Understanding our gene limitations            Spaceflight Vol 48 February 2006, 72


(picture of Africa - San (Bushmen), Kalahari, Namibia)

Sir, It has been my experience that most people have difficulty understanding our genetic limitations regarding very prolonged space missions and, more specifically, a mission to Mars of over two years.

 

Even if the problem of possibly an intolerable degree of radiation didn't exist, there are multiple other potential hazards to the body on a Mars mission, which would be quite similar, at times, to those required, for example, with very prolonged endurance running in the heat.

 

If you would ask the average person whether it is possible, to chase an antelope for up to two days until the animal drops from exhaustion, with, in addition, hardly any rest and without a drop of water, and, in addition, with exposure to the intense heat of the desert, almost everyone would come to the conclusion that it is impossible!

 

Yet the Kung bushmen of the Kalahari desert in south central Africa (Botswana) have this capability. This feat has been witnessed repeatedly by an anthropologist from the University of Nebraska, Dr. Robert Hitchcock (personal communication). How can the bushmen accomplish this?

 

Obviously because they have the genetic capability but also, I believe, because they have a rich source of magnesium in their diet--by ingesting about 300 Mongongo nuts a day [1,2]

 

The potential insults to the endothelium (lining of the blood vessels), are similar to those which might occur on a Mars mission [3], precipitated by invariable dehydration with, in turn, elevations of adrenaline and other vessel constrictors, triggering vicious cycles with a potential significant magnesium ion deficit and, in the case of the bushmen, intensified by desert heat [4]. This is conducive to inflammation of the endothelium combined with oxidative stress [5].

 

Why is it, that so many who have never been in space, think that the journey itself to and from Mars would be only a test of one's tolerance to boredom and yet they would insist that the bushmen's feat borders on the impossible? It seems to me that is more than just a problem with their identifying with either group. Our genes probably haven’t changed much in the past 50,000-60,000 years. Looking back will help all of us in looking ahead.

 

William J. Rowe

Virginia, USA

 

 

References

1. W.J. Rowe, Nuts are a rich source of magnesium - for life's sake. Am. J.  Cardiol., 96 (2005) pp.1034-1035.

2. R.B.Lee, What hunters do for a living or how to make out on scarce resources. RB. Lee, I. De Vore, eds, Man the hunter, New York; Aldine De Gruyer 1968,  30-48.

3. W.J. Rowe, Interplanetary travel and permanent injury to normal heart, Acta Astronaut, 40(1997) pp.719-722.

4. G.A Beller, J.T. Maher, LH. Hartley, D.E. Bass, W.E.L. Wacker, Changes in serum and sweat magnesium levels during work in the heat, Aviat. Space Environ. Med. 46, (1975) pp. 709-712.

5. W.J. Rowe, The case for a subcutaneous magnesium product and delivery device for space missions, J Am Coll Nutr, 23, (2004) pp.525S -528S.