This is a subject that has fascinated me ever since I began to have some understanding of the physiological similarities and differences we share with the diving mammals, particularly the Elephant seals. The latest information on their diving behaviour seems to suggest that they are capable of descents close to the depths achieved by the great diving whales.

The Elephant seal has 1 outstanding difference with us –a much higher proportion of myoglobin versus hemoglobin. We have a large proportion of hemoglobin and a comparatively small proportion of myoglobin. The Elephant seal has the reverse a very large proportion of myoglobin.

The myoglobin allows the animal to store O2 in the muscles and recover it on demand. In effect to use the muscles as a kind of oxygen bank that can be drawn on on demand. We of course can not do this. My question to Erika was did she think we could change by specific training the ratios we are born with in favour of more myoglobin to hemoglobin. Interestingly she thought this might be possible.

She mentioned some papers that had studied climbers at altitude, including experiments done on Nepalese Sherpas who escorted Everest expeditions. The papers apparently showed they had developed elevated percentages of myoglobin. This if true could point the way to a huge break through in freediving.