This past May, scientists and astronauts from around the world converged on the volcanic island of Santorini for the 13th Humans in Space Symposium, organised by the International Academy of Astronautics and the Greek Aerospace Medical Association.

Prominent among the experts present was Dr Joan Vernikos, director of NASA's Life Sciences Division. Recognised worldwide for her research on the effects of zero gravity on human physiology, Vernikos played a pivotal role in landing such an important symposium of the Cycladic island, which was briefly transformed into the centre of gravity for those studying the effects of spaceflight on the human mind and body.

As Director of the Life Sciences Division, Vernikos is in charge of all of NASA's biological and biomedical research activities. These include basic scientific research, developing clinical approaches to protect crews' health, exploring new technologies to support human life in space, and applying the knowledge gained in space to improve life on Earth. It is this latter aspect of the programme that is, as Dr Vernikos says, "a particular passion of mine".

Charting a course for the stars
Born and raised in Alexandria, Egypt, Vernikos received her scientific training in pharmacology, first at the University of Alexandria, and then at the Royal Free Hospital of the University of London. There she earned her Ph.D. studying the hormone and brain mechanisms regulating the body's stress response.

While in London, Vernikos worked with "a fantastic Greek woman", Dr Nora Zaimis, Chair of the Department of Pharmacology and discoverer of the first drugs against hypertension and the first muscle relaxants. Zaimis' excellence as a scientist as well as her elegance and professionalism were a "great influence" on the young
biologist.

From London Vernikos moved the US, where she joined the faculty of the department of pharmacology at the Ohio State University Medical School. When the chairman of the university's Physiology Department was invited to NASA's Ames Research Center in California to head the space agency's first biology organisation, he asked Vernikos to join him. This was in 1964, and she has been at the agency ever since. In 1993, she was appointed head the Life Sciences Division at NASA headquarters in Washinton D.C.

The unbearable lightness of zero
Vernikos' responsibilities include monitoring the health of astronauts before, during and after their spaceflights. By applying special physical therapy regimes, she helps them make the often difficult transition from space back to Earth.

As an expert on stress responses, both bodily and mental, Vernikos made full use of her NASA post in order to explore the response of the human body to what turns out to be one of the most stressful environments of all zero gravity.

Though floating around in the weightlessness of space might sound just like a doctors ideal prescription for our tired Earth-bound bodies, space medicine research has shown that it is actually dangerous to one's health, as the absence of gravity slowly leads body systems to malfunction or deterioration.

The heart, for instance, not having to work to overcome the force of gravity, becomes lazy, its beats becoming fewer and farther between. Because of this, many astronauts faint upon first returning to earth following long space flights. Likewise, bones, which are no longer needed for support, lose calcium ten times faster than they do on Earth, muscles atrophy from disuse, inner ear function where the balance centre is located - is disrupted, red blood cell counts fall. Some of these changes may even be permanent.

Slowing down the ageing process
What struck Vernikos from the very early days of her research at NASA were the similarities between what happens to the body in space and the symptoms of 'normal' ageing. She first observed this in so-called bed rest studies, in which subjects spend time lying down, a position which reduces the influence of gravity on their bodies. Vernikos noticed that the symptoms observed on very healthy bedrest subjects reflected those seen in the elderly, "especially people in nursing homes"

The important conclusion drawn from such an observation was, Vernikos says, that the deterioration associated with age "isn't so much a function of chronological age as of the absence of movement and exercise. Even a minimum of exercise can significantly improve the condition of the body".

Using space data to explore and find ways to mitigate the ageing process has become an important area of research for NASA and Vernikos. She hopes to someday write a book on the results of her research, in order "to help change concepts about ageing, about what is inevitable and what can be avoided".

Though for Vernikos herself - who once started a chocolate truffle business with her husband to prove to herself that she could succeed at something "completely different from my career" - the perils of inactivity will probably never be an issue.