Did You Know . . .

Space motion sickness (SMS) is experienced by 50 percent or more of astronauts during the first few days of exposure to the microgravity environment of space. Similar to motion sickness on Earth, the symptoms of SMS include loss of appetite, malaise, nausea, vomiting, gastrointestinal disturbances, and fatigue. Importantly, SMS can disrupt the well-being of crew members and impair critical performance during space flight.

SMS has been a perplexing problem in both the Russian and U.S. manned space programs, but although the mechanism is thought to be understood, a solution has not been readily available, at least not in the U.S. When you consider that two Russian cosmonauts hold the record of 366 days in space (half the time required for a Mars voyage), while the U.S. lags greatly behind at 85 days, the question arises: While SMS is usually encountered only during the first few days of space flight, is it possible, nevertheless, that it is involved with any longer-term space ailments?

Some researchers believe that the sustained weightlessness during space flight results in a disturbance of the inner ear, which is the basis of SMS. Studies with jellyfish by Dr. Dorothy Spangenberg, a researcher at the Eastern Virginia Medical School, seem to bear this out.1 Jellyfish are among the simplest organisms possessing a nervous system with structural organs that sense gravity and help maintain balance, much as do the organs of the inner ear in mammals. A mission study of jellyfish seems to confirm the importance of the inner ear for vestibular stability in the weightlessness of space, suggesting that the ill health caused by weightlessness originates in part in the deterioration of the inner ear.

In a recent mission study, the phytonutrient (plant-derived nutrient) vinpocetine was found to inhibit SMS in experimental subjects by inducing vascular relaxation, especially in the inner ear.2 The mechanism responsible for this effect probably involves an enzyme, phosphodiesterase-1, that causes smooth-muscle relaxation in the lining of blood vessels, including the ears' microvessels. The use of vinpocetine for hearing problems, such as tinnitus, also involves relaxation, but of the vestibular system of the cochlear cells within the inner ear, where weightlessness may alter one's sense of balance.

In another study, the gravitational overload that can induce ischemia (impaired blood flow to an organ or tissue) was neutralized by vinpocetine.3 During space flight, ischemic heart-rate disturbances can produce stress-reaction problems with long-range consequences.4 The Soviets have stocked vinpocetine in the medicine cabinet on board the MIR space station. Could the Russians have used vinpocetine to prevent long-term vestibular disturbances, and could this be their secret of flight longevity?5

A recent study of more than 22,000 adults (18 to 64 years) in Finland found that men who reported high levels of satisfaction with their lives were more likely to be alive 20 years later than those who do not.6 Unfortunately, no such association between life satisfaction and longevity was found in women. The abilities of women to cope with distress and dissatisfaction are thought to be better than those of men.

Life satisfaction refers to a sense of general well-being. It was evaluated by measuring interest in life, happiness, loneliness, and general ease of living. Dissatisfaction can cause men to cope with their feelings by abusing alcohol, smoking, and not exercising, while women more often seek friends or professional help for talk or consultation.

Dissatisfied men were more than twice as likely to die of all causes including diseases and accidents than those who were satisfied with life.They were more than three times as likely to die of a disease, the study indicated. Drinking heavily placed men at even higher risk.

Marriage, exercise, high social class, not smoking, and drinking only moderate amounts of alcohol diminished the risks somewhat, but the association between feeling satisfied and living longer remained. Life dissatisfaction may predict mortality and serve as a general health-risk indicator.

A double-blind study has demonstrated convincingly that 5-HTP can enable individuals to achieve a primary elevation of mood that unequivocally produces a state of elation.7 Described as an intense mood elevation with a feeling of well-being, the state produced by serotonin (made from 5-HTP) is one of satisfaction.8 While elation is also related to intoxication, this appears not to be the state produced by 5-HTP. Instead, the use of 5-HTP amplifies feelings of well-being and pleasure.

In the study, three phases were delineated. Phase I (from 0 to 1 hour after uptake of 5-HTP) was characterized by an intense mood elevation, psychomotor activity, and changed perception. Phase II (about 1 to 3 hours after uptake) was characterized by a feeling of well-being and elevated mood, together with a tendency to inactivity and a contemplative mood. Phase III (about 3 to 6 hours after uptake) was characterized by a return to "normality." There were few side effects.

5-HTP may help to alleviate long-term dissatisfaction, suggesting that lifespan can be lengthened by maintaining proper levels of serotonin by using 5-HTP.


  1. Spangenberg DB, Coccaro E, Schwarte R, Lowe B. Touch-plate and statolith formation in graviceptors of ephyrae which developed while weightless in space. Scanning Microsc 1996;10(3):875-87; discussion 887-8.
  2. Hagiwara M, Endo T, Hidaka H. Effects of vinpocetine on cyclic nucleotide metabolism in vascular smooth muscle. Biochem Pharmacol 1984 Feb 1;33(3):453-7.
  3. Gaevyi MD, Adzhienko LM, Makarova LM, Abdulsalam AA. Brain ischemia induced by gravitational overload. Eksp Klin Farmakol 2000 May-Jun;63(3):63-4.
  4. Oraevskii VN, Breus TK, Baevskii RM, Rapoport SI, Petrov VM, Barsukova ZhV, Gurfinkel' IuI, Rogoza AT. Effect of geomagnetic activity on the functional status of the body. Biofizika 1998 Sep-Oct;43(5):819-26.
  5. Matsnev EI, Bodo D. Experimental assessment of selected antimotion drugs. Aviat Space Environ Med 1984 Apr;55(4):281-6.
  6. Koivumaa-Honkanen H, Honkanen R, Viinamaki H, Heikkila K, Kaprio J, Koskenvuo M. Self-reported life satisfaction and 20-year mortality in healthy Finnish adults. Am J Epidemiol 2000 Nov 15;152(10):983-91.
  7. Graw P, Puhringer W, Lacoste V, Gastpar M, Wirz-Justice A. Intravenous L-5-hydroxytryptophan in normal subjects: an interdisciplinary precursor loading study. Part II: profile of psychotropic effects derived from protocols and psychometric investigations. Pharmakopsychiatr Neuropsychopharmakol 1976 Nov;9(6):269-76.
  8. Zawertailo LA, Busto U, Kaplan HL, Sellers EM. Comparative abuse liability of sertraline, alprazolam, and dextroamphetamine in humans. J Clin Psychopharmacol 1995 Apr;15(2):117-24. Published erratum appears in J Clin Psychopharmacol 1995 Jun;15(3):239.

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