Low on oxygen while getting high.
Can a freediver sustain the hardships of low oxygen at altitude better than normal people? Is there a training effect that will effect your breath hold ability?  As I planned to climb as high as possible in the Himalayas I was hoping to find this out. by: Sebastian Naslund

As freediver I have experience of low oxygen. Having practiced maximum static many times and suffering from unconsciousness several times due to low oxygen. In several different scientific tests I have ventured deep into hypoxia, as low as 40-45% on a saturation meter.

As a climber I am a novice, not having been higher than 1200 meters, not even owning proper trekking boots and actually loathing walking for the sake of just sightseeing. But the prospect of exploring the effects of heavy work at high altitude on my body was motivation enough. For the inheritance from my grandfather I bought a pair of custom made big fancy trekking boots. I borrowed my mothers high tech backpack and set of merrily to Nepal to meet freediver and climber Annelie Pompe.

2800 - into thin air
From Kathmandu we flew to Lukla at 2800 meters height. Already when examining the map on the start of the first day I knew it would be a challenge – I realized I probably in my life never walked longer than 20 kilometres on a day, and never upwards, and never with a load. Now I was to carry some 20 kilos several thousand meters upwards.
The higher you climb, the less oxygen in the air, or more alarmingly, less air pressure, which means the oxygen is not available, the partial pressure is not enough to get the O2 into your blood. Gas exchange is impaired.

On the second day we found ourselves in famous Namche bazaar - a place where most Everest expeditions pass by. This village clings on to the mountainside at 3400 meters. A days rest was advised in the guide books.

4000 - risk of altitude sickness
On the forth day we aimed for a village called Dole at 4000 meters. It is not advised to add 600 meters in a day. The last 200 meters up to Dole I felt like giving up, headache was pounding, heart rate 130 although taking one deep hungry breath every two steps. I was walking on the edge of lactic acid all the time. First symptoms of altitude sickness are: headache, fatigue, nausea, dizziness, lack of coordination.

I had decided that as long as I recovered (breathing and heart rate) when resting I would accept having only one of the several symptoms of altitude sickness. Altitude sickness kills people as low as 3000 meters. Exercising at these levels with constantly low oxygen may give you both brain damage and lung oedema. The feeling in my head at 4000 was similar to a test I did in a lab where they let me breath only 14% and 17% oxygen (instead of the usual 21%). At height the brain swells, causing headache and nausea.

Measuring oxygen levels
With us we had heart rate monitor and a oxygen saturation meter. These usually show 99% saturation at sea level and a resting heart rate of about 53. In Namche at 3400 I had a resting pulse of 58 and resting saturation of 88%. After one nights sleep at 4000 meters in Dole I woke up with a resting pulse of 60 and still 88% in saturation.

In the following days we added hundreds of meters every day.
Day 5: 4400 meters, saturation 82 %, heart rate 59
Day 6: 4750 meters, saturation 75%, heart rate 63
Day 7: 5100 meters, saturation 75%, heart rate 65

Saturation of 75% constantly! This is a value that I have after 4 or 5 minutes of breath hold.

Annelie checking saturation values below Amu Dablam

Cho La pass
On day 8 we crossed the famous Cho La pass at 5300 meters and that was one of my life’s biggest physical challenges. Breathing, breathing – one step, breathing, one step, stop, look up, breath, one step, adjust the backpack. Concentrating on finding footholds in the step rubble of stones leading up to the pass and the glacier beyond.
At 5000 meters you have only access to 50% of the oxygen normally found at sea level. How does the body react to that? It tries to adapt. It is called acclimatization and should be done at height without exercise, we where pressing on every day though.

The body has to do something, otherwise there will be damage. The main thing that happens is that the body starts building more haemoglobin. Kidneys release hormones that trigger production of red blood cells. These bonds to oxygen and your oxygen uptake increases. Further up the kidneys discard water to alter the bloods acidity. The body expels more CO2, again disrupting PH balance of blood. I am not a keen meet eater and to make haemoglobin you need iron – did I have enough?

Meter by meter, hour by hour, day by day

At certain altitudes we checked saturation and heart rate after sitting down and resting for two minutes on the path. On none of these occasions did my heart rate go below 90 even though resting for two minutes. The saturation was generally around 80-85% after the short rest.

We also tested a few of the local sherpas that carried load up the mountains. They usually got the same saturation levels as us - but their heart rate was generally lower and returning faster closer to resting values.

We also did breath holds
at different altitudes. In the mornings, after only 3-4 deep breaths. Above 3000 meter none of us managed breath holds longer than 1.40. The lack of oxygen and general exhaustion all days was not ultimate preparation. Also the body starts producing more CO2 at height which we felt in abnormally early and fierce contractions. Also the hard exercise (and constant cold) every day probably drove up the general metabolism. The onset of bradycardia was swift. At 4400 I did a breath hold with these characteristics:

At start: 80% saturation, 70 heart rate.
1.40 breath hold, contractions and 40 seconds.
Finish: 67% saturation and 44 in heart rate.

On day 9 we climbed Kalla Pathar to 5450 meter. After that I developed a throat infection and general cold which probably influenced all future values. Every morning in the lodges we woke up in temperatures below freezing point (our water bottles were icy every morning). Sleeping was often irregular with frequent onsets of sleep apnea. It seemed like the body accepted lower oxygen levels during sleep, but sort of boosted them up a notch during walking.

I discovered that I could reduce heart rate by 10% and increase saturation values by 5-8% by changing the way I breathed, using a modified yoga breathing that increased partial pressure (modified hook breathing). This usually gave me a headache, so I did not use it that much. Blood pressure usually soares at height, I measured mine at 4700 meters and got a value of 140/90.

On day 14 we set out to climb a 6000 meter mountain. Higher than any peak in Australia, Africa or Europe. That night we camped at 5600 meter experiencing snowfall all night. My resting values in the tent that morning where 71% saturation and a heart rate of 85. If this was in a hospital, doctors and nurses would come running. That morning we started climbing in darkness, leaving backpacks behind, only carrying crampons, rope, ice axes and water.

Imja Tse high camp

We reached 6000 meters feeling totally exhausted, experiencing a drunken feeling and a slow mind. After a 2 minute rest I again showed 70% in saturation and a heart rate of 95. That day we ascended 400 meters and then descended 1300 meters walking more or less constantly for 12 hours, most of it with heavy load. One of the most physical days of my life.

High altitude training
A known effect of breathholding is the contraction of the spleen - which releases its supply red blood cells. Apnea scientist Erika Shagatay wonders if this mechanism will be trained at high altitude and thus be stronger/quicker at sea level. Recently it was seen that spleen contraction occurs at altitude. Another question is if high altitude training will make you more tolerant to hypoxia - if you can functioning normal even at low levels of stauration.

The effects of high altitude training is the forming of more red blood cells (haemoglobin) which both bind O2 and buffers CO2. But as Erika points out, there are negative effects of high altitude training. Higher risk of infections, loss of appetite, muscle reduction. The good effects some claim lasts 14 days, others say only three days.

Coming down to more human altitude levels I was keen to know if my oxygen levels and uptake would have benefited from the training and the acclimatisation. I was hoping to beat a 6.50 result done a month earlier after 10 days on meditation retreat. Due to general exhaustion and the throat infection I could not really tell if high altitude training had helped. Back in Namche my resting values where a few % better (notably) compared to when coming up. Heartrate slightly down and oxygen values sligthly up.

<--One in then die if they try to climb up there.

The effect of high altitude training
One day after the trek back in Katmandu at 1200 meters level I started doing breath holds, but my metabolism seemed high for many days, contractions coming 25% earlier than usual. I was in a bad shape, infection with green snoot and even some traces of blood. Also limping due to a dogbite. I was also semi numb in the top all fingers for a week after coming down.

For the following ten days I held my breath every morning noticing no effect of any increase of red blood cells. During this time I loaded with c-vitamins and my infection showed signs of giving away. After a week I started eating some iron supplement (since I had not been eating meat for some time).

It was not until the 13th day after the mountian back in Bangkok at sea level that I saw some tiny signs of a altitude training effect. First day in BKK was bad, but then the next day: Heart rate slowed down below 60 in the morning, saturation went up from 95-96% up to 97-98%. A 25-30% delay of contraction onset, but oxygen seemed to drop at the same time as usual while breath holding.

Breath up of of 20-25 deep breaths during six minutes: contractions at 3.50 (earlier in the week always at 2.50). Saturation 90% at five minutes breath hold and heart rate of 50 at five minutes.
A visit to the doctor on the 11th day showed a blood pressure of 110/70 (on the mountain 140/90) and haemoglobin values of  144 (usually 155). So no training effect? Why?
1) To little time at height?
2) Iron deficiency?
3) Delayed response?
4) HB count may have increased, but also plasmavolume, thus not higher concentration?

Evaluation proceeds - this page will be updated...

17 days after coming down from spending 14 days above 4000 meters I returned to Sweden (sealevel). The oximeter directly showed 1-2% higher values. Resting at 98-99 (which is expected). Why had the Bangkok values also at sealevel been slightly lower all the time? Could it be polution? CO emissions (which there is plenty of) crowding out the bloods O2 stores.

A breathhold in Sweden showed same values as in Bangkok.
90% saturation at 5 minutes and a heartrate of 51.

23 days after coming down from the mountain
92-93% saturation at 5 minutes (based on value at 5.20 due to the "slowness" of the meter). Continuing to 6.30 having a heart arte of 41 and a lowest saturation 86%.
Is this the first signs of a high altitude training effect?
24 days after the mountain
86% saturation at 5 minutes (lowest value). Heartrate 53.
25 days after the mountain
90% and 51 heartrate after 5 minutes
26 days after the mountain
88% and 48 heartrate after 5 minutes

All values from doctors bloodtest 11 days after spending 14 days above 4000 meters.
HB 14,4
HCT 44
WBC 7.300
PMN 68
PlT COUNT 304.000

Lying down (>15 min) reduces HB value with about ten.

Older sealevel values:
Hematokrit HCT: 45% rise to 48% after maxapnea (probably due to spleenrelease).

2) 2006/2007:
Hemoglobinkonc.: 145 g/L (rise to 157 g/L after maxapnea.
Bloodpressure: 107/71 mmHg (resting)

3) 2006
145 before apnea 150 after

3) 2003/2004
HB 155 before breathhold exercises.
HB 165 aftter BH exercises.