Powerless to help after catastrophic earthquakes struck her hometown of La Guaira in Venezuela two months ago, Maria Medina struggled to sleep.

She was more than 1,500 miles away in Florida, USA – where she has lived for the last 15 years – and was racked with worry for family and friends.

Box breathing helped her combat sleepless nights.

“In moments where I feel that there isn’t much that I can do, like lying in bed at night and staring at the ceiling… I know it’s going to help me,” she says.

The 31-year-old first came across box breathing in 2020. She was studying for a master’s degree while working full-time and the stress of doing both became too much once the Covid pandemic hit.

She sought help from a therapist who showed her how to box breathe.

The technique consists of inhaling for four seconds, holding your breath for four seconds, exhaling for four seconds and then holding for another four seconds before inhaling again and restarting the cycle, says breathwork coach Stuart Sandeman.

“Those seconds can be all sorts of lengths, but they must all remain the same,” he explains. This equal four-step pattern is where the technique derives its name.

Stuart says box breathing is best used before you do something stressful or an event that might cause you to feel anxious, like an exam or presentation.

There’s no set length of time to do it for. Some people feel the positive effects after just a few minutes; others prefer to do it for as long as 15.

Breathwork originated from traditional practices like yoga and has been used in other fields like martial arts for centuries, says Stuart.

But box breathing has become popular in modern times because it can “both focus the mind and allow us to balance our nervous system”.

He adds: “Famously, the US Navy Seals are box breathers. They use it before going into a hostile situation.”

Stuart has also taught breathwork to the England football team.

For Maria, 31, who works as a programme manager for a tech company in the US, she does it before she goes to bed, or when trying to get back to sleep after waking up in the night.

A recent study from North America looking at the effectiveness of box breathing found it could prevent large increases in heart rate and other stress markers in the body among people facing high-pressure situations.

The study, published in the journal Comprehensive Psychoneuroendocrinology in June, was undertaken by academics at Texas State University and the University of Toronto Mississauga.

Dr Helen Garr, a GP who treats doctors and nurses suffering mental health difficulties, says: “I recommend box breathing to lots of my patients because it is one of the most powerful evidence-based hacks that we have to take control of our stress response and our nervous system.”

She says the last step of box breathing, where you hold after you exhale, is what causes the greatest change physiologically.

“What is happening inside our bodies during the final hold is that we are retaining carbon dioxide (CO2) and when our brain detects the increased levels of CO2, it feels panic. We feel that urge to breathe.”

That final hold trains us to better cope with higher levels of CO2 in our system and reduce that feeling of stress, she says. People breathe differently when they’re stressed, which leads to changes in their body’s CO2 levels.

“Box breathing trains us to get used to variations in carbon dioxide in the blood and in the brain and helps overcome feelings of panic,” she explains.

Unlike Maria, Brittany Lamm doesn’t box breathe before she goes to sleep but does so after waking up.

“I do it every morning,” the 28-year-old tells me from her home in California. “I actually did it just before you called me.”

She found out about box breathing online a few years ago when she was going through a difficult time in her personal life and was looking for ways to cope with the stress of it.

Many people who use box breathing, from former soldiers to lifestyle influencers, share tips on how others can use it in their lives. Some also post animated guides for people to follow along with.

“If you wake up feeling anxious, it’s a really great tool to help get you back into your body and out of your head,” says Brittany.

It helps her feel a sense of control over her thoughts and emotions instead of letting them dictate her day.

She found it so effective that she learnt about other breathing techniques and incorporates them into her work as a life coach. She did a degree in psychology and is training to be a licensed therapist.

“I do it with my clients when we start our calls, so that they feel calmer than when they arrived.

“If we’re talking about [emotionally] heavy topics, like what’s going on in their relationship, it makes it a little bit easier for them.”

She appreciates that some people might be sceptical about the difference breathing techniques actually make to stressful situations but urges people to try them.

“Breathwork isn’t a one-size-fits-all. There’s so many different types for whatever you might be feeling or going through.”

She adds: “Nine out of 10 people that I work with say they really do feel so much better afterwards.”

Maria feels similarly and has recommended box breathing to many friends and colleagues who have gone through stressful periods.

Fortunately for her, none of her immediate family died in the Venezuela earthquakes which are estimated to have killed at least 6,300 people.

“But my best friend lost her home and I know people who lost family and friends.”

Sleepless nights still afflict Maria occasionally but box breathing is something she knows can help her deal with periods that might feel overwhelming.

“I think that sometimes we forget to breathe, like really intentionally breathe, and we underestimate the powers that it might bring to our body and mind.”