Sunday, September 20, 2020

Crossfit Encouraging Deadly Hyperventilation As Part Of Training

Updated: 18:29 UTC/GMT 13th August


Our friend Roman Castro from SpearoBlog has brought to our attention a potentially dangerous and deadly pool training technique on their Facebook page and Twitter.

The athlete in question – Ben Smith who is an elite crossfit athlete – is seen to be hyperventilating and then swimming a length underwater.  The acronym EMOM means “Every Minute On the Minute” which encourages athletes to continue this exercise as quickly as possible and repeat every minute with no or little rest.

Freediving safety basics show that with hyperventilation and no rest period will lead to Shallow Water Blackout Hypoxic Blackout – which if practicing by yourself can be fatal.

Elite athletes with training, aware of the dangers and supervised properly (as it seems Ben was in this case) are not the danger – the concern from the Freediving community is encouraging hyperventilation and then swimming consecutive lengths of a pool with little or no training or supervision is designed to end in tragedy.  Proper education and awareness of risks is what we would like to see from Crossfit.

RELATED: What Is Hyperventilation And Why Is It Such A Bad Idea?

The video has garnered 600 comments on Facebook already, many from Freedivers explaining how dangerous the video and exercise is.

If you are concerned about this video you should respond to the Facebook and Twitter posts and direct people to as well as your local Freediving class provider.

Stephan Whelan
Stephan Whelan
Stephan is the Founder of His passion for the underwater world started at 8 years-old with a try-dive in a hotel pool on holiday that soon formulated into a lifelong love affair with the oceans. In 1996 he set up and helped grow the site to be one of the largest diving websites around today.


  1. So you’ve never done shotguns (25m underwater swim) on the swim team growing up, or hypoxic sets? Not a crossfit invention…

  2. You can’t really tell from the video how much hyper he is doing. A lot of freedivers do 2 or 3 “deep purge breaths” before each dive. That may be all he is doing.

    • It’s a short video however the concern here is the mass audience with people doing hyperventilation prior to swimming or diving without understanding the risks or safety protocols developed by the freediving community to safeguard people in water.

  3. We need to be clear on terms when discussing safety and ensure we understand what goes on in our bodies in order to dive safely. It is impossible to have a shallow water blackout in a swimming pool. Shallow Water Blackout is a specific term which refers to the situation that occurs through overuse of oxygen at depth and is a function of the change in pressure from deep to shallow water causing a sudden drop in the partial pressure of oxygen in the lungs.
    Blackout however can occur in the pool when oxygen levels get too low and is far more likely following hyperventilation.
    It should also be noted that someone doing sets of timed 25m lengths quickly while training (probably not for Freediving) would be breathing hard between lengths, this could not be considered hyperventilation as it is necessary breathing for the effort being exerted.

  4. So, the guy filming the swimming would just watch him drown? Your post is completely link bait and adds nothing to the conversation.

    • The issue is not Ben Smith but crossfit are encouraging a “potentially” dangerous activity without giving advice on how to be safe to the masses of people watching their videos. Exactly how is our concern with people’s safety in the pool (something we know a lot about from the freediving world) a “link bait” post?

  5. I’m a former collegiate swimmer. My college coach once had us do 19×25 yard swims underwater on :30 (meaning you had 30 seconds to complete the length for the non-swimmers). Having a minute to do the same thing would be a luxury. This article is ridiculous.

    • Becky – just because you did it in college it does not make it a safe practice. However you were likely well supervised whilst doing those training lengths in college. As i’ve said in the above comments our concern is around the general public (and mass appeal and reach of Crossfit) getting potentially dangerous ideas without giving context to how to do the safety correctly.

  6. Stephen,

    Do you have an ax to grind with CrossFit? You’re in the deep end here and need to do a little bit more research.

    The point of an EMOM isn’t “with no or little rest” it’s actually the opposite. Rest time is built in to allow for consistency and maintaining intensity. Ben Smith traverses the pool in less than 30 seconds. That’s a rest of 1:1. Pick up at S/C text book. 1:1 is generous for an aerobic activity.

    Ben Smith is also the fittest man in the world. I think he’s safe.

    • We are only highlighting the risks of doing hyperventilation followed by back-to-back exercises. Our concern (as i’ll repeat from various times above) is the mass reach of crossfit videos without explaining how to do an exercise safely. People will see this, practice it by themselves and put themselves in danger. It is a well known fact in freediving that you should have a min 2 minute rest period for every 1 minute of breath hold you do. From a freediving perspective this exercise is potentially deadly. I am not saying Ben Smith is in danger nor commenting on how fit he is – I am commenting on the danger of highlighting an exercise that could kill you if not done properly or supervised properly. A simple link to some advice and education would have been sensible.

  7. I’ve been doing crossfit for over 3 years and have never done it in a pool. The article says “Crossfit encouraging” but this just looks like some guy in a pool doing some strange breathing exercises, what does this have to do with Crossfit?

  8. The “crossfit encouraging” is a direct result of the Facebook video and Twitter video posted by the crossfit account showing a potentially dangerous and deadly exercise regime. All of which is highlighted clearly in the post above.

  9. Poor and misleading title … encourages deadly hyperventilation as part of training. Please show responsibility in writing and reporting. Explain how Crossfit encourages deadly hyperventilation and support it with an explanation of what exactly is deadly hyperventilation. I do Crossfit, am responsible in my training, and am very open to listening and learning what not to do, seriously. Also spearfish, so your explanation may help in that endeavor as well.

  10. Folks – i’ve made essentially the same response several times in the comments. Please read the post, read the comments and my responses. I won’t be commenting again to similar comments.

  11. Glad to see that, at least in this article, we are getting rid of the term “shallow water blackout.” It is imprecise and confusing as there are almost as many definitions as freedivers.

  12. Hypoxic Blackout and Shallow Water Blackout can happen to anyone, no matter how great of an athlete they are or how physically fit they are. CrossFit took to their social media account to promote and encourage an exercise that is potentially deadly, without taking the time to share how to perform underwater training drills SAFELY. Back to back underwater drills with little rest along with hyperventilation is a recipe for a quick and silent DEATH. Our organization, Shallow Water Blackout Prevention, has a team of aquatics experts who understand the dangers associated with this type of training, and it is their goal to warn elite athletes and the general public of these dangers. (This team includes Michael Phelps and his coach, Bob Bowman.) Our problem with CrossFit is not that they encourage underwater training, but that they are doing so without informing their followers of the proper safety precautions that should be taken. If you question the validity of our concerns please visit our website and read some of the stories of how many experienced athletes and swimmers have fallen victim to this phenomenon and tragically lost their lives. This is not “link bait” – this is serious, lives have been lost and will continue to be lost if athletes do not heed these warnings, educate themselves and train safely. If you have any questions please feel free to contact me and I will forward your question to our board of directors. Email me at directly at [email protected] -Britt Jackson, Executive Director

  13. Absolutely amazed at how vehement people are regarding a couple of things: First, the difference between “Hypoxic Blackout” and “Shallow Water Blackout”, which is fine to point out, but DB quoted the article…so the original text is not from DB, but rather, the authors of the original article. did DB add/correct/illuminate aforementioned differences between the two terms…yes. Is the point that there are activities that can be dangerous and therefore need some safety guidelines and awareness? Yes. The vast majority of athletes I have known in 30+ years of being an athlete are stubborn, pigheaded, driven, determined, focused, and absolutely certain of their own immortality…it’s all well and good to worry about that other fellow, but I’LL BE OK. So, hold the troll…I have competed in martial arts at the HS, Collegiate and National Levels with the US Military, I have been a diver for 35 years, a swimmer for as long, a triathlon and marathon competitor and I think I get to have an opinion here…and I’m talking about myself as well. Am I guilty of doing 25m breath hold lengths in the pool, without an adequately trained and briefed safety diver/partner…absolutely. Is it smart? Absolutely not…and I have dodged the bullet a million times. The article title and content are quoted…DB did not generate them. The article points to a real danger…regardless of how “fit” someone is. Many people die each year in pools with other swimmers, lifeguards and spectators watching them doing that “cute breath hold thing”. So hold the righteous indignation…the purpose and drive of forums like DB should be to educate and inform…and if you don’t agree, then at least keep in mind that the purpose wasn’t to poke YOU, but to raise awareness…and if one person is made safer or more aware, then the article did it’s job. Visit Britt Jackson’s page and check out and remember, all our personalities aside, we are all part of a very special fraternity and we do not want anyone not coming home after a dive or training session.

  14. I left a great, detailed and lengthy comment a few minutes ago…and I think I exceeded the character counter. So here’s the short version: DeeperBlue can’t just change the title or content of an article it is quoting or re-posting. When you guys find that allowance in a style guide let me know; I’ll apologize to all my journalism and education students.

    So, to all the cross-fit enthusiasts and swimmers that are getting upset over what they seem to perceive as an unfair attack on their beloved training regiment…take a breath (see what I did there?). The article points out a real, factual (though the mix-up in terms is quite unfortunate) and serious problem. There are people who hold their breath, swim underwater in pools and die….and that is with lifeguards, swimmers, friends and spectators there when they do it. Hypoxic blackout versus SWB aside, the point is that people can die without a properly trained and motivated safety watching what you are doing.

    I have been an “athlete for 35 years, with a remarkably unsuccessful baseball career, a moderately successful martial arts career at collegiate and national levels, a few things that were athletic with the US Military, have been diving and swimming for well over 30 years and even done a little of that “Crossfit” and some triathlon thingies like the Ironman. I know this about athletes…we are pig-headed, determined, driven, intrinsically motivated and unwilling to admit defeat…and we are also extremely and blissfully unaware of our own immortality. The “it’s the other guy who has to worry” mentality has led to the abrupt end of many an athlete’s life. From fellow rock-climbing enthusiasts to my fellow divers, I have seen too many great athletes die, or become permanently disabled due to a failure to calculate and understand the risks of a given activity.

    Gus (and gals), people die all the time doing underwater laps in pools. I do them, obviously many of you do them, we all think…what’s a 25M swim or two going to do? Well, maybe kill you. Hypoxic Blackout can happen with no warning, no outward signs, no chance of recovery if you don’t have someone watching you like a hawk. So let’s not get our collective feeling hurt because the article doesn’t meet some criteria in our minds…it illustrates a valid safety issue. I, for one, am pleased to see some more attention given this subject in the confident expectation that everyone who read the article will at least think and evaluate before swimming underwater laps again. Maybe one life is saved…and that’s a great thing!


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