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Freediving - aerobic or anaerobic?

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Phat not fat!
Feb 12, 2002
OK a question. It has been confusing me for a little while and I might well have to do a presentation on this.

Is freediving an aerobic or anaeribic sport? Or both?

The more aerobically fit you are the more efficiently you use oxygen. Therefore, theoretically, the fitter person should be able to last longer on 1 breath, right?

However the nature of the sport is with out oxygen (anaerobic). This type of exercise is, however, usually defined as a short, powerful movement like a jump or a sprint. Now correct me if I’m wrong but freediving is a slow relaxed movement, and you are not totally without oxygen until the very end.

So is it that the sport is a mixture? The build up is very much aerobic (breathing exercises etc) but the event is actually both. Working as efficiently as possible on one breath until all the oxygen is used at which point is becomes anaerobic?? But at this point are you still moving in a relaxed state or are you sprinting for the surface?

Or is it a case that exercise when in apnea falls into a completely different category?

Oh my god, I’ve gone cross eyed!!!

Thank you from a very confused Porky

A breath-hold dive starts out anaerobic for the first 15 or so seconds, then the aerobic system starts to kick in; then, it becomes anaerobic again. The point at which it becomes anaerobic is not necessarily when you run out of O2 near the end; it can become anaerobic at great depth due to lack of blood flow to the legs, even though there is tons of O2. Remember, aerobic/anaerobic refers to a single muscle, not the whole body; part of the body can be working aerobically and another part anaerobically.

Even for one muscle, that muscle is usually both aerobic and anaerobic, but the emphasis shifts from one to the other.

Eric Fattah
BC, Canada

Hi Porky,

I agree with you and think that at the start of the dive it’s more aerobic and as the heart slows down, and less oxygen is available your muscles start working more in an anaerobic state.

Someone who knows more about sports science could probably answer this better, but I suspect you always use both no matter what you do. For example riding a bike is aerobic, but say you go up a hill or sprint, you start building up lactic acid, ie anaerobic process. It’s sort of like a short term reserve. So when your muscles are working harder then the aerobic process can handle using the available oxygen, it start dipping into the ‘reserve’. Although under heavy loads, ie weight lifting, using stiff fins etc you build up lactic acid much quicker, and the muscles probably don’t go into the aerobic state as much.

For me I notice this lactic acid much more towards the end of a dive, specially a deep dive, or using stiffer fins. For performance dives I guess it’s an advantage to train to be able to use stiffer fins, so that your leg muscles start working in more of anaerobic process and therefore use less oxygen.

Be Careful

Remember that just because something is anaerobic, it doesn't necessarily produce lactic acid. There are several anaerobic pathways, but only 'anaerobic glycolysis' produces lactic acid. The other anaerobic pathways are 'alactic', and produce basically free energy with no byproducts, but they are small reserves.

So, feeling the presence of lactic acid means that you're using 'anaerobic glycolysis', but feeling no lactic acid (i.e. in the very start of the dive), doesn't tell you which pathways you are using.

Eric Fattah
BC, Canada
A question...


Seems like you guys know allot about those things, and maybe you have an answer for my question. When I do dynamic I get allot of lactic acid in my legs around 75 meters. What can I do to prevent this? Any way of training? How?


Hi Rumblefish.

Training should encompass a good spread of aerobic and anaerobic exercise.
Any exercise becomes aerobic when a certain percentage of your maximum heartrate ( age dependant ) is achieved and maintained for at leat a prescribed period. ( exercise type dependant ) This type of exercise ie typically aerobics, running, swimming, etc will build endurance and stamina generally referred to as fitness. Endurance and stamina and a efficient cardio vascular and respiratory system are must haves for a good freediving performance.

Heavy weight lifting will increase muscular skeletal strength and resilience. This type of exercise typically occurs in conditions of lower respiration and heartrate ie anaerobic. A good strong kick will result from this.

Freediving occurs in conditions of low heartrate and low respiration. anaerobic. It is erroneous to say that because you are breathing purposefully before you dive and that in the first part of the dive you are oxygenated , therefore the first part of the dive must be aerobic. Like wise to say that the latter part of a dive is anaerobic because you are running out of air.

Lactic acid is formed by the burning of glucose and oxygen with lactic acis and Co2 loosely as by products. The effects of lactic acid is usually felt the day after extraordinary exercise as stiffness. Soreness would be as a result of the destruction of muscle tissue due to extraordinary work. This destruction is desired by body builders as the repair by the body intelligently overcompensates incase this type of work is to be done again resulting in a stronger bigger muscle.

The fatigue you feel at the end of a dive is as a result of the legs just having no more fuel to burn ie glucose, or no more fire to burn it with, Oxygen. Lactic acid, the undesired by - product of chemosynthesis has a part in this especially causing that impending cramp feeling. Co2 also need to be whisked away efficiently by the blood stream. An efficient cardio vascular system and strong muscular skeletal system will use oxygen more efficiently, utilising less to do the same work, producing less by product, limiting fatigue and lactic acid buildup.
I would say training should include at least heavy weight for legs, circuit training, and swimming like hell consistently. ( I hate running ) Im a fish not a rabbit.

convincing ? sounds good :)


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Re: anaerobic

Originally posted by Skindiver
Hi Rumblefish.

Freediving occurs in conditions of low heartrate and low respiration. anaerobic.


Some good points skindiver. But I don't agree with your definition of anaerobic exercise. Even if you have low respiration you are still supplying the body with oxygen. Anaerobic by definition means 'without oxygen' therefore low respiration = with oxygen = aerobic.

The question I posted was with reference to the fact that as a freediver you try and overcompensate the amount of oxygen in the body (hyperventilation and packing to achieve this). Therefore as you are enabling your muscles to access an increased supply of oxygen enabling an energy breakdown via the aerobic system. Therefore some of the activity has to be aerobic even if it is only for a short while. Admittedly, the % energy from anaerobic pathways is probably a lot greater, but it would be naïve to say it was 100% anaerobic.

What was causing the confusion was that if you look at typically anaerobic sports (ie, sprinting, long jump, high jump etc) the movement is very explosive and lasts a relatively short period of time. In contrast, typically the pace in aerobic sports (ie. Long distance running, walking etc) is a lot slower mainly due to that duration of the exercise and the need to conserve energy (you wouldn’t see a marathon runner sprinting a marathon).

Now, when finning it is slow and relaxed to conserve oxygen - very similar to typical aerobic sports. To look at it in no way represents an anaerobic sport – it is not explosive. But logically you would say it is anaerobic because you are holding your breath!

I think the brain pain is coming back!!!
Still as confused as ever

If freediving were purely anaerobic, you would not consume any oxygen, and thus you could never black out.

If freediving were purely aerobic, your legs would never get tired; tired legs can only occur once the stored ATP and creatine phosphate have been depleted. If they are depleted, then it proves you were exercising anaerobically for at least a short time.

So, by this simple analysis, freediving must be both aerobic and anaerobic; end of argument!

Eric Fattah
BC, Canada
training balance


Since freediving is both aerobic and anaerobic, how do you divide up your training regime? How much time do you spend on aerobic exercise versus anerobic exercise? How much time do you spend weight lifting under both of these conditions.
The idea that it invovles both processes makes sense. How much time you should devote to each one still seems open ended to me.
To be or not to be

I've been out of the forums for a while because of work.

This discussion is very funny.
Aerobic means "with oxygen"
Anaerobic means "No oxygen"

If we take it literally is imposible to be "anaerobic" unless your death.
Anaerobic or Aerobic means the pathway your body uses to get energy for work. The sports with a high respiratory rate (minute ventilation) are know as aerobic, like running, swimming, cycling, etc. But even those sports has an anaerobic phase that limits the exercise, it's the anaerobic threshold or the point that the CO2 production is over the Oxygen consumption, your body is starved from Oxygen due to the high metabolic demands and start the anaerobic metabolism that finnally limits the exercise. The aerobic exercise improves the ventilation and the oxygen use by the mithocondria, and finnally improves or delay the anaerobic threshold.

Anaerobic exercise are those, in wich you don't use your ventilation to couple the CO2 production as weight lifting, that doesn't mean that your body is "anaerobic", It just mean that you are not using your respiratory system to eliminate CO2, it causes vasodilation and afeccts the blood flow. In "anaerobic" exercise the anaerobic threshold is lower than in aerobic exercise.
It's just a word's game, but the Freediving is an "anaerobic exercise".

I had a strange feeling in dynamic pool training.
After about 70 m had a heavy feeling in my legs, but the burning came only when swimming the 5 m that rested to the end of the pool. I had rested for about 5 sec. and i did some breathing.

Why does the burning come after i restarted breathing????


Freediving is not an anaerobic exercise. Freedivers DO USE their respiratory system to eliminate CO2, even though they are not breathing. The CO2 moves from the blood to the lungs, eliminating most of it from the blood.

Read any research paper and you will see that seals dive 'aerobically', except during long deep dives. The research papers define the 'aerobic dive limit' as the maximum depth an animal can dive to, without accumulating anaerobic waste products (lactic acid etc.) Dives beyond the aerobic limit cause waste product accumulation.

Eric Fattah
BC, Canada
Hi all,

I think part of the confusion is that the terms aerobic & anaerobic EXERCISE or SPORTS is a really simplification. Just a way to categorize. You have to think more about what the body is doing in terms of individual muscles. If you look at Eric's comments earlier :-

"Remember, aerobic/anaerobic refers to a single muscle, not the whole body; part of the body can be working aerobically and another part anaerobically. "

Imagine riding an exercise bike, aerobic ?
Now while on the bike start doing barbell curls, aren't the arm muscles working anaerobically ?

This too is a simplification, as Eric pointed out the muscles will utilize both aerobic and anaerobic processes with different % of each.

Now throw in the respiratory system, the heart, bodies reaction to low O2, depth, water temp......
It's not that simple is it ?!

Eric, thanks for your comments, it makes a bit more sense to me now.
Nice one guys. Some really good points in here. Clears things up quite a bit. Don't feel too confused now. The concept of breath hold exercise being partially aerobis was confusing me loads!!!

I realise now that by looking at it a bit differently it makes a bit more sence! Chees for your input.

a slightly less confused Porky:D
The anaerobic process , also known as glycolysis, is usually the first to kick in. Cells break down specific carbohydrates (glucose or glycogen in muscle) to release the energy for resynthesizing ATP. Unfortunately for the athlete, the anaerobic metabolism of carbohydrates can yield a buildup of lactic acid, which accumulates in the muscles within two minutes. Lactic acid and associated hydrogen ions cause burning muscle pain. But lactic acid and its metabolite, lactate, which accumulates in muscle, do not always degrade performance. Through training, the muscles of elite competitors adapt so that they can tolerate the elevated levels of lactate produced during high-intensity exercise.

Even so, lactic acid and lactate eventually inhibit muscles from contracting. So anaerobic glycolysis can be relied on only for short bursts of exercise. It cannot supply the ATP needed for the sustained activity in endurance events. That task falls to aerobic metabolism-the breakdown of carbohydrate, fat and protein in the presence of oxygen. In contrast with anaerobic glycolysis, the aerobic system cannot be switched on quickly. At least one to two minutes of hard exercise must pass until the increase in breathing and heart rate ensures delivery of oxygen to a muscle cell. During that interval, the athlete depends on a combination of stored ATP, the phosphocreatine system or anaerobic glycolysis to provide energy. With the activation of the aerobic processes, these other systems function at a lower level. In the aerobic phase, for instance, lactic acid and lactate are still produced, but they are consumed by less active muscles or metabolized in the liver and so do not accumulate.

Although the aerobic system is highly efficient, its ability to supply the muscles with energy reaches an upper threshold. If still more ATP is needed, the muscles must step up the use of various other energy sources. A soccer player in the middle of a 45-minute half, for example, would depend mostly on aerobic metabolism. But if he needed to sprint briefly at full speed, his body would immediately call on stored ATP or ATP reconstituted by the phosphocreatine system to supplement the aerobic system. Similarly, if this high-intensity sprint continued for five to 15 seconds, the player would experience a rapid increase in the rate of anaerobic glycolysis. As the play ended, the body would return to its reliance on the aerobic metabolic system, while the capacities of the other energy systems regenerated themselves.

According to this definition it appears that the freediver would likely dive aerobically for the first moments of a dive but only as a result of the momentum of the interrupted natural aerobic process by from which we produce our daily resting energy for maintainance of body systems . The requirements of commencing kicking and especially the return to the surface would most likely switch on the anaerobic process by design, giving a high burst of energy not necessarily created by diminishing O2 levels.
Whilst aerobic and anaerobic systems are used in a dive, ( as in all exercise to varying degrees ) the nature of the exercise is by definition anaerobic due to the contrived low respiration( nil ) and heartrate ( low) being insufficient to drive the aerobic system continiously.
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Good post skindiver, very informative! Answering the question very well i feel. Nice one!

A, free from confusion, Porky:D (for now!!!!!)
Re: anaerobic

Originally posted by Skindiver

I would say training should include at least heavy weight for legs, circuit training, and swimming like hell consistently. ( I hate running ) Im a fish not a rabbit.

convincing ? sounds good :)



Thanks for the info skindiver, at the moment I'm doing Ashtanga Yoga, Spinning and swimming ( with monofin ), and now after reading what you wrote I will probably play around with some heavy weights as well. But I don't know what circuit training is ( english isnt my first language ), could you please give an example?

Thanks for all the info, Mathias
a bit of a twist...

there's another factor to consider here, guys.....

your skeletal muscles are composed of 3 different types of fibers:
type I
type IIa
type IIb
the contraction period for these are slow, fast, very fast, respectively.

type I has a higher resistance to fatigue than the type II's, where typeIIb has the lowest resistance of all.

type I has a high oxidative capacity and a low glycolytic capacity. it also uses triglycerides for its major storage fuel as opposed to glycogen for the typeII's.

everyone has all of these types of fibers in their body(all in different proportions). it's your brain and spinal cord that determines which fibers get fired, according to the movement need. each type has its own motor unit. one motor unit will not have the ability to fire more than one fiber type.

the type I's are more generally used for aerobic purposes in smoother, slower, controlled movements. it's possible to gradually transform fiber types by certain excercises. what i'm getting at here is that the faster twitching fibers(type II) will fatigue faster and more readily produce lactate. as we've heard, this isn't so good when diving. so,... why would one want to have a larger concentration of type II fibers? only if they're in a sport that requires quickness and explosive moves. but it seems it would be detrimental to your freediving performance.

strength training with weights will do this. lower reps and heavier weights will increase the percentage of type IIa fibers in your muscles. plyometrics and explosive-movement weight training will increase type IIb fibers. someone who is well conditioned can recover quicker after using these fibers primarily, but all that means is that they are "conditioned" to recover faster. they still go through quite a bit of oxygen, just more efficiently.

so, my suggestion if you want to increase your performance underwater is to stick to circuit training with light weights and get in a pool and do tons of laps. get your muscles used to slower, more controlled movements. this will eventually increase the type I fiber percentage, and will allow your body to remain in that aerobic state for a longer period of time while diving. and like everyone's said... 'you'd never get tired if it was purely aerobic.'

since the type I fibers produce little lactic acid, it seems logical that one would prefer to use them as much as possible over the other types.

happy flexing,
No wonder!


No wonder freediving doesn't come easy for me. Thanks for putting things in perspective. Obviously my body is full of nothing but fast twitch (oxygen burning) fibers. All through my life I've participated in sports that epitomized quick powerful bursts of energy. In high school I ran track as a sprinter and a pole-vaulter, before that it was youth football as a running back, and in collage I played rugby (also as a back). To top it all off I ended up as a National level competitive bodybuilder. I've always sucked at cardiovascular activities. Even in my prime, when I was swimming competitively on 2 swim teams and running track year round, a four-mile jog would kill me! Recently I started playing underwater hockey (BTW, kick ass sport for freedivers) to hopefully try to get in some kind of aerobic shape before the spearfishing Nationals and Worlds. Maybe it will help somewhat. I heard it can improve recovery time.

Scott Turgeon
West Palm Beach, FL
Follow the animal masters

The question of which muscle fiber type is best is complicated. The easiest answer may be (as usual), to look at seals & dolphins. I read that seals have almost equal amounts of fast & slow twitch fibers, and that the fiber ratios were not much different in their swimming muscles vs. non swimming muscles. Interestingly, the biggest variations in fiber types were actually between different types of seals.

Eric Fattah
BC, Canada
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