WOMEN FARE BETTER IN SPACE                                                                                      SPACEFLIGHT 51: ,2009

Recently I have published several papers (1-3) ( www.femsinspace.com ) describing various mechanisms to explain why I believe Irwin’s extraordinary stress test – blood pressure ( > 275/125) after just 3 minutes of exercise probably on the day after return from his Apollo 15 mission, was triggered by inhalation of dust in both the lunar habitat for a total of about 40 hours and in the command module during the 3 day journey home.

Furthermore one reason why the cardiovascular recovery of the Apollo 15 crew was” protracted “ for an additional several weeks, may have been because the crew spent an additional 2 days after lunar departure in the command module orbiting the moon, prior to the journey home, in order to continue and complete scientific experiments (4)-- inhaling the dust brought into the habitats with the space suits for 2 days longer than other lunar missions. The cardiovascular mortality rate is 6 times higher in males under age 35; this is related to the female cardiovascular benefits of estrogen, significantly higher levels of magnesium with marginal intakes, and females’ reduced potential for oxidative stress postulated to be secondary to their physiological loss of iron with menstruation. (5,6)

In addition females have 2 more clear cardiovascular advantages as astronauts: First the levels of a peptide ( atrial natriuretic peptide ) in females are approximately twice those of young men (7) whereas with space flight these levels in general have been shown to be reduced by > 40 % on space flights of just 12 days probably because of invariable reductions in plasma volumes.(3) There was no evidence of this peptide’s (ANP) activity i.e. undetectable cGMP after just 5 months during the 438 day mission of Polyakov -- without return to his pre-mission ANP levels until 3 months after space flight. (8).Since ANP is a blood vessel dilator and clot buster, female astronauts would have a considerable space –related cardiovascular advantage and since it is a vessel dilator, females would be less likely to have the degree of hypertension shown in Irwin’s case on Apollo 15. On earth inhalation of dust does not always trigger hypertension and levels to the degree shown in Irwin’s case have not been reported with protection of the vessels because of this peptide.

By the 6th. day after a brief space mission the ANP levels return to pre-mission levels. (3) A second additional advantage is that females have significantly higher levels of a blood vessel growth factor (vascular endothelial growth factor ) than males.(9). This growth factor is required to repair injured blood vessels and to assist in the development of collateral blood vessels – an ongoing process in all of us at any age and necessary for survival. The primary source of this growth factor are platelets which are invariably reduced in the circulation in space. (10)

William J. Rowe M.D. FBIS
1485 Bremerton La.
Keswick, Virginia 22947 U.S.A.


References:
1. W.J. Rowe. Moon dust may simulate vascular hazards of urban pollution. JBIS, 60. Pp133-36, 2007.
2. W.J. Rowe. Moon dust and severe hypertension . Spaceflight. 49, p.276. 2007
3. W.J. Rowe. Extraordinary hypertension after a lunar mission. Amer. J. Med ( in press) 2009.
4. CA Berry. Medical legacy of Apollo. Aerospace Med. 45, pp 1046-57, 1974.
5. W.J. Rowe. The case for an all-female crew to Mars. J of Men’s health and Gender . 1, pp 341-344, 2004.
6. WJ Rowe. Evolution and intelligent design. SPACEFLIGHT , 48. P 156, 2006.
7. BA Clark, D Elahi, FH Epstein. The influence of gender, age, and the menstrual cycle on plasma atrial natriuretic peptide. J Clin Endocrinol Metab 70, pp 349-352, 1990.
8. A Rossler, V Noskov, Z Laszlo, VV Polyakow, HG Hinghoffer-Szalkay. Pemanent depression of plasma c GMP during long-term space flight. Physiol. Res 50, pp 83-90, 2001.
9. A Malamitsi-Puchner , J Tziotis, A Tsonou, E Protonotariou , A Sarandakou, G Creatsas. Changes in serum levels of vascular endothelial growth factor in males and females throughout life. J.Soc Gynecol Investig 7, pp 309-12. 2000
10. E Gunsillius, AL Petzer, G Gasti. Space flight and growth factors. ( letter ) Lancet 353, p 1529. 1999.