Before I am sharing my experience in freediving without a wetsuit I would like to emphasize two principles concerning this subject:
1. The rather paradoxical fact that oxygen consumption is reduced during an apnea dive in cold water. This phenomena has been coined by Eric Fattah as HDS (Hypothermic Diving System).
2. The absolute necessary precondition for taking advantage of the Hypothermic Diving System is to keep the core body temperature high before getting into the water, also mentioned by Eric Fattah.
Last August I managed to dive to a depth of 36 m (118 feet) in a mountain lake called Attersee (Lake Atter), near Salzburg, Austria with only a pair of fins and a bathing suit. Noteworthy is not the depth by itself but the water temperature down there: 5°C (41°F). It wasn’t painful at all and I didn’t have to be “tough” to survive the dive but surprisingly it was a pleasant experience that I am planning to pursue next summer.
How did this happen?
I have had previous experience in diving without a wetsuit, but nothing remotely to being exposed to water temperatures of 5°C–10°C (41°F-50°F) for more than 60 seconds, as I have been in this 36 Meter dive. The accomplishement was partly based on preconditions mentioned below and partly on the serendipity of that day:
1, Previous experience: I have been freediving since 1969, and back in the old days it was pretty normal to dive without a wetsuit. I got used to the shock after passing the thermocline during our summer vacation in Croatia. Typically the water temperature that did await us at 30m (100 feet) was 15°-16°C (60°F). Those of us living close to Vienna have the famous Neufelder See at their disposal, a small lake about 40 km (25 miles) outside of Vienna, where most freedivers from the eastern part of Austria do their training sessions. Typically in the summer time the thermocline of Neufelder See is at a depth of 7-8 m (25 feet) after which the temperature would drop to 10-13°C (50-55°F). I remember that it used to be painful to spend more than 30 seconds below the thermocline.
2. Looking at the impossible: In 1978 I passed my CMAS *** SCUBA-dive examination near Seefeld/Attersee. Back then we had to do some drills on a 40m (131 feet) platform. That was the first time I have been diving in Attersee, a mountain lake near Salzburg, Austria. Back then the crystal clear and numbing cold water instilled so much awe that I wouldn’t even dare to think about freediving to that platform in a wetsuit let alone in a bathing suit! But I believe that many dreams start when we become specifically aware of something as being “impossible”. As of now this impossibilty is only 4 meters away after reaching 36 meters this summer with little effort. My next goal is to dive all the way down to that 40m platform (131 feet) without a wetsuit.
This impossibility stayed in the back of my mind since 1978 and occasionally I would dare to dive in Attersee down to 20 Meters (65feet) without a wetsuit. Back then I was too fearful, therefore I couldn’t fully “enjoy” the cold water. A scuba-station nearby used to display the water-temperatures at certain depths of the lake. These are the typical measurements in August, when the surface temperature reaches its maximum:
@Surface: 22°C (72°F)
@10 Meters: 10°C (50°F)
@20 Meters: 7°C (45°F)
@30 Meters: 5°C (41°F)
3. Realizing the dream: Friday, Aug 17 2012 was a day with perfect conditions with an air temperature around 30°C (86°F), no wind and calm water. On that day I didn’t feel like fixing the tears on my Elios-jacket from yesterday’s dive and then to struggle into it again. My core body temperature was high and spontaneously I decided to dive in my bathing suit. According to my SUUNTO the water temperature on the surface was 22°C (72°F). I aimed at a depth of 32 Meters and was successful immediately. To my surprise it was a very pleasant dive that I repeated on Saturday, August 18, when I reached a depth of 36 meters (118 feet).
4. The details of the dive: I purposed to relax at the moment that I would hit the thermocline. I planned to say to myself: “don’t fight it, just let it happen”. I don’t know if that helped to stop my thermogenesis (shivering) but all of a sudden I felt comfortable and warm. On my way back up, after being exposed for 60 seconds to water temperatures below 10°C (50°F) I felt a little cramp on my head and on my neck reminding me of the fact that the water was indeed freezing cold, but even that was bearable.
5. Evaluation of this terrific experience: Surprising to me was the experience, that this dive was hurting less than my previous dives at Neufelder See. Paradoxically the 5°C (41°F) water at Attersee “felt” warmer than the 12°C (54°F) water of Neufelder See. On top of that, I felt fresher after this dive compared to a dive to the same depth in a wetsuit, i.e. there was more oxygen left! The only explanation I came up with was the possibility that the colder water at Attersee caused a stronger reflex of the body to adapt to the cold, a reflex strong enough for the hypothermic diving system to kick in. In the hypothermic diving system two main factors prevent the body from entering into thermogenesis (shivering) in spite of hypothermia: a) a huge thermocline and b) the blood turning acidic during the dive. As a result the body saves oxygen.
It almost sounds unbelievable: to enter the 22°C (72°F) water with an ideal core body temperature of 37°C (98°F) is costing me more effort than crossing the thermocline and entering into 5°C (41°F) water, even though the two temperature drops are nearly equal (each one is a drop of approx. 16°C/29°F ).
6. Discovery of negative buoyancy: As a side effect of this experiment I discovered something peculiar about my buoyancy: I am too “heavy” in fresh water without a wetsuit! For most of us, who live in the temperate zone freediving in fresh water without a wetsuit means to encounter almost always water temperatures below 10°C (50°F). Therefore there exists comparatively little information about this subject and it is good to be advised about a potentially negative buoyancy.
In any case, compared to salt water (specific weight: 1,026) I am about 2 Kilos (4,4 pounds) heavier in fresh water, assuming my specific weight as close to 1 (78 Kilos and slender). With my lungs filled I get negative after 4 meters (10-15 feet) when freediving in fresh water without a wetsuit. In this case, according to my diving profiles my descending rate is about 1m/sec, however my ascending rate is only about 0,75m/sec which is a clear indication that I am “too heavy”. If I use my 3mm-Elios without weights my descending rate equals my ascending rate and I am perfectly balanced.
cheers
Gerald
1. The rather paradoxical fact that oxygen consumption is reduced during an apnea dive in cold water. This phenomena has been coined by Eric Fattah as HDS (Hypothermic Diving System).
2. The absolute necessary precondition for taking advantage of the Hypothermic Diving System is to keep the core body temperature high before getting into the water, also mentioned by Eric Fattah.
Last August I managed to dive to a depth of 36 m (118 feet) in a mountain lake called Attersee (Lake Atter), near Salzburg, Austria with only a pair of fins and a bathing suit. Noteworthy is not the depth by itself but the water temperature down there: 5°C (41°F). It wasn’t painful at all and I didn’t have to be “tough” to survive the dive but surprisingly it was a pleasant experience that I am planning to pursue next summer.
How did this happen?
I have had previous experience in diving without a wetsuit, but nothing remotely to being exposed to water temperatures of 5°C–10°C (41°F-50°F) for more than 60 seconds, as I have been in this 36 Meter dive. The accomplishement was partly based on preconditions mentioned below and partly on the serendipity of that day:
1, Previous experience: I have been freediving since 1969, and back in the old days it was pretty normal to dive without a wetsuit. I got used to the shock after passing the thermocline during our summer vacation in Croatia. Typically the water temperature that did await us at 30m (100 feet) was 15°-16°C (60°F). Those of us living close to Vienna have the famous Neufelder See at their disposal, a small lake about 40 km (25 miles) outside of Vienna, where most freedivers from the eastern part of Austria do their training sessions. Typically in the summer time the thermocline of Neufelder See is at a depth of 7-8 m (25 feet) after which the temperature would drop to 10-13°C (50-55°F). I remember that it used to be painful to spend more than 30 seconds below the thermocline.
2. Looking at the impossible: In 1978 I passed my CMAS *** SCUBA-dive examination near Seefeld/Attersee. Back then we had to do some drills on a 40m (131 feet) platform. That was the first time I have been diving in Attersee, a mountain lake near Salzburg, Austria. Back then the crystal clear and numbing cold water instilled so much awe that I wouldn’t even dare to think about freediving to that platform in a wetsuit let alone in a bathing suit! But I believe that many dreams start when we become specifically aware of something as being “impossible”. As of now this impossibilty is only 4 meters away after reaching 36 meters this summer with little effort. My next goal is to dive all the way down to that 40m platform (131 feet) without a wetsuit.
This impossibility stayed in the back of my mind since 1978 and occasionally I would dare to dive in Attersee down to 20 Meters (65feet) without a wetsuit. Back then I was too fearful, therefore I couldn’t fully “enjoy” the cold water. A scuba-station nearby used to display the water-temperatures at certain depths of the lake. These are the typical measurements in August, when the surface temperature reaches its maximum:
@Surface: 22°C (72°F)
@10 Meters: 10°C (50°F)
@20 Meters: 7°C (45°F)
@30 Meters: 5°C (41°F)
3. Realizing the dream: Friday, Aug 17 2012 was a day with perfect conditions with an air temperature around 30°C (86°F), no wind and calm water. On that day I didn’t feel like fixing the tears on my Elios-jacket from yesterday’s dive and then to struggle into it again. My core body temperature was high and spontaneously I decided to dive in my bathing suit. According to my SUUNTO the water temperature on the surface was 22°C (72°F). I aimed at a depth of 32 Meters and was successful immediately. To my surprise it was a very pleasant dive that I repeated on Saturday, August 18, when I reached a depth of 36 meters (118 feet).
4. The details of the dive: I purposed to relax at the moment that I would hit the thermocline. I planned to say to myself: “don’t fight it, just let it happen”. I don’t know if that helped to stop my thermogenesis (shivering) but all of a sudden I felt comfortable and warm. On my way back up, after being exposed for 60 seconds to water temperatures below 10°C (50°F) I felt a little cramp on my head and on my neck reminding me of the fact that the water was indeed freezing cold, but even that was bearable.
5. Evaluation of this terrific experience: Surprising to me was the experience, that this dive was hurting less than my previous dives at Neufelder See. Paradoxically the 5°C (41°F) water at Attersee “felt” warmer than the 12°C (54°F) water of Neufelder See. On top of that, I felt fresher after this dive compared to a dive to the same depth in a wetsuit, i.e. there was more oxygen left! The only explanation I came up with was the possibility that the colder water at Attersee caused a stronger reflex of the body to adapt to the cold, a reflex strong enough for the hypothermic diving system to kick in. In the hypothermic diving system two main factors prevent the body from entering into thermogenesis (shivering) in spite of hypothermia: a) a huge thermocline and b) the blood turning acidic during the dive. As a result the body saves oxygen.
It almost sounds unbelievable: to enter the 22°C (72°F) water with an ideal core body temperature of 37°C (98°F) is costing me more effort than crossing the thermocline and entering into 5°C (41°F) water, even though the two temperature drops are nearly equal (each one is a drop of approx. 16°C/29°F ).
6. Discovery of negative buoyancy: As a side effect of this experiment I discovered something peculiar about my buoyancy: I am too “heavy” in fresh water without a wetsuit! For most of us, who live in the temperate zone freediving in fresh water without a wetsuit means to encounter almost always water temperatures below 10°C (50°F). Therefore there exists comparatively little information about this subject and it is good to be advised about a potentially negative buoyancy.
In any case, compared to salt water (specific weight: 1,026) I am about 2 Kilos (4,4 pounds) heavier in fresh water, assuming my specific weight as close to 1 (78 Kilos and slender). With my lungs filled I get negative after 4 meters (10-15 feet) when freediving in fresh water without a wetsuit. In this case, according to my diving profiles my descending rate is about 1m/sec, however my ascending rate is only about 0,75m/sec which is a clear indication that I am “too heavy”. If I use my 3mm-Elios without weights my descending rate equals my ascending rate and I am perfectly balanced.
cheers
Gerald
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LOL