The inevitable contractions when you hold your breath

The inevitable contractions when you hold your breath

Contractions are the blessing and curse of every breath hold. Contractions provide an easy way to gauge whether your dive is coming to an end. Unfortunately your first contraction also marks the start of the struggle (the struggle phase of a breath hold).

Contractions help increase the output of blood from the heart. A strong contraction means temporarily increased blood flow to the brain. And that’s a good thing for a body that is trying to survive without oxygen.

So contractions have a use. Unfortunately the variability in brain oxygenation that the contractions cause, is negatively correlated with the duration of the breath hold. In particular, the duration of the struggle phase is shorter if you experience strong contractions.

The idea that strong contractions mean a shorter struggle phase makes a lot of sense. You probably expected this. So what can you do to delay the onset of contractions, or make them less intense?

 


Despite common belief, high CO2 levels are not the only thing that start contractions. Other factors are the degree of hypoxia, lung volume and the rate of gas exchange in the lungs and the shape of the diaphragm. Thankfully classic CO2 training, usually, works just fine. 

Don’t believe me? A lot of divers get contractions early doing a depth dive, but late in the pool – a result of the size of your lungs and the upward flexing of the diaphragm. Conversely, if you only train depth you will probably get early and uncomfortable contractions during pool training but not during a depth dive. 


 

There are a few different ways to become accustomed to higher CO2 concentrations. For example, long distance runners and cyclists have much higher CO2 tolerance than 100 m sprinters. Incorporating interval training with long (~2 min or longer) intervals of intense workouts are a great way to make contractions more comfortable.

The onset of contractions can be delayed by classic meditation & pranayama techniques. Try alternate nostril breathing or simply a measured pranayama. For example: 4:8:8:4 (4 counts inhale, 8 counts hold, 8 counts exhale, and 4 counts hold). You can use your heartbeat or time in seconds for the counts and change the pranayama as you wish. Make sure to maintain the breathing pattern for at least 5 min.

CO2 tables? They work, but you will eventually hit a plateau. Once that happens, you will need to experiment with different methods to find what works for you.

Never felt contractions? It is uncommon, but (despite the title), not impossible. I am not sure whether you should count yourself lucky or not…

The science:

Jaap

Jaap is a geologist by trade and a freediver by passion. Jaap wrote the book Longer and Deeper in 2018. His book teaches how to train for freediving and spearfishing on land.

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