Evolution and intelligent
design
Spaceflight 48:156, April 2006
Lorna R Michael. First Female To
Complete a
64 Day Staged-Race Across the Entire United States, 2900
miles.
Sir,
If we are to succeed in space-particularly for long missions over six months- I believe we must take advantage of the design required to preserve the species- rather than necessarily preserving the individual.
In order to ensure that the circulation is sufficient, to provide fertilization and implantation of the egg in the uterus, oestrogen levels begin to rise after menstruation and peak just prior to the mid-cycle, at the time of ovulation.
In addition to the advantages of oestrogen in young women to enhance the circulation, likewise magnesium levels are higher in females, because of enhanced uptake, with marginal intakes, in the storage reservoirs in bone and skeletal muscles, with a progressive loss of these reservoirs, beginning in just a few days of space flight.
It has been shown, after Space Shuttle flights, that whereas there is a significant loss of magnesium in males, there is no significant loss in females [1]. Both oestrogen and magnesium are antioxidants and calcium blockers, with the latter protecting the cell from destruction by calcium overload of its energy-producing machinery.
The third clear advantage of young females is their monthly loss of blood, whereas males have no physiological way of losing iron, with an excess of free-iron (not bound to a protein i.e. transferrin), conducive to damage to the lining of the blood vessels, by oxidative stress [2].
Observation of primitive societies, provide a look into the past, by showing, that prior to the crudest of weapons, man probably survived by chasing down animals for up to 2 days, until the animals dropped from exhaustion and then were simply throttled [3].But the increased adrenaline [4] required for these feats of endurance are clearly a distinct disadvantage in space, because the higher adrenaline levels in males, not only increase oxidative stress, with in turn potential injuries to the lining of the blood vessels (endothelium), but they are also conductive to vicious cycles with magnesium reductions, clots, and very rapid heart rates, particularly during space walks (EVA), as well as life-threatening heart rhythm disturbances [5,6].
Many men will attempt to counter these arguments by emphasizing that females simply don’t have the ‘right stuff’. But my experience with extraordinary endurance athletes, beginning over 30 years ago, leads me to different conclusions.
Take
the case of the endurance award-winning female athlete, Lorna Michael, whom
I studied with several non-invasive cardiology tests, as well as magnesium
levels, prior to and following completion of a staged endurance race of 2900
miles across the entire
William J. Rowe
References
1. D.L Harm, R.T Jennings, and J.V. Meek et al, Genome and hormones: gender differences in physiology, Invited review; gender issues related to spaceflight: a NASA perspective, J. Appl. Physiol., 91:pp.2374-2383, 2001.
2. W.J. Rowe, The case for and all-female crew to Mars, J. Men’s Health and Gender (JMHG), 1:pp.341-44, 2004.
3.
R.B. Lee and I. Devore (Eds.), Man the
Hunter,
4. D.L. Eckberg, Bursting into space: alterations of sympathetic control by space travel, Acta Physiol. Scand., 177:pp.299-311, 2003.
5. W.J. Rowe, Interplanetary travel and permanent injury to normal heart, Acta Astronaut., 40: pp.719-722, 1997.
6. W.J. Rowe, Keeping tabs on the heart-beat of space, Spaceflight, 46: p. 126,2004.
7. Michael finishes run across US, Toledo Blade, 22 August 1993.
8. K.E. Friedl, Biomedical research on health and performance of military women: accomplishments of the Defense Women’s Health Research Program (DWHRP), J. Women’s Health, 14, pp.764-802, 2005.