Blood volume and body mass.

My research has led me to believe that when training muscles for freediving, you can take two different paths. Even marine mammals take one or the other.

- The first method is to develop almost entirely fast twitch muscles. This results in a huge supply of ATP and creatine, which generate energy without oxygen. This is the path taken by some seals who have over 70% fast twitch muscle fibers.

- The second method is to develop high myoglobin content in slow twitch muscles. This is the method taken by the extreme deep divers (elephant seals, most whales). This results in a huge oxygen storage in the muscle, but the muscle is not very strong, because as much as 30% of the muscle is composed of myoglobin bound in the slow twitch fibers. Such animals often have 90% slow twitch fibers, and often the O2 storage capacity of the muscle myoglobin is more than that of the entire lungs & blood.

Now, although the second method may lead to the greatest dives, it takes far longer than the first. But that's not all; no one really knows how to accomplish the second method. Myoglobin muscle biopsies are virtually impossible to get.

The first method (fast twitch) is well established. The method to build such muscle is extremely well researched. Various training programs such as Colgan's power program are readily available in print to accomplish it. I can say from experience that it works.

The second method is so mysterious and undeveloped that it takes guts to even spend time trying it. All the animals which have developed huge myoglobin exhale before they dive. So, the only thing we can infer is that practicing exhale dives may eventually lead to high myoglobin. It is quite certain that the muscles must be exercised in a deoxygenated state in order to build myoglobin, but that alone is not enough, because most athletes doing anaerobic training do deoxygenated their muscles (altitude training in particular), yet neither of these methods develops much myoglobin. Some studies have implied that exercising the muscle when the muscle is not receiving blood supply is the key to myoglobin growth. Thus, exercising the muscle in an extreme blood shifted state may be the key. During exhale dives, the blood shift is extreme. This also implies that no exercise on land could produce high myoglobin -- except, of course, if you tie a blood pressure 'cuff' around your upper thigh (which I have tried), but this method is very dangerous since you can burst blood vessels.

Emperor Penguins are born with low myoglobin content in their muscles. Their muscle myoglobin triples or quadruples in their first two years of life, as they dive continuously.

To finish, I'd say that the worst muscle for freediving is comprised of entirely slow twitch fibers, with low myoglobin content. These fibers consume huge amounts of oxygen. Exercising in the presence of oxygen (i.e. steady state cardio), produces such muscles, and it also increases the capillary density, providing more blood flow to the muscles. In seals, there is almost no capillary network to supply blood to the muscles. Blood is better used to supply the brain; the blood shift in these animals is so strong that during a dive there is almost no blood pumped to the muscles, so why bother with diverse capillary networks to deliver oxygenated blood? Let the muscle survive on its own stored energy, in creatine, ATP or myoglobin.

Yet, certain 'cardio' athletes such as Topi Lintukangas may appear to have great freediving performance. I think this is because their muscles have become very efficient in general. This does not mean that their muscle type(s) are ideal for freediving. The same athletes, spending their time producing freediving specific muscles, could probably dive twice as deep.


Eric Fattah
BC, Canada

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