Two miles off the coast of Ft. Lauderdale, far past the shallow reefs speckled with colorful swimsuits and snorkeling tourists, the 42-foot, glass-bottom boat glides to a stop. The water here is deep—570 feet, to be exact—and a bit choppy, but otherwise perfect: denim blue, with shimmering waves that dance in the morning sun. A jagged horizon of A1A beach resorts is still visible to the west, but in the other direction, there is nothing but endless miles of ocean.

Onboard, a handful of dive students make last-minute adjustments to their wetsuits, pulling masks over their eyes as they pad their way toward the back of the boat, where they will soon descend into the lapis water. Their instructor enters first, followed a few moments later by the first student, JP Quirino, 36, a tall and athletic general contractor from North Miami.

The deck is littered with extra weights, spare fins, and other diving paraphernalia, creating a scene you might expect to see on any dive boat, anywhere in the world—with only one thing missing: the silver tanks of compressed air, ubiquitous on any SCUBA trip. As the last student slides off the back of the boat and into the inky abyss, it becomes clear that this is no oversight, but just another day in the captivating world of recreational freediving.

Deep Thoughts

At first, everything about freediving seems counterintuitive: taking a deep breath and then disappearing, for minutes at a time, into the dark waters of the sea, away from the light, swimming into a world where our first primal instinct as humans—to breathe in oxygen—is impossible. For divers trained in SCUBA, maintaining a constant and abundant supply of air is priority No. 1. Why then do freedivers purposefully choose to descend to such depths with no oxygen at all, other than the few liters they can carry in their lungs?

“The big difference I see between SCUBA and freediving is how you are received in that underwater environment,” says Bill Van Deman, an avid spearfisherman for more than 15 years and owner of Tampa-based Abyss Freediving, which offers group courses as well as private instruction. “With SCUBA, the response you get from marine life is not completely natural. For photographers and hunters, if you go in as a breath-hold diver, everything in the environment sees you as another animal. You are able to get up close to fish, and large marine life will really perceive you as part of the environment.” He relates the comparison of  freediving to hiking through a national park, while SCUBA diving is more like driving through in an SUV.

Practiced in cultures around the world since ancient times, spearfishing brings many new divers to the sport, including Quirino. With more than a decade of experience spearfishing on frequent trips to the Caribbean with his buddies, he was interested in learning how to dive better and stay under for longer, while also picking up some safety tips along the way.

“We constantly go over to the Bahamas and dive, and you’re in the middle of the ocean with nobody around you for 50 miles,” he says. Because Quirino already had considerable experience on the water, the intermediate four-day freediver course—purchased by his wife as a Christmas gift—was a perfect fit.

Aside from spearfishing, many new freedivers find their way to this addictive sport through the gateway drug of SCUBA. This was the case for Ted Harty, a former SCUBA instructor who now teaches freediving and also trains instructors, through his Ft. Lauderdale-based company, Immersion Freediving. Harty is a well-known competitive diver as well, having broken national records in competitions held around the world. “When I switched to freediving from SCUBA, there was one particular reef down in the Keys that I had dived more than 500 times,” Harty says. “When I started freediving that same reef, I immediately noticed that fish reacted differently, because I was just a big fish. They are much more inquisitive and less likely to take off because you are absolutely a part of that environment as opposed to this crazy mechanical thing that’s down there.”

If these reasons are attractive to underwater enthusiasts, they can be positively game-changing for scientists and marine biologists. Ricardo Paris of Miami, and his wife Claire, a national freediving record holder herself, are currently in the process of creating a scientific freediving program at the University of Miami through his training company, Vortex Freediving. As an associate professor of ocean sciences, Claire has seen the benefits of safe and successful freediving within the scientific community.

“When you are dealing with shallower depths, it’s a much easier and less burdensome discipline than SCUBA,” Ricardo explains. “Our program adapts freediving techniques to certain fieldwork that needs to be done in science, like tagging sharks or studying the lifecycles of fish.”

Physiology Unplugged

At first glance, freediving seems deceptively simple; in fact, many snorkelers are in essence freediving when they take a deep breath and drop a few feet below the surface to get a closer look at the sea life below. However, the steps that properly trained freedivers take before, during and after their dives reveal a complex methodology designed to maximize air intake, minimize unnecessary movements that waste oxygen and, above all, prepare the body mentally and physically to deal with any safety hazards that could arise along the way.

Divers prepare for each descent by “breathing up” on the surface for several minutes. During our day-to-day lives, most of us use only a fraction of our lung capacity, taking shallow breaths that barely raise our chest with each inhale. Because freedivers will have just one breath for each underwater dive, they practice filling their lungs to capacity through a series of segmented inhalations, first filling their diaphragms as their stomachs extend, followed by their chests.

In freediving classes, students learn that just when you think you have taken the largest breath possible, there is still room for more. By lifting the shoulders, students are able to access the top-most portion of their lung capacity. Beginning and intermediate divers then descend to distances ranging from 10 to 40 meters, while advanced and competitive divers may go much deeper, continually equalizing their ears along the way and employing specific kick cycles to conserve energy, before returning to the surface a few minutes later.

If it sounds like a complicated thing to learn on your own, it is. But Floridians can catch classes from respected companies like Performance Freediving International (PFI) and get certified in proper techniques once or twice a month in cities around the state. PFI employs several full-time instructors while also partnering with local instruction companies, like those owned by Van Deman, Harty and Paris.

The techniques of the sport have wide-ranging applications, and PFI has developed courses to train everyone from a big-wave surfer eager to learn about breath holds in high-stress situations, to a magician who famously attempted underwater escape-artist tricks and world-record breath holds on national TV, to military teams including the U.S. Naval Special Warfare Group and U.S. Special Forces.

Crash Course

Depending on the level, recreational freediving courses typically span two to four days, often around a weekend, and include a mix of classroom, pool and open-water training. During these classes, new and intermediate divers learn about the physical side of the sport and what’s going on in their bodies as they make increasingly deeper dives.

The scientific phenomenon behind divers’ ability to hold their breath for long periods underwater is called the mammalian dive reflex (MDR) and refers to a series of physiological adaptations all mammals undergo when their faces come in contact with cool water.

First, the heart rate begins to slow, as much as 50 percent in humans, and even more in seals, otters, dolphins and other mammals that spend more time underwater. If you’ve ever splashed water on your face at the bathroom sink to calm down during a stressful moment, you’ve experienced MDR.

Next, the capillaries in the fingers and toes constrict, pushing more oxygenated blood to essential organs: the heart, brain and lungs. As the diver goes deeper, this blood shift increases. At more extreme depths, or after multiple dives, the spleen releases a fresh batch of red blood cells and pushes even more oxygen into the system. For all of these reasons, divers can achieve longer breath holds underwater than on land, and static apnea—the practice of holding one’s breath while lying face down in a pool—is an essential training technique.

Once students learn the science behind the sport, the idea of underwater breath holds becomes less frightening. Although new divers may find that perfecting their kick cycles or learning to properly equalize ear pressure can present a challenge, for many, the biggest hurdles are mental ones.

This was certainly true for Quirino. “The mental part was hardest for me—taking your mind somewhere else and off of having to breathe,” he says. “Sometimes my mind is too active; I can’t shut it off and go into a Zen or meditative state. You have to learn to do that to succeed in this class.”

Van Deman agrees, noting how this makes freediving different from many other athletic endeavors. “With other sports, people go into an accelerated mental phase: they become excited, they get pumped up,” he says. “With freediving, it’s the opposite. You want to approach it from a relaxed standpoint and take away the competitive mentality that we normally bring to sports.”

Danger Zone

Like any sport, freediving has its dangers. It’s been called the second most dangerous sport after BASE jumping. High-profile deaths, including that of Florida native Nick Mevoli at a 2013 competition, have cast a shadow over what, in many ways, can be a low-impact sport that is great for beginners.

The most common risk of recreational freediving is blacking out and losing control of your airway, which explains why dive students receive hours of instruction on safety protocol and are repeatedly reminded of the golden rule: to always dive with at least one other trained diver, and to take turns diving—“one up, one down”—so that the person going deep has someone watching him on the way back up, in case a loss of motor control or a blackout should occur. Ninety percent of blackouts happen at the surface, so instructors stress the importance of continuing to watch your buddy for a full 30 seconds after each dive.

“Freediving has a problem when it comes to perception,” Harty says. “The only thing the average person knows about freediving is something they’ve seen on the news about guys who tried to dive as deep as humanly possible and died. But competitive divers trying to break world records make up less than 1 percent of what freediving is. Most freedivers just want to play on a reef in 20 feet of water and like the idea that they don’t have to get a tank and wear all that gear.”

Harty also says that the low barriers to entry are part of what makes the sport attractive to all kinds of people—but conversely, much harder to regulate. “You can’t go SCUBA diving without taking a course, or get a tank refill without showing your certification,” he says. “But there is nobody who will stop you from freediving. That’s the risk—there isn’t a gatekeeper. Freediving is dangerous the way most people do it because they don’t know how to do it safely.”

If done properly and with training, freediving can be a low-impact sport that is relaxing, challenging, and ideal for students of all ages.

At Peace

“I have seen students from 11 to 72 years old have amazing performances,” says Van Deman. “It is a forgiving sport on the diver’s body, not something that creates a lot of shock, impact and stress on your joints and muscles.” In fact, for some divers, freediving has opened them to other healthy practices such as yoga, meditation and more nutritious eating, which helps keep the body in shape for deeper dives.

“You are exposing your body and your mind to certain extremes, so as a result, you become a lot more conscious about your health,” says Paris. “We started doing more yoga, pranayama breathing and meditation. All of that is key in freediving. It has pretty much been accepted by the whole freediving community that you need that flexibility, mental strength and breathing discipline from yoga.”

Back on the surface near Ft. Lauderdale, the divers climb aboard around 12:45 p.m., after a jam-packed morning of two sessions that began with some open-water training, followed by 10 dives, going as deep as 83 feet, or just over 25 meters. During their four hours on the water, the students swam past a number of blue runner fish, spotted a giant sailfish in the depths below and witnessed a rare surface appearance by a hammerhead shark.

After four days of classes, pool training and open-water dives, Quirino—who achieved personal bests for breath hold and depth during the course—is tired but all smiles. “I’m goal-oriented,” he says, “and have a great sense of accomplishment saying I have my certification in intermediate freediving.” But for Quirino, it’s more than just that.

“Whenever I go out fishing or out to the ocean, I call it church. That is my escape, where I am most happy. Getting the certification and being at my church, so to speak, I am extremely relaxed coming back on the boat and hearing the sounds of the waves. I’m always at peace being out in the ocean.”