A freediving hang is a deep static. They are best practiced while diving with a line at 10 – 15 m depth (and always with a buddy). A deep static has some amazing benefits for your body.
How to do a freediving hang?
A freediving hang can be performed simply by taking a line diving rig (a float, line and weight) into the water. Pull down until your desired depth and wait there. I usually simply hold the rope with my hand, first upside down if that is the way I neutrally float at that depth and after a little while I move myself to a ‘right side up’ position.
Why is a freediving hang beneficial?
The pressure at depth makes gases in your body react differently with your tissues and cells. Let’s say your pull-downs remove a few percent of oxygen from your body and if done on dry land you would be left with 18% oxygen in your lungs. At 10 meters depth this oxygen will react at twice the rate (2 atmospheric pressure). It has exactly the same effect as breathing 36% oxygen.
“Gas reaction rates are proportional to its partial pressure”
What effect does a hang have on the body?
This is probably a personal experience, but for me it is a combination of physical and mental relaxation. The physical part probably comes from increased oxygen perfusion within the body. Oxygen does not enter all parts of the body naturally. Especially when you have injured muscles (or tight muscles) where blood flow is reduced, these will not be as oxygenated as a normal muscle. A massage increases blood flow and hence oxygenation. A hang will increase the oxygen available simply because of the pressure under which it is allowed to react within the body. The mental relaxation is similar to the feeling in a static at the surface. However, a deep static is more comfortable than a shallow one simply because the lungs are compressed and it is more quiet. I am better able to listen to my heartbeat when underwater. Also… it is nicer to have a look around at depth.
Keep it safe
Make sure you practice your hangs with a buddy, use a dive watch or a timer at least, and practice them on a line so that your buddy knows where to find you.
Edit 14th of June 2016. AIDA released an announcement warning freedivers of the dangers of deep hangs. Although deep is unspecified, prudence dictates I reiterate the warning here:
Warning on DEEP HANGS! Please be advised this is a very dangerous form of training even for experienced freedivers. It requires stricter safety protocols we didn’t test yet. Given this is a new phenomena, these protocols will need to be developed if this type of training gains favour in this community, but for sure we’ll need more than the usual deep diving safety. We are particularly concerned for the less experienced divers that may be tempted to do what they see on Facebook and we ask an increased level of responsibility from our athletes concerning their public posts. (https://www.facebook.com/AIDA-announcements-742763479156658/?fref=ts)
William Trubridge his comment on this post provides us with some perspective:
Like any exercise that involves depth, deep hangs have associated risk.
To introduce perspective, the following activities would all be ranked as significantly more dangerous:
• NLT/VWT/DPV freediving
• Cave freediving
• 120m+ FIM
• 100% O2 dynamic
• Deep spearfishing
There is no substitute to increasing a broad level of awareness, understanding, and adaptable safety strategies, in the individual freediver and the sport in general.
According to my log, since 2008 I’ve done 68 maximal hangs between 50-60m. In all of these I have felt entirely in control, and only on one of the 68 have I had a brief surface blackout. Deep FIM/CWT freedives are more precarious, and I expect the other athletes who have done both would agree.
The difference is not that a deep hang is more dangerous, but that it is more accessible to a less-experienced freediver. They may be able to emulate it, while not possessing the “broad level of awareness, understanding and adaptable safety strategies.” That shortfall is the problem, not the activity itself.
For now though, I will accept AIDA’s advice, and include a warning on any posts about deep hangs. I’d also advise the following safety protocols to be considered.
1. Don’t attempt any hang deeper than 50% of your maximal CWT/FIM depth, but start with more conservative depths (e.g. 30%)
2. Use a lanyard and counterballast system, and make sure your lanyard cannot entangle at the bottom while you are there.
3. Safety divers should have a clear idea of maximum dive time, and activate CB if they don’t detect the beginning of your ascent in line with that dive time. (e.g. if your max total dive time is 3 minutes, and it takes you 0:45 to ascend then they would activate CB at 2:15, if they hadn’t yet detected pulling on the rope).
Maximum dive time shouldn’t be more than 10–15 seconds longer than your previous longest clean dive to that same depth.
Finally, please note again that Freedive Wire is not a teaching institution. We merely provide news to the freediving community.