Location chosen wisely by Herbert ??

[Fred S.]

Coming weekend (july 27th) Herbert Nitsch is going to do some WR attempts in Austria. This is going to take place in the Millstätter See, a mountain lake at about 580 mtr above sea level.

When I was thinking about it, I realised that choosing that spot might perhaps not be ideal for record attempts:

1) Mountain-lakes tend to be very cold. So at geater depths, when the suit is compressed, there is no isolation from the cold. This cold cools the body down and for keeping the wright body temperature you have to use more oxygen.

2) At altitude the air is thinner. This means that full lungs at altitude contain less 02-molecules than at sea level.

3) Air pressure is lower at altitude. Water pressure is the same. So while descending the lungs are compressed quicker than at sea level, which for instance makes clearing the ears harder and the sensation of pressure on the chest starts at a lower depth than at sea level.

Any comments?

Fred

[Mad Max]

At the beginning I thought the same, but I heard that he was doing still 97m free immersion in the lake last week.
And for static he is now coached by Dieter Baumann like in Ibiza last year. So I think it is still possible for him to get the record.

[Silver]

The pressure is lower both in air and in water at altitude. Because of this the lungs will not get compressed any quicker.

Magne

[Fred S.]

If the air pressure (at altitude) at the surface is 0,9 ATM, the pressure at a depth of 27mtr. will be 3,6 ATM (0,9+2,7). So if we have an air filled balloon with a volume of 10 liters at the surface, the volume at 27 mtr. will be 2,5 liters (3,6/0,9).

At sea level, if the air pressure is 1,0 ATM, the same balloon would be compressed to a quarter of it’s size at a depth where the surrounding pressure equals 4 times the pressure at the surface, and that is at 30 mtr. (1,0+3,0=4,0)

Doesn’t this example show that the lungs are “squeezed” quicker while freediving at altitude ??

[fpernett]

I think Herbert is right.
First, That lake is the place where he trains. We all know that freediving in a familiar place is a great psychological aid. He knows the pros and cons of that lake, is sorrounden by known people and that is a very good help for a WR attempt. I read the diary of the attempt in Tenerife and He doesn't feel comfortable. The same happen with E. Fattah, He couldn't make the world record in Florida (He never feel right there), but He made it in Canada in darker and colder waters. I think Herbert is going to make it.
Second, the physiology of altitude freediving isn't so simple.
-Usually at altitude you are freediving in lakes (Freshwater), and that is the first difference: 10 meters of SW= 1 Atm., 10.3 meters of FW=1 atm.
Using the ballon example:
27 mfw= 2.6 atm + 0.9 atm =3.5 ATA
V2=P1*V1/P2=0.9 ATA * 10 L/3.5 ATA= 2.57 lts ;
At sea level:
P2=P1*V1/V2=1 ATA * 10 L/2.57 L=3.89 ATA ;
3.89 ATA= 28.9 msw
That means that the volume at 27 mfw is the same at 28.9 msw for that altitude. As higher the altitude the difference gets bigger. For example I train in a lake at 3010 meters osl, and a 30 meters inmersion there is like a 45 meters at sl. So, it's obvious that freediving is harder at high altitude.
-We have to remember the altitude adaptations of the body are different from a person who has just arrived to the altitude from one who is living for years or was born there.
-The colder water makes more efficient the diving reflex, in fact Fattah has briefly talk about the Hypotermic Diving System

Of course the lake inmersions are quite harder than sea inmersions but this doesn't mean that he made a wrong decisition, He will use the place, that better know

[Silver]

look at it this way: when you are at altitude you lose preassure.
30m at sea level give 4atm, 30m at altitude (0.9atm at surface)
give 3.9atm. 10l at 4atm give 2.5l, 10l at 3.9atm give 2.564l.
The lungs will compress slower at altitude.
Magne

[fpernett]

Hi Magne,
I don't think about that in faster or slower compression. You have to think about it as Equivalent Depth.
The "speed" of compression isn't real. According to Boyle's Law for every pressure change will happen a volume change in the opposite direction.
Is not the same 30 m of sea water than 30 m of fresh water and the changes in barometric pressure also affect the ATA at that depht. Is not the same 30 mfw in a lake at 500 meters over sea level than a lake at 3000 meters over sea level.
The fact is that the changes will be the same at equivalent depth, so you can't compare it.
By the way I developed a formula for training purposes,

This is the formula:

Equivalent Depth=(Dl/0.131 x Bp) x 100%

Where Dl is the Depth achieved in lake in meters
0.131 comes from 760 mmHg/100%
And Bp is the Barometric Pressure at the lake altitude in mmHg

The Equivalent Depth is in meters of sea water.

If we apply the formula to the World record in CW in lake and sea, and fortunately the same freediver holds the records, we have:

ED=72 meters/(0.131 x 612.22)x 100
ED=89

If you say that your lungs compress slower at altitude it means that the boyle law changes with altitude, and that is wrong. What changes is the presure not the rate of change.

[Bill]

Hey Guys
I can't stay out of this one. Comparing apples and oranges again, I think. Correct me if I'm wrong. I may get mixed up with metric and English stuff too.
A column of air, one square centimeter and thirty kilometers high weighs about one kilogram, 15 pounds (edit: per square inch), and is measured in pressure. A column of water, one square centimeter and 10 meters high weighs about the same (sea water is 2% more).
If we start at sea level (one kilogram/square cm) pressure and descend to 10 meters (another k/cm^2) the volume in our lungs will be 50%.
If there was a lake at the highest point in North America, the air pressure at the surface would be half (500 grams/cm^2) but the water would still be about the same weight and at 10 meters the total pressure would be 1500 grams/cm^2 and our lungs would be 33% of surface volume.
Having said all that, for an altitude of 500 meters, the 3% less air could easily be offset by familiar surroundings.
Aloha
Bill

[Silver]

Read this !
http://www.ivydene1.demon.co.uk/dive/altitude.htm

[Bill]

Silver
Thanks. Good reading. Love crunching numbers.
Aloha
Bill