• Welcome to the DeeperBlue.com Forums, the largest online community dedicated to Freediving, Scuba Diving and Spearfishing. To gain full access to the DeeperBlue.com Forums you must register for a free account. As a registered member you will be able to:

    • Join over 44,280+ fellow diving enthusiasts from around the world on this forum
    • Participate in and browse from over 516,210+ posts.
    • Communicate privately with other divers from around the world.
    • Post your own photos or view from 7,441+ user submitted images.
    • All this and much more...

    You can gain access to all this absolutely free when you register for an account, so sign up today!

SWB warning bells ?

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.


Well-Known Member
Apr 21, 2003
Hi All

After reading a comment in the forums about smoking causing a 'delay' in the warning signs of an impending SWB, I was just wondering what the early signs are ? I do'nt smoke, and tend to cut my bottom time to staying very much inside the 'conservative-zone'. ( Obviously getting more conservative the deeper I'm diving.)
I surface well before any contractions etc, am I being too conservative, and are there any accepted 'early warning' signs ?

Thanks all, have a great weekend 'down there'.

Jeff ;)
Feeling way too happy as you are ascending is one sign.

I have only had one mild LOMC in the water. I remember looking at the sun on the water as I swam to the surface, breaking the surface with a slight buzz feeling like a million bucks, looking at my buddy (Volodya that particular day) and thinking the this moment was the absolute shittinist -- then I realized that my right leg was making a slow, involuntary motion. Imagine a dog's leg when you scratch their tummy and you get the idea.

So having a burst of euphoria in the last 15 feet of surfacing is a danger sign.
the bottom line is that every time you hold your breath and dive, you take a chance. Erik Y.

Yep, the Guru of Group Hugs is correct. From my experience I get a "full" feeling on the way up and feel really good about life in general, which for me never happens, so there's definitely something amiss :head Then that "warm and fuzzy" takes a hike and I'm dynamic-ing for all the fins are worth, streamlining, getting a hold of the weight buckle, mask pumping...

At that point , my mask is off at the surface and I'm concentrating on venting as much as possible and mentally counting my fingers and toes. If the number is more than 19, I breath some more and look for my buddy.

Must be the age... ;)


Last edited by a moderator:
I agree with most of what Erik said, but I believe that we loose the spearo's because it is better to hunt alone without anyone to scare the fish. Yes one does push the limits in spearing, but without really realizing it. You can loose trck of time while trying to lure a fish to you or stalking one and as Erik pointed out if you weren't 95% or better you could run into trouble.


Not all divers feel euphoric as they ascend or surface, I for one feel really sh*%y when I know I'm going to samba. Everybody will feel different things, just learn what it is that happens to you and try not to get to that point during a dive.

'surfacing well before having any contractions'.... that's good, *if* you're not hyperventilating before diving. but what is hyperventilation - how long is a piece of string etc etc...
well, i was discussing my breathing rate for deep dives with my buddy the other day, and we think my breathing rate is about 2 breaths a minute, lasting for 2-3mins max. so... about 6-7 very long slow relaxed deep breaths, with optional packing at the end, but definitely no purges or washes or flushes or super-vents or whatever the latest term is. :)

probably the best advice is to dive, dive, dive and then go dive some more. sooner or later you'll begin to pick up on those subtle signals, and notice them much more.
once in a while, when you're feeling good increase your perceived effort by 5%, and see how the dive goes. if you increase your effort slowly enough, sooner or later you'll realise that you are edging closer to your limit...
The one theme that I'm seeing here is that you need to hit the limit to know where it is.

I agree that euphoria is not the only symptom of a troubled ascent. If I get tapped when I'm deep, I can feel when I'm running out of gas on the way up - and that feels pretty crummy (at that point, I start thinking about setting criteria for ditching the belt, grabbing the line to haul up etc.). Last time I felt this way was on a no fins attempt, which I turned it into a free-immersion for the last 15 meters.
Thanks for the feedback everyone. I guess I will learn my own signs as I get more experienced, hopefully without any drama.

I have been taught you will never have a warning sign, when your O2 level in your blood gets below a certain level, your brain will shut off without warning. It will almost always happen shallow because at deeper depths, the partial pressure of O2 is higher.
The number one rule of scuba diving is never hold your breath, the number one rule of freediving is never dive alone.
I have passed out at the surface after a dive and my buddy samba'ed at about 15 feet. I didn't believe I had passed out until someone handed me my mask, which I knew I never removed.
Last edited:
I like deeperblue.net and I like this newbie forum. I actually started freediving when I was 11 years or so -- we called it skindiving back then -- but practically stopped alltogether when I was 17 or so, so I still consider myself a newbie.

I began skindiving again after I got scuba certified but then stopped again after hanging out here in deeperblue.net and reading about Shallow Water Blackout. I became a little scared of the idea of skindiving alone. I always go alone because of serious lack of diving buddies -- at least the kind that are interested in diving the same times I am.

I don't push myself or stalk anything when down, but I can stay down for a while and sometimes notice it seems like suuuuch a loooong time while heading for the surface. This has gotten me a little scared and so I've backed off.

Is this only a problem when pushing your limits? Are there safe amounts of bottom time a person can stick too, or rules of thumb you can tailor to your own ability level? Any recommendations for solo skindiving?
I don't stay down long at all, and I always feel euphoric on the way up! Even the real short dives. It feels like a meditation high. When I feel the urge to breath I unfasten my belt immediatly. I've never lost any muscle control, and the only contractions came during dry-land apnea training. And all that's because I rarely have a reliable partner.

And I'm confused: what's the risk zone for SWB? I've read 15 meters- deeper than I usually dive- and 15 feet on up to the surface. Several posters say they've blacked out at the surface. Does this phenomenon occur in dives under 30 feet?
Originally posted by ruddyduck
: what's the risk zone for SWB? I've read 15 meters- deeper than I usually dive- and 15 feet on up to the surface. Several posters say they've blacked out at the surface. Does this phenomenon occur in dives under 30 feet?

BO can happen at any depth. Whether it's Shallow or Deep Water Black Out or at the surface is a matter of mechanics,and sometimes semantics. In every case we're in a world of hurt!
Erik Y.
Strangely.. warning bells are exactly what I get... I hear bells ringing in my head just before a black out or samba. If its like tinnitus I can usually get a grip on the situation. If its like church bells I have had it!

I also get a really strong metallic taste in my mouth when I know I am near the edge.

Thank god I havent felt any of these for a while

DeeperBlue.com - The Worlds Largest Community Dedicated To Freediving, Scuba Diving and Spearfishing


ISSN 1469-865X | Copyright © 1996 - 2024 deeperblue.net limited.

DeeperBlue.com is the World's Largest Community dedicated to Freediving, Scuba Diving, Ocean Advocacy and Diving Travel.

We've been dedicated to bringing you the freshest news, features and discussions from around the underwater world since 1996.