Yesterday had not gone well. In fact, it went badly. Temporarily blinded by a powerful video light, Brett LeMaster collided with a safety diver. As a result, his cardio rhythms increased from their extremely relaxed rate of 30 heartbeats per minute, robbing what little stored energy remained in his body. Making matters worse, strong currents during his ascent added more time and work to the dive, triggering a shallow-water blackout just below the surface. A situation like this during a world record breath-hold diving attempt to 266 feet is like getting thrown from a very big horse. Undaunted, like a true competitive athlete, LeMaster was back off the coast of Grand Cayman's Seven Mile Beach ready to try again the following morning. Constant Ballast diving such as this is regarded as the purest form of apnea diving. The rules dictate that a diver must complete both the descent and ascents under his or her own power, with the same weight he or she left with from the surface. An hour before the dive, LeMaster begins a series of focused relaxation and breathing exercises. He uses a combination of deep diaphragmatic (stomach) breathing in conjunction with extensions of the inter-costal (chest) muscles stretching outward. This deep breathing method draws air deep into the lower portion of the lungs, the region where the majority of oxygen transfer actually takes place. Moving into the water, he immerses his face - sans mask - and breathes from a snorkel for five minutes. Facial immersion triggers a slowing of his heart and metabolic process. Next, he exhales fully and performs a negative pressure dive. That's a dive to 30 feet with the lungs completely empty. This simulates the effects of being at a depth of 100 feet with lungs full. Three additional dives are then made with lungs fully inflated, each progressively deeper, with the last to 120 feet. His in-water acclimatization exercises have transformed Brett's land-based being to a creature more akin to the sea. This is just one of many transformations for the 36-year-old from land-locked Albuquerque, New Mexico. His trek to the water began with his scuba certification in 1988. The next year he obtained a PADI scuba instructor certification. He worked in the Bahamas and Cayman Brac for the next eight years, developing a passion for the free diving that is now his life. "I first started doing it when I was with Blackbeard's Cruises, mainly to help get fish and lobster for our passengers' dinner table. I found it enjoyable because you can get a lot closer to fish than you could on scuba. Later, when I landed here and began looking down the edge of the wall at the way it would drop off from a depth of 50 - 60 feet on the south side of the Brac to, well, the bottom of the Cayman Trench, it was just too much. After that, I decided that I wanted to do something beyond what I had been doing before." Finding the Dolphin Within Among veteran free divers, there is a belief that life not only emerged from the oceans, but that some part of us remains a creature of the sea. "There is a dolphin dormant in all of us," says Jacques Mayol, a pioneer of modern free diving. Proof of our kinship with dolphins, he asserts, is the mammalian diving reflex. Research from the 1800s showed a reduced heartbeat (bradycardia) in ducks immersed in water. Studies in the 1970s and '80s showed the North Atlantic Weddell seal can reduce its heart rate from 120 bpm to an astonishing 10 bpm. This lowers the metabolic rate and conserves the body's energy and oxygen stores. Surprisingly, this natural adaptation is quite genuine in humans, too. When the human head is immersed in water, nerves in the lips will trigger the heart rate to drop by 5 to 15 percent. It's this mechanism that has contributed to the survival of people who have been accidentally submerged in ice water for up to 40 minutes. According to well-known free-diving instructor Kirk Krack, when bradycardia kicks in, the diver will experience his greatest drop in heart rate -- as much as 30-40 percent -- between depths of 30 to 60 feet. This is especially true after kicking ceases and the body further relaxes. Developing and harnessing our latent aquatic biorhythms is as much a psychological process as a physiological one. Free-diving masters know that focusing thoughts and relaxing is as important as repeated exposure to the marine environment. During descent, LeMaster performs a mental exercise he refers to as a "body check" to identify and rid his body of any tensions. "When you're working to activate your diving reflex, you don't want your muscles to feel tense," he says. LeMaster also suggests taking in the environment. "Feel the ocean as much as you can, the movement and soft, smooth feel of the salt water on your skin. Listen to the sounds of the reef." With the sound of loud, annoying regulator exhaust bubbles removed, he says, the ambient noise on a reef from lobsters grinding their mandibles, shrimp snapping their claws or parrotfish nibbling on coral become quite discernible. "These are the kind of things I focus on." Pushing the Limits After an hour of preparation, LeMaster is seated on the swim platform. He has slowed his heart rate to 50 beats per minute. Instead of the more familiar sun-lit shallows of the reef, the world below is an infinite expanse of deep blue. Surprisingly, late November provided an invitingly calm sea with lukewarm temperatures. The countdown for the dive begins. Sliding silently into the water, LeMaster arches to commence the dive. Propelled by long bladed fins, he plunges rapidly, 30, 60, 100 feet with slow, fluid sweeps. Reaching a depth equivalent of four atmospheres, Brett's vital lung capacity is compressed to a fourth of its original size. This is equal to the air normally remaining in your lungs after a forceful exhalation. World champion free diver Tanya Streeter has described the sensation at this point as a tight, uncomfortable feeling in the chest and wall of the throat. "It's the part of the dive that, if I am going to bail, here is where it's going to happen. Once you get through it, it doesn't get worse, it will even let up." Minus a mask, LeMaster's only reference point is a single line weighted with 150 pounds of lead 44 fathoms below. In a near deep meditative state, the only sound Brett acknowledges is the tapping of tanks by safety divers communicating his progress. Descending deeper, he triggers additional physiological adaptations. His heart rate drops to 30 beats a minute. Arriving at 266 feet, LeMaster's lung volume has compressed to a ninth of its original size. All the while, his ears and sinus cavities, drawing air from his lungs to equalize, have increased their own volume nine times! Breath holding and increasing hydrostatic pressure causes LeMaster's thoracic cavity to fill with a pint or more of plasma to compensate for the lungs' diminished state. Meanwhile, other vessels shut down to restrict blood flow to his arms and legs, keeping oxygenated blood around his heart, liver and brain. Plucking the tag that will verify his depth, LeMaster still faces the most difficult and dangerous part of the dive -- the ascent. The Ever-Mounting Oh-God! Factor As a breath-hold diver's body uses oxygen, carbon dioxide accumulates in the blood, triggering a physical and psychological need to breathe. Ignoring the body's request for breath triggers involuntary contractions. For deep divers like LeMaster, these contractions may begin halfway through the ascent. At the same time, perception plays a dirty trick on the mind, casting the appearance of the surface a long way off. Even when it's less than 50 feet away, the mental response is "Oh God, I'm not going to make it!" "When the first contraction hits, you have to stay focused, telling yourself you have time. You have to stay relaxed, instead of picking up the pace, which will deplete your oxygen reserves even faster," says LeMaster. Near the end of his dive, the carbon dioxide in LeMaster's body is so high that he experiences a constant stream of riveting, near-debilitating contractions. "At this point, most divers would give up," he says. "It takes a lot of practice and training to maintain your focus and continue the ascent." Among new free divers, tolerance to carbon dioxide buildup and the accompanying spasms is usually low. Divers like Mayol, LeMaster and Streeter expand their control over this mechanism by anaerobic endurance training and mental conditioning. In his book, Homo Delphinus, Jacques Mayol asserts, "The first error to avoid in breath holding is fighting against the seconds. To hold the breath effectively, even though it seems paradoxical, it's best not to think about holding. To immerse oneself in the flow of things, letting oneself be transported to a state of complete calm and tranquility." Half the battle, veterans say, is learning to overcome anxiety by remaining calm. "What you end up discovering when that first breath contraction hits is that you don't necessarily need to be at the surface right now," claims Krack. Recognizing the start of the contractions actually reduces the sensation and its discomfort. During competitions it is not unusual for divers to experience as many as 30 contractions per dive. "It's all a matter of understanding that you can persevere," says Krack. There is a fine line between suppressing the psychological need and the actual physical requirement for air. Cross this line and the body simply ceases to function. The result is a shallow-water blackout, the ugly reality of breath-hold diving. Blackouts are triggered by the re-expansion of oxygen-poor air that occurs as the diver approaches the surface. At this point, vital reserves of oxygen stored in the body's surrounding tissues - including portions of the central nervous system - are drawn into the lungs. The result is a temporary loss of consciousness. Temporary, so long as the diver can be brought to the surface and revived. The backstop of safety divers and on-site medical personnel helps mitigate the danger of shallow-water blackout during record attempts such as LeMaster's, but the danger remains very real. For recreational free divers, the best safeguard against blackout is an awareness of personal limits. The best safety response is a buddy system that leaves one partner on the surface while the other is immersed. Lure of the Deep There has been a renewed fascination in free diving in the past few years, not only in competitive events and underwater hunting, but also among mainstream divers who have no desire to push the limits. Indeed, the vast majority of the world's apnea divers work at depths between 20 and 120 feet, dropping comfortably down for periods lasting two to three minutes for hours on end. Some consider free diving to be a graceful, relaxing, and even poetic means to eco-bond with mother ocean without being a slave to equipment, while others view it in a deeper spiritual fashion. Streeter believes her vocation is "more than just going down to look around. Free diving, she feels, is also a means to look within. "Certainly, the desire to test ourselves through our abilities and redefine our limits is one thing, but the reason we become free divers is because of our sense of belonging in the ocean, feeling blessed with our comfort level in that environment, diving like other animals," she says. "We're not freaks of nature, no gills behind the ears, just a group of people who harbor that kind of passion in free diving." LeMaster affirms this belief. "Although not everybody will be able to set records, we all have enough of a diving reflex built in to achieve pretty respectable depths and/or times," he says. "All it takes is desire and enough practice to develop a comfort level in the ocean." Both Brett and Tanya feel that anyone interested in free diving should treat it like scuba diving. "It's more than just grabbing mask, fins and snorkel and jumping in the water," Streeter warns. "The mechanics of breath-hold diving must be understood, as well as the physiological aspects of the body at depth. Also critical is proper conditioning and training to avoid getting hurt. In free diving, knowledge is definitely an asset, and ignorance is not bliss." From start to end, Brett LeMaster's world record dive took 2 minutes, 50 seconds to complete. In doing so, he bested Umberto Pelizzari's 263-foot record in constant ballast, attained in October of 1999. "It's a really neat feeling when you reach a point when you have gone deeper than you ever thought possible, surpassing even those and#91;depthsand#93; attained by people I still idolize," LeMaster said proudly. "It's the extreme edge of the sport where you go when you really want to challenge yourself."