My eyes are closed. I can feel my own heart slowly beating. Marie-Theresa Solomons gently touches her hand to my shoulder and I break surface. It's been two and a half minutes since I last breathed. Breath-hold diving, or apnea, is nothing new. All diving originates from it and although it's common for the Y2K diver to encumber himself with the modern trappings of multiple tanks, electronic computers, radiophones and new age rebreathers, some seek out a simpler more intimate way to dive. What is new is the growing interest in freediving. And the controversy. Critics unable to suspend their own belief as apneists suspend breathing for six or more minutes have concerns that participants may be damaging their brains. As an enthusiastic snorkeller of thirty years I was keen to discover more. Until recently little freediving tuition was available. Few scuba instructors had any personal interest in snorkelling or in teaching it. Indeed many perform badly if asked to try. For those who wanted to freedive it was pretty much teach yourself, as I did, and without guidance it was hard to progress. That has all changed now. The Solomons teach a range of freediving courses around the globe that culminate in students diving to depths in excess of 30 m. They themselves have both surpassed the 50 m mark, BSAC's recommended limit for air diving. The Solomons are qualified instructors for both "Pipin" Ferrera's IAFD organisation and for Umberto Pelizzari's Apnea Academy. There are obvious parallels to be seen here with the emergence of technical diving agencies such as IANTD and ANDI through which extreme diving became possible and eventually respectable. Over time it seems likely that freediving will also become mainstream and that the recreational diving agencies will eventually offer, promote and profit by it. The static apnea course I joined is entry level. Though static (motionless breath holding) is a discipline in competitive freediving and an end in itself, it's also the natural first stage towards prolonging breath hold times in open water. What is often forgotten in the clamour to criticize is that most breath hold divers are not pushing any limits, including their own. There is undoubtedly a macho element - those who will be hurt and will die as freedivers. Promoting apnea will inevitably encourage them to join. Casualties in diving, most of whom are self inflicted, are accepted in recreational and technical diving and both activities are heavily marketed. Freediving is on the same glidepath. However, the best defense is good training and an unshakeable disbelief in reincarnation. The Solomons provide the former. There is a tendency to shroud freediving in mysticism. Being at one with the ocean to me has usually meant I've ingested some. So I was sceptical of some of the content of the course and told the Solomons so. They accepted me onto the course anyway.

The course begins in the classroom with an orientation to the program. The Solomons co-teach, with Aharon tending to take the lead. Theory includes thorough explanations of how the human body learns to cope with prolonged breath holding. I hold mid-level instructor qualifications from PADI and BSAC and was surprised at the depth of information. Fortunately, the Solomons are plain speakers and start from what you do know then build your knowledge from there.

Next it is time for practical demonstrations of breathing techniques plagiarised from yoga. MT strips to her swimsuit and fully exhales, then sucks in her diaphragm. I can virtually see her spine through her navel. It's a remarkable demonstration of efficient breathing. Stripped to the waist, I try to do the same thing. The effect on my own midriff is like tossing stones into a pond. The Solomons both work on me until I've improved. The purpose is two fold: to maximise the gas exchange in the lower, and oft neglected, lobes of the lungs and to use the diaphragm as a piston to force highly oxygenated blood from the liver and spleen into the bloodstream.

Safety is stressed throughout - more so than on many entry level or even advanced scuba courses. It's a refreshing change to be apprised of the risks as well as the rewards. Aharon is candid in his discussions of fatalities that have occurred through failure to adhere to common sense and established safety rules.

The Solomons use a set of tables to increase breath-hold time through adaptation. Developed by scientists for legendary freediver Pellizari, the tables help the diver to tolerate lower levels of oxygen and greater levels of carbon dioxide in the body. I have no problem accepting the rationale - as a scuba diver we all go through adaptations as we submerge; as do other sportsmen such as climbers, aviators and athletes.

Other techniques are used. Removing the mask exposes sensors in the face to the cooler water and slows circulation. Keeping the chin on the chest avoids triggering baro receptors in the neck that stimulate breathing and reduce blood flow to parts of the brain and is why freedivers ascend without looking up.

Almost as a throwaway line Aharon lets us in on an intriguing snippet of information. It's been assumed that while humans can voluntarily choose to breath hold, the processes beyond this that affect oxygen distribution to the tissues are autogenic - in other words both involuntary and beyond our control. However freedivers appear to be overiding these processes and the Solomons are now the focus of a study by Dr. Paul Jabbot. He is interested in the evidence that implies that breath-hold divers' bodies have learned to shunt blood to priority areas as a response to apnea. The hope, and the far reaching implications, are that individuals at risk of some diseases, and existing patients, might learn to better prevent illness through developing similarly learned skills. For example, avoiding strokes by using techniques to lower blood pressure.

The pool sessions take place in virtual silence. The Solomons emphasise relaxation. I would breathe for a while, then drop my face into the heated water and close my eyes. My mind would clear completely. When MT touched my shoulder to bring me up I'd still have time in reserve. There was no rush to breathe, no tell tale muscle crawling around my chest... no desperation. Yet as a normal adult usually breathing 12-14 times a minute I'd skipped 35 breaths.

Throughout the pool sessions close supervision is maintained. Each of us has a partner topside who in addition to timing out surface and diving intervals ensures our safety. Physical contact is maintained at all times. The slightest change in the divers grasp of his buddy's ankles is meant to alert the buddy to a possible problem. On other courses I've seen full-blown blackouts. On the two courses run by the Solomons no one even came close.

So what do graduates of the Solomons' entry level course conclude? Mike Carlen, 32, is a professional documentary cameraman who holds a PADI Advanced Diver qualification. "I saw the Big Blue and was intrigued. I've enjoyed the course. It's very much an introduction to breath-hold techniques. I'd be keen to go on to the next stage. Tonight I didn't perform so well as yesterday. I had things to do with work on my mind."

Jenny Cooper is a PADI instructor who joined the course after trying breath-hold diving in a swimming pool. "It's pitched at a higher level than the average scuba course. To do this I think you need a basic knowledge of physiology, anatomy and it wouldn't hurt to have even more than a basic knowledge to appreciate what Aharon's saying." Asked if she would recommend the course, she said emphatically, "Oh, yeah. I think anyone who likes to try something different that is going to challenge their ability physically and mentally would enjoy it and they don't have to be a scuba diver to enjoy it."

Scott Bell, 28, and a scuba diver of five years who now works full-time in the diving industry is a graduate of the Solomons and a committed freediver. Attracted to freediving because he "didn't want to be encumbered by all the equipment on shallow dives," Bell also thought it might improve his air consumption on scuba, which it has. "Aharon and MT have shown me a freer, more serene aspect to the sport. They've also improved my knowledge of physiology. I like the way they stress safety first."

After the course I put some of the skills into practice in open water. 6m down and a full body length into a narrow tunnel the only noise was the low whine of my flashgun recharging. When it's batteries died I angrily flicked switches on and off and rattled it. A minute or so later I gave up, relaxed and lazily swam out. There was no noise. Just the sound of silence. And my brain? ...seemingly undamaged after all.