the American Institute of Stress.

“We know that bringing your attention to any form of breath work starts the process of awareness that feeds mindfulness and its benefits,” she said in an email. “As long as we are all experimenting with mind-body connections with open minds and finding something that calms us, yay!”

Why breathing works

Deliberately taking a slow, deep breath, holding it, and then letting it out slowly activates the parasympathetic nervous system, responsible for controlling how the body rests and digests, Spiegel said. Heart rate slows, blood pressure drops, digestion is improved and the mind begins to wind down and relax.

Contrast that to a sharp inhale of breath, which you might take when you’re afraid or in danger. That triggers the sympathetic nervous system, responsible for getting us ready to fight or flee.

“The brake works more healthfully than the accelerator here,” Spiegel said. “By slowing your heart when you do this cyclic sighing you’re immediately soothing yourself in a rather rapid way.”

“We believe breathing is a pathway into mind-body control,” he added. “It’s part of the autonomic system like digestion and your heartbeat, but unlike those body functions, you can easily regulate breathing.”

Other ways to breathe deeply

This isn’t the first study on the topic. Researchers have been busy trying out different methods to see which calms the body the quickest, longest, or most deeply, and which gives the most health benefits.

Many breathing methods are borrowed from ancient yoga, martial arts and meditation practices. For example, the 4-7-8 method, in which you breathe in while counting to four counts, hold the breath for seven counts and exhale while counting to eight, is based on pranayama, an ancient form of breath regulation practiced in Hinduism and Buddhism.

There are all sorts of variations: The 4-4 method, in which you breathe in and out for a count of four; the 6-6 method, in which you breathe in and out to the count of six; alternate nostril breathing and many more.

Diaphragmatic breathing, also known as belly breathing, has been practiced for millennia by practitioners of tai chi and yoga. It requires the breath to be inhaled so deeply that it fills the abdomen — you can tell if you’re doing it right by watching your stomach rise and fall.

A 2020 meta-analysis found diaphragmatic breathing is especially beneficial for patients with chronic obstructive pulmonary disease (COPD), and might be helpful in reducing stress and anxiety and treating constipation, eating disorders, high blood pressure and migraines.

You don’t have to sigh or breathe loudly to get the benefits of any forms of breathing, Ackrill said.

“These don’t need to be audible sighs, you can just change the rate quietly,” she said. “And you just might get the people around you to slow down their breathing as well.”

So go ahead. Take a deep breath and let it out in a huge, long, slow sigh. And if anyone does ask what’s wrong, you can smile and say, “Absolutely nothing! I’m just releasing my stress.”

Go ahead and sigh. It’s good for you