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Exercise - Heart Study Casts Doubt on 'Fit But Fat' Theory

2008-05-06T09:22:47-04:00:00

By LINDSEY TANNER, AP Medical Writer

CHICAGO - New research challenges the notion that you can be fat and fit, finding that being active can lower but not eliminate heart risks faced by heavy women. "It doesn't take away the risk entirely. Weight still matters," said Dr. Martha Gulati, a heart specialist at Northwestern Memorial Hospital.

Previous research has gone back and forth on whether exercise or weight has a greater influence on heart disease risks.

The new study involving nearly 39,000 women helps sort out the combined effects of physical activity and body mass on women's chances of developing heart disease, said Gulati, who wasn't involved in the research.

The study by Harvard-affiliated researchers appears in Monday's Archives of Internal Medicine.

Participants were women aged 54 on average who filled out a questionnaire at the study's start detailing their height, weight and amount of weekly physical activity in the past year, including walking, jogging, bicycling and swimming. They were then tracked for about 11 years. Overall 948 women developed heart disease.

Women were considered active if they followed government-recommended guidelines and got at least 30 minutes of moderate activity most days of the week, including brisk walking or jogging. Women who got less exercise than that were considered inactive.

Weight was evaluated by body mass index: A BMI between 25 and 29 is considered overweight, while obese is 30 and higher.

Compared with normal-weight active women, the risk for developing heart disease was 54 percent higher in overweight active women and 87 percent higher in obese active women. By contrast, it was 88 percent higher in overweight inactive women; and 2 1/2 times greater in obese inactive women.

About two in five U.S. women at age 50 will eventually develop heart attacks or other cardiovascular problems. Excess weight can raise those odds in many ways, including by increasing blood pressure and risks for diabetes, and by worsening cholesterol. Exercise counteracts all three.

"It is reassuring to see that physical activity really does make an impact," said lead author Dr. Amy Weinstein of Boston's Beth Israel Deaconess Medical Center. However, she added, "If you're overweight or obese, you can't really get back to that lower risk entirely with just physical activity alone."

University of South Carolina obesity expert Steven Blair, a leading proponent of the "fit and fat" theory, said the study is limited by relying on women's self-reporting their activity levels. That method is not as reliable as a more objective Fitness evaluation including exercise treadmill tests, Blair said. These tests include heart-rate measures to see how the heart responds to and tolerates exercise.

In Blair's research, overweight people deemed 'fit' by treadmill tests did not face increased risks of dying from heart disease.

Dr. Laura Concannon, who specializes in treating overweight patients at Chicago's Advocate Illinois Masonic Medical Center, said the study's message that exercise can help reduce Health risks isn't new, but it's important.

"Anything that can motivate the public is useful because heart disease is becoming a bigger and bigger problem as levels of obesity increase," Concannon said.

Heart Disease Risks Hit Boys in Teens

2008-05-06T09:21:54-04:00:00

Girls protected by hormones during adolescence, study suggests

By Ed Edelson
HealthDay Reporter

MONDAY, April 21 (HealthDay News) -- The first signs that men are at higher risk of heart disease than women appear during the adolescent years, according a new study that tracked boys and girls through their teens.

"This is not what we would have predicted," said Dr. Antoinette Moran, chief of pediatric endocrinology and diabetes at the University of Minnesota Children's Hospital, and lead author of the report in the April 22 issue of Circulation. "Because boys lose fat and gain muscle in adolescence, while girls add body fat."

At the start, 11-year-old boys and girls were similar in body composition, blood pressure and blood levels of lipids (fats). As expected, the percentage of body fat decreased in the boys and increased in the girls over the adolescent years.

Yet the study of the 507 Minneapolis school children found that between the ages of 11 and 19, levels of triglycerides, a type of blood fat associated with cardiovascular disease, increased in the boys and dropped in the girls. Levels of HDL cholesterol, the "good" kind that helps keep arteries clear, went down in boys but rose in girls.

Blood pressure increased in both, but significantly more in boys. And insulin resistance, a marker of cardiovascular risk, which was lower in boys at age 11, rose until the 19-year-old men were more resistant than the women.

But excess weight is of major importance in both sexes, Moran said. "Being overweight or obese can cancel out these relationships and cause increased cardiovascular risk for males and females," she said. "Any protection that the young women had was wiped out by obesity."

A recent study found that more than a third of children and adolescents in the United States are overweight or obese.

The study points toward the importance of hormonal factors in cardiovascular disease risk, Moran explained. "We knew that women had extra protection from cardiovascular disease, and we knew it disappeared after menopause," she said. "This adds further weight to the role of hormones by looking at the other end of the age spectrum."

One possible lesson of the study is that it is never too early to start protective measures against heart disease, said Dr. Stephen R. Daniels, chairman of the department of pediatrics at the University of Colorado.

"Studies have used autopsies of young people who died in accidents to show that by the late teens, the kind of lesions we know cause heart attacks and strokes are in the process of developing," Daniels said. "So, in some ways, our best opportunity to prevent heart disease is to look at children and adolescents and start the preventive process early."

Fighting obesity in the years before adulthood is essential, he said. "Some changes that occur may be due to what is built into the difference between the sexes," he said. "But if you add overweight and obesity, you can increase risk through that mechanism."

More information

Facts about childhood obesity are available from the U.S. Surgeon General.

SOURCES: Antoinette Moran, M.D., chief, pediatric endocrinology and diabetes, University of Minnesota Children's Hospital, Milwaukee; Stephen R. Daniels, M.D., chairman, pediatrics, University of Colorado, Denver; April 22, 2008, Circulation

Obesity and Pregnancy

2008-05-06T09:20:54-04:00:00

(HealthDay News) -- It is well-known that obesity increases the chances of medical complications during pregnancy, but now a new study shows it also puts a financial strain on the Health-care system.

Obese women who are pregnant tend to have longer hospital stays, require more medications, and spend more time with their doctors than normal-weight women do. Much of this is due to complications such as high blood pressure, preeclampsia and Caesarean deliveries, researchers find.

"Right now, about one in five women in the United States who deliver babies are obese," said lead researcher Susan Y. Chu, a senior epidemiologist at the U.S. Centers for Disease Control and Prevention. "Given that there are about 4 million births in the United States each year, that translates to
almost 1 million obese women giving birth."

"Obesity during pregnancy is associated with more use of Health-care services," Chu said. "Even if there is a small increase, it is going to have substantial financial implications."

The report is published in the April 3 edition of the New England Journal of Medicine.

In the study, Chu's team collected data on 13,442 pregnancies that occurred from 2000 to 2004. These births were recorded by a large managed-care system. The researchers looked at the relationship between obesity and the use of Health-care services before and during pregnancy.

Chu's group found that obese women have significantly longer hospital stays compared with normal-weight women. For most obese women, a hospital stay was 4.1 days longer than it was for normal-weight women.

The increased hospital stays were mostly related to more Caesarean deliveries among obese women than normal-weight women, Chu said.

In addition, obese women required more prenatal tests, more ultrasound examinations and more medications than normal-weight women. Obese women also made more phone calls to their doctors and had more physician visits than normal-weight women, the researchers found.

While obese women used more medical services during pregnancy, they were less likely to see nurse practitioners and physicians assistants for prenatal care, Chu's team found.

One expert says that obesity takes both a Health and a financial toll on pregnant women.

"This article accurately reflects the well-known fact that obesity is a significant risk factor in pregnancy," said Dr. Richard Frieder, an obstetrician-gynecologist at Santa Monica-UCLA Medical Center.

"This wasn't a problem 50 years ago, before the fast food/super-size generation that is now having babies," Frieder added.

Complications such as preeclampsia, diabetes, deep vein thrombosis, macrosomia (excessive newborn birth weight), abnormal labor and the need for a Caesarean delivery are the usual reasons for an increased level of care and longer hospital stays, Frieder said.

"This is all just a small example of the massive problem that obesity costs our society, both to individual Health as well as the economic cost to our institutions," Frieder said.

Aerobic Exercise Keeps You Young

2008-04-15T11:17:37-04:00:00

British study found it shaved 10 to 12 years off biological age

WEDNESDAY, April 9 (HealthDay News) -- A person who maintains aerobic Fitness may delay biological aging by up to 12 years, a new analysis shows.

Jogging and other types of aerobic exercise improve the body's oxygen consumption and its use in generating energy (metabolism). However, a steady decline in maximal aerobic power begins in middle age, decreasing about 5 ml/ (kg. min) every decade, according to the information in the analysis.

When maximal aerobic power falls below about 18 ml in men and 15 ml in women, it becomes difficult to do any activity without experiencing major fatigue. A typical 60-year-old sedentary man has a maximal aerobic power of about 25 ml, nearly half of what it was at age 20.

But research shows that a long period of relatively high-intensity aerobic exercise can increase maximal aerobic power by 25 percent (about 6 ml), which equals 10 to 12 biological years.

The analysis was published online in the British Journal of Sports Medicine.

"There seems good evidence that the conservation of maximal oxygen intake increases the likelihood that the healthy elderly person will retain functional independence," said study author Dr. Roy Shephard, of the Faculty of Physical Education and Health and Department of Public Health Sciences, at the University of Toronto in Canada.

Aerobic exercise also reduces the risk of serious disease and promotes faster recovery after injury or illness. Additionally, it helps maintain muscle power, balance and coordination, which reduces the risk of falls.

More information

The U.S. Centers for Disease Control and Prevention has more about healthy aging for older adults.

-- Robert Preidt

SOURCE: BMJ Specialist Journals, news release, April 10, 2008