What is Freediving?
Freediving is the sport of breath-hold diving that involves diving under water for depth, distance or other goal or activity such as spearfishing, on just one breath of air. There are disciplines such as constant weight apnea (CWT) and constant weight apnea without fins (CNF) where the diver descends to a depth following a guide line they must not use for assistance and returns to the surface without dropping any weights. There is also free immersion apnea (FIM) in which the diver descends using the guide line for assistance but without the use of fins or ballast.
Breath Training
I have long been interested in training my breathing competency, capacity, altitude adaptation and breath-holding ability. I have experimented with breathing techniques, breath training devices used in physiotherapy and some forays into underwater swimming and rock carrying. From a training perspective there are 3 main ways to obtain respiratory related adaptations: Restricted breathing, resisted breathing and hypoxia. Restricted breathing is the equivalent to breathing through a straw, the air flow is reduced and it takes longer to inhale or exhale fully. There are benefits to exhaling this way, such as the pursed-lip breathing recommended to physiotherapy patients with lung disease, for expanding the lungs, controlling the breath and inducing a relaxation response. However, true resisted breathing to train the inspiratory and expiratory muscles, weight-training for the diaphragm, is what one would experience with threshold devices such as the Power Lung. In this case, no air can be inhaled or exhaled through the mouthpiece until the required force, or threshold, is generated by the inspiratory or expiratory muscles, at which point there is a free flow of air, providing the force is maintained above the threshold. Hypoxic breathing is what one would experience at altitude where the air is thinner, or atmospheric pressure is less, than at sea level. Hypoxic training can lead to biochemical adaptations such as increased levels of EPO that increases red blood cell production, and up regulation of 2,3-diphosphoglycerate that leads to oxygen binding less aggressively to haemoglobin and therefore being more easily delivered to the tissues of the body. Many devices on the market that restrict breathing claim to deliver the benefits of hypoxic training, whereas the reality is the user is still breathing air with the same concentration, but they are having to work harder for it. The masks also build up some CO2 in the dead space of the mask, so although surely intensifying a training session, it is not the same as breathing air at altitude.
My Experience with Freediving
I started structured freediving training in March this year with Auckland Freediving Club (AFC). During daylight savings hours there are training sessions in Lake Pupuke and more things going on in the ocean. As I started right at the end of summer I decided to throw myself into the pool training and breath holding side of it first, so that by the time I came to do any depth dives, I’d be at least somewhat familiar with the sport. My first mistake was thinking that you couldn't get cold in an indoor pool, but I quickly found out that you can when you're doing static breath holds. So after my first week, I went out and bought a 5mm wetsuit which is minimal requirement really for statics and probably a bit thick for dynamic stuff.
I was approached in May about competing in the T3C competition in August and jumped at the chance to have something to aim for. There are 3 disciplines at a pool competition: Dynamic apnea with fins (DYN) and dynamic apnea without fins (DNF) where the goal of the dive is distance, and static apnea (STA) where the diver holds their breath as long as possible while motionless face down in the water. The training at AFC covers all of these areas during a normal training month but I thought the best way I could prepare for the competition would be to increase my breath hold as much as possible in the short time available. I found a four week training plan designed to take someone with a 2 min breath hold to a 5 min breath hold in just 4 weeks. In addition to what I was doing in the pool with AFC and by myself on dry land, I added in the apnea training from this program. A big part of this is completing sets of what are called O2 tables and CO2 tables both in the water and on dry land.
BEWARE! It is crucial to always have a buddy when doing this kind of training in water as there is a phenomenon called shallow water blackout. This is a loss of consciousness due to cerebral hypoxia that can happen toward the end of a breath hold dive, even if the diver does not feel an urgent need to breathe.
O2 and CO2 Tables.
CO2 tables typically involve sets of a fixed breath hold time, of around 50% of your max breath hold time, with decreasing rest intervals between each starting with around 2 minutes and working down to 30 or 15 seconds. They are designed to increase your tolerance to elevated levels of CO2 in the blood.
O2 tables are based on several apnea sets, or breath holds, of increasing duration with a fixed rest interval between each. Typically you will start at around 40% of your max breath hold time and build up to about 80%, or closer to 100%, in 15 or 30 second increments, with a fixed rest time of around 2-3 minutes between each. O2 tables are designed to allow your body to learn to operate under low O2 conditions and increase your maximum breath hold time.
First I completed 2 weeks of daily CO2 tables, usually with 7 or 8 sets of breath holding. I came to quite enjoy these sets and I was surprised to find they were becoming easier towards the end of the routine, as the rest time was decreasing. But I still didn't have any idea if I had increased my breath hold, as the apnea times were fixed to 2 minutes or under.
I then did 2 weeks of O2 tables where I was pushing my breath holding limits and trying to achieve a 5 minute dry STA by the end of it. I did not follow the program to the letter as I was mainly doing the tables dry as I did not have access to a pool or dive buddy every day of the week. I also did not stick to the physical training part and instead continued my normal training routine, somewhat modified to include more aerobic work. I was amazed by the fact that my best breath hold times were coming on the last round of the tables after multiple apnea sets with only short breathing times in between. By the end of the first week I managed a 3:30 hold and then at the end of the second week a 4:30 hold with the 5 min mark still elusive.
Competition
When it came to the static day in the pool, I knew most of my preparation had been about that and, if I could improve my breath tolerance to high levels of co2 and low levels of o2, that the other disciplines would benefit too. I had adopted the practice of counting my diaphragm contractions in 10s while holding my breath to have a focus and I knew from my dry attempts that I could take 60 contractions but hadn't really been beyond that. In training on the Monday before the competition I was cold and shivering during the static sets but even so, managed a 3 minute and a 3:30 hold.
STA
On the day of the competition the contractions were coming on quickly, despite the fact that I was warming up with several rounds of shorter holds. When it was my turn in the competitors zone, I put my head under the water and was surprised to hear something I hadn't heard before doing a STA. The sound of my own heart pounding way too quickly and deeply in my chest. I put this down to nerves and tried to focus on relaxing and lowering my heart rate. This quickly came down and faded into the background while I listened to my coach and tried to relax every last muscle and let all thoughts leave my head.
The contractions came on earlier than I would have liked so I dutifully started counting. 10, 20, 30, over 2 minutes and feeling good. 40, 50 starting to struggle, I was close at the 3 min mark, the minimum I wanted to achieve. 3:30 passed and i was happy, feeling like i could get to 4 min but I had reached 60 contractions and, even with my eyes closed, I could tell things were starting to get a little weird, so I pulled out and got a 3:38 time and white card. This was a PR for me in the water, although I had achieved more dry. In theory the MDR should allow you to get more in the water but everything else needs to be right, like environment, state of relaxation, body temperature…
DYN and DNF
The following day at the DNF in the 25m pool, I was feeling happy with my technique and aimed to complete at least 2 lengths. I went through the whole preparation, about a 45 minute routine of stretching, dry breath holding, getting wetsuited up and completing some practice dives. All that just for a dive that lasts close to a minute. It certainly helps though to be able to reach the right state of mind for the dive ahead. In fact, I’ve never been involved in a competition environment before that’s so chilled out, with each diver completing their own routine with a meditative-like focus. So when it came to my DNF I was calm enough to try to get close to my best attempt, but still struggled to get 2 turns in. I came up soon after the second push-off and achieved a score of 54m.
The following morning the DYN discipline was held in the 50m pool. I had only trained once in the 50m pool and I was apprehensive to complete at least one full length and start making my way back. All the prep went well and I felt comfortable in the water with a borrowed pair of long freediving fins to help propel me. My only worry was coming up close to the middle of the lane rope, where it would be at its slackest and having to hold my airway above the water to get a white card. However, the dive went well, I made a clean turn, and surfaced right after the middle of the pool. After kicking to hold myself up for 30 seconds, I was awarded a white card for a distance of 76m.
Summary
In terms of performance gains from this experience, I made some initial gains mainly through improving my finning technique and streamlining through the water. I put this down to the host of neural adaptations and that any beginner goes through when introduced to a new sport. Although I can see that from here out, there are micro gains to be had in terms of correct weighting, gear such as wetsuit, mask and fins, and refined technique, it is obvious that from the breathing and apnea perspective, this is something that must be trained regularly to make improvements. In comparison to my raw potential when I first tried the sport, I haven't made any enormous leaps in performance or distance even with all the training. However, the health benefits of slowing down and focusing on the breath are well known and the freedom this training can afford us to experience the underwater environment is unparalleled.
