Almost all decent freedivers and respectable coaches will perform some type of exhale diving as part of their depth training programs. Depending on who you ask, you’ll get different answers regarding how often to engage in exhale training, how much you should exhale, where you should practice it, and what it’s actually good for. 

Like anything, there are extremists on both sides.. Some will say that exhale diving is useless and unnecessarily dangerous, and some think is the only way to dive. 

My exhale diving story started with an ‘exhale extremist’: Sebastien Murat. Seb’s opinion is that, based on the fact that the deepest diving mammals; sperm whales, widdel seals, and Cuvier’s beaked whales all dive on exhale, so should we. He advocated that a passive exhale, we call this lung volume ‘FRC’, is the ‘only’ way for humans to safely dive to depth. Personally, I thought this was crazy… but also really cool. 

Here’s a video of Seb explaining the ‘physiology’ and ‘theory’ (use these terms lightly) behind why he thinks exhale diving is the best;

This fascination eventually, after a few years of experimentation, turned into a (temporary) full-time switch to FRC diving. I wanted to see how far I could take it (I’ve achieved 50m bi-fins on FRC.. so not too bad) if I only dove on exhale for a while. I also theorised that: If I ever want to switch back to inhale, no problem. It might take some getting used to, but at the very least my equalization will be significantly improved from all the exhale practice right??? Well, sort of. 

After my exhale-only period, the switch back wasn’t so simple. Up to 50m everything went very well. It was easy to equalize, my confidence was through the roof, and the dives were extremely easy. So I tried 60m.. and ultimately suffered a trachea squeeze. You see, exhale diving ‘full time’ makes some things easy, and some things very hard. Fighting buoyancy, which you never have to do on exhale, is one of those hard things.. 60m became a temporary limit for me, and I needed to start over, re-learning to descend without getting tense. 3 months later I ended my season at 70m.

This was over a year ago, and after comparing my training then, my training from before the exhale-only period, my latest training period where I only included 2 exhale sessions, and not to mention countless conversations with other freedivers about their exhale training, I’ve finally formulated my opinion.

You should be exhale diving as much as you need to… (Well that’s confusing) 

Most coaches and athletes will have their own opinions about how to program your exhale training into your cycles, and what exactly it trains, but at the end of the day it really depends on what you’re struggling to train effectively with normal inhale diving. Exhale training has its benefits in these cases. It’s very hard to do multiple deep dives in a session to train equalization, but you can do countless full exhale dives to 15m and get the exact same technical benefits, for example. Of course, there are pros and cons to everything, so you need to take the time to make the right decision for you.  

Making these decisions depends on what you need to work on in your diving and whether or not exhale training can help achieve it. So what does exhale actually train? Well, there are three main things; equalization, hypoxic tolerance, and chest pressure. Let’s break them down. 

Equalization:

Exhale training is a great way to train your ‘deep equalization’ because the main variable that affects EQ at depth is your final lung volume. Starting your dive with a lower lung volume means that you’ll reach these minimum lung volumes at significantly shallower depths. Shallower dives means more dives per session and overall more time spent training your equalization. 

Where a 70m diver might only be able to do 1x70 in a single session, they could do 5-10 30m FRC dives. In both cases, lung volume at depth is going to be very similar, and therefore they could accumulate much more EQ practice this way.

The main possible cons of exhale EQ practice is that it always seems to be easier (relative/equivalent depth) to equalize on exhale. It’s a generally more relaxed ‘mode’ of diving, and most divers struggle to apply the same techniqnical quality on their full lung dives. Exhale can supplement your full-lung EQ training, but it cannot replace it.   

Hypoxic Tolerance:

Another benefit of performing breath-holds on exhale is that you can become hypoxic much quicker, and with greater ease. A diver might need to do 5:00 inhale statics to reach the same level of hypoxia they could with 1:30 on full exhales to RV. Mentally, these shorter holds are much easier to achieve and more reps per session can be done, allowing the diver to accumulate more overall exposure to hypoxia. 

Using exhale in depth can have a positive psychological effect on breath hold as well. I personally noticed that after doing regular 1:30 dives to 15m on RV, suddenly 3:00 recreational dives on inhale became very easy. Having much bigger lungs at depth possibly tricks the body into feeling safer, and urge to breath can almost disappear entirely.  

Possible cons of exhale hypoxia training are that you can become accustomed to the shorter dive times. Mentally, becoming hypoxic on a 1:30 static is very easy, but get ‘too’ used to this and +3:00 might feel like a long time, despite having more available O2. Another theoretical con of this kind of training was brought up by Eric Fattah during his exhale-only days. He theorized that your body adapts to the lung volume you use more regularly, though a mechanism called the ‘oxyhemoglobin dissociation curve’ by changing your 2,3-DPG levels. Noticing a pattern with the cons of exhale training yet? 

More here;

https://en.wikipedia.org/wiki/Oxygen%E2%80%93hemoglobin_dissociation_curve

https://forums.deeperblue.com/threads/raising-2-3-diphosphoglycerate-levels.51901/

Chest pressure:

If you are a freediver who struggles with the feeling of chest pressure, or have possibly had issues with squeezing, exhale training can offer a way to deal with this as well. Just the same as equalizion, lower starting lung volumes mean reaching minimum lung volumes at shallower depths. This allows for more time spent with lower-than-RV lung volumes, therefore more time for your body to adapt. 

The possible cons of this is that you can easily over stress your lung tissues. Stretching works by slightly damaging tissues allowing them to heal stronger. Doing too many dives below your residual volume means that you might suffer from accumulative-squeezes, damage gathered over multiple low lung volume dives. With inhale, we cannot do as many dives to such low lung volumes on the same session, as the depth required to do so is too great for many repetitions.  

A second issue is sensation. Exhale generally results in a descent that is extremely easy and relaxed, with almost no buoyancy to overcome. Again, getting ‘too’ used to this, needing to fin against inhale-buoyancy can produce lots of tension, actually increasing your risk of squeezing.  

That’s the very distinct issue with exhale training…

Do it, and you will get good at it. In all three cases, you can start to “over” adapt to exhale, and actually lose performance on inhale. This means that exhale training cannot replace inhale training, only supplement it. 

Like I said, we need to do as much exhale training as you need. I think we should all include some exhale training, but be very careful to weigh out the benefits and negatives.  

Weighing the Pros & Cons

How much, and what type, of exhale training you should be doing depends on your personal circumstances. 

A freediver who is limited to a 30m training ground will benefit more from exhale practice that a freediver who has 100m regularly available to them. The principle is simple. If you want to get good at deep inhale diving, you need to be doing deep inhale diving. 

However, if you cannot do much ‘deep’ inhale training (you’re mostly limited to 30m for example) then adding in more and more exhale training will give you the benefits that you need to make the most of your next trip to deeper waters. Preparing with frequent, but not exclusive, exhale training can accelerate the process of getting back to near PB depths, meaning you’ll ‘waste’ (use that term lightly) less time on your next 3-week diving holiday to the Red Sea or the Philippines.  

Generally speaking: The more often you can dive deep, the less often you need to supplement with exhale training.   

Consider these things when designing your next training program;

Are you struggling with hypoxia or chest pressure?

Are you trying to learn a new equalization technique?

Are you limited to depths that are significantly shallower (<25%) than your PB?

If the answers are no, no, no, then there’s no need to do very much exhale training. Of course it’s good to do some and keep your skills sharp and your workouts fresh, but it’s not very high up on the list of important things to do.    

However, if the answers are yes’s, then by all means.. Do your exhale training, it will benefit your diving a lot.