Harvard Studies in Brief

The study, published last week, showed that the body clock regulating sleep runs on a cycle about 24 hours and 11 minutes long--not 25 hours as scientists previously thought.

"If the clock had been 25 hours, than it means every day you're going to correct it an hour," said Richard E. Kronauer, a member of the Harvard-MIT division of health sciences and technology and a senior author of the study.

Subjects left their wristwatches at the door and lived for 28 days in an environment of subdued light. Cut off from normal activities such as work and school, study participants lived a 28-hour day as researchers studied their sleep patterns.

By taking measurements of body temperature and the body chemical melatonin, the scientists discovered that exposing the subjects to even dim light during nighttime hours can reset the human clock, making it difficult to wake up on time in the morning.

"The fact that we are that sensitive to light means that people have to be more careful about their daily schedules so they don't screw things up," Kronauer said.

The group studied included adults in their early twenties as well as elderly people. Harvard Medical School professor Dr. Charles A. Czeisler '74, the lead author of the study, said previous studies indicated that many older people suffer from insomnia because the sleep cycle shortens with age.

"There was a lot of evidence that the [sleep cycle] sped up as we got older," Czeisler said. "We now know that that's probably not the case."

The study's findings have major implications for the field of sleep study, scientists said, and will hopefully pave the way for new cures for insomnia.

As for students who cram for a test until the daylight hours, they may find it difficult to get back on track the next morning. Kronauer said since people are most sensitive to light in the evenings, working through the night can wreak havoc with the circadian pacemaker.

"The later you're working, the more you'll feel it," he said.

TV Watching Linked to Adult Diabetes

With school out for summer, many give in to the temptation to catch up with "Jerry Springer" and "Friends." But a recently released study from Harvard University researchers said too much television can be hazardous to your health.

The data, which shows a conclusive link between television watching and risk for adult diabetes, presented last weekend during the American Diabetes Association's annual conference. Researchers found that men who spent 40 hours a week in front of the blue glow were more than twice as likely to to get diabetes than those who watched for less than two hours a week.

"The reason we looked at TV watching and diabetes is because previous studies have found that TV watching is related to weight gain and obesity," said Dr. Frank B. Hu from the School of Public Health, the lead researcher of the study.

Research spanned eight years and followed the exercise and television watching patterns of more than 40,000 men.

"Every two years we sent out a questionnaire to the participants and asked how many hours per week they spent watching television," Hu said.

Hu empasized that the link between television and the disease is likely an indirect one, influenced by other health factors tied to frequent TV viewing.

"We're not implying that TV per se causes diabetes," Hu said. "We believe that the relationship is probably due to weight gain, obesity and sedentary behavior."

Hu said he and the other authors hope to publish the study in the coming months.

"It's an unpredictable process, publication," Hu said. "But it was well received [at the conference] so we hope it will be published."

Action Figures Bulking Up, Says Harvard Study

Barbie may have unattainable curves, but GI Joe's pecs may prove just as demoralizing to the egos of today's preschoolers.

In a recently published study, researchers show how the bodies of action figures have changed through the years. According to the data, toys like GI Joe and Luke Skywalker have gone from naturalistic body types to bulked-up musclemen.

Dr. Harrison G. Pope, associate professor of psychiatry at the Medical School and author of the study, said he is worried that young boys will aspire to the impossibly muscular bodies of their action figures.

"GI Joe has been getting steadily more muscular over the years... by the 70s he had been putting in substantial time at the gym," he continued.

The report reads that the original GI Joe, if scaled to human height, would have a bicep circumference of about 11 1/2 inches--that of an ordinary man.

But a GI Joe Extreme from 1997 would hace biceps that measure 26 inches, larger than any body builder in history.

"We looked at GI Joe and the Star Wars figures the most," Pope said, because both are made by the same manufacturers and both have been steadily popular over time."

Pope was cautious to draw any absolute conclusions about the toys' effect on children.

"We're not saying that playing with these toys make little boys grow up to be neurotic," he said. But Pope added that the bulked-up toys affect society's view of the ideal male body.

"Little kids playing with [the toys] get a very unrealistic idea of the male body image," he said.