A hunger strike is a time-honored but desperate way for prisoners and political activists to attract attention to their cause.
Of the 166 prisoners being held at the U.S. military detention facility in Guantanamo Bay, Cuba, 84 of them — more than half — are now on a hunger strike to protest their treatment, NPR reports.
And 16 of those prisoners are being restrained and force-fed through tubes inserted into their noses and down to their stomachs, according to Reuters.
To respond to the mass hunger strike, a team of almost 40 medical personnel —including a doctor, nurses and medics — has been flown in to complement the 100 health-care professionals already working in Guantanamo. [10 Ways Terrorist Attacks Rocked America]
But what happens to a hunger striker, and how do doctors and other medical professionals respond?
In 2007, in conjunction with the U.K. Department of Health, the British medical journal The Lancet published guidance on the management of hunger strikers.
People who are in good health at the beginning of a hunger strike "are usually at little risk of dying from malnutrition for at least six to eight weeks," the guidelines state. But people who are ill can die from malnutrition in as little as three weeks.
And if a person also refuses all fluids, including water, "deterioration is very rapid, with death quite possible within seven to 14 days, especially during hotter periods of the year."
Hunger pangs don't last
At the beginning of a fast or hunger strike, hunger pangs usually disappear after two or three days, according to a document on mass hunger strikes from the California Correctional Health Care Services.
After the third day of a hunger strike, the body starts to use muscle protein to make glucose, a sugar that's needed for cell metabolism. Levels of important electrolytes, such as potassium, fall to dangerous levels. The body also loses fat and muscle mass.
After two weeks, people on a hunger strike may have difficulty standing; they can also suffer from severe dizziness, sluggishness, weakness, loss of coordination, low heart rate and a chilled feeling.
Low levels of thiamine (vitamin B1) become a real risk after two or three weeks and can result in severe neurological problems, including cognitive impairment, vision loss and lack of motor skills.
Permanent complications and death
After more than a month of fasting, or when more than 18 percent of body weight is lost, severe and permanent medical complications can occur. It can become very difficult to swallow water, hearing and vision loss can occur, breathing can become labored and organ failure can start to set in.
Beyond 45 days, death is a very real risk, due to cardiovascular collapse or severe infection.
Aside from the physical damage suffered by hunger strikers, psychological changes causing impulsive and aggressive behavior are common. These effects can "enhance the likelihood that [hunger strikers] will starve themselves to death," according to a report from the Journal of Medical Ethics.
Even after a hunger strike ends, refeeding has some real risks, since the metabolic changes that occur during severe fasting can be profound.
According to a 2011 report in the journal Gastroenterology Research and Practice, patients must be carefully managed when reintroducing electrolytes and nutrients after several weeks of fasting.
Hunger strikes and medical ethics
The medical ethics of forced feeding are also a subject of controversy. "The situation at Guantanamo Bay is unique and has been characterized as a 'legal black hole,'" according to a commentary in the Journal of the American Medical Association.
Because "restraints reportedly have been and continue to be used to immobilize competent prisoners … force-feeding at Guantanamo Bay violates the Geneva Conventions, international human rights law and medical ethics," the authors wrote.
Follow us @livescience, Facebook & Google+. Original article on LiveScience.com.
