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Research Digest

Dehydration aggravates exercise-induced asthma
If athletes from elite to novice needed yet another reason to drink plenty of fluids during exercise, a new study by UB exercise scientists provides it. Their research shows that dehydration may induce bronchospasm even before exercise and make exercise-induced asthma worse.

"The message continues to be, 'Drink fluids whenever you get the chance,'" said Frank Cerny, associate professor and chair of the Department of Physical Therapy, Exercise and Nutrition Sciences in the School of Health Related Professions. "If you have asthma, dehydration may make it worse, particularly during exercise."

Cerny said exercise-induced asthma probably is caused by heat and water loss from the airways. "By dehydrating yourself, the airways also become dehydrated," he noted.

Asthma is a major health problem in the U.S., with experts placing the incidence among children as high as 40 percent. Cerny said 80-90 percent of asthma sufferers experience exercise-induced bronchospasm, and that about 10 percent of elite athletes have the condition.

In their current study, UB researchers put eight persons between the ages of 19 and 29 with exercise-induced asthma, and eight persons of similar age without the condition, through six minutes of high-intensity exercise on a cycle ergometer and/or treadmill. Each person's forced vital capacity-the volume of air blown out in one second (FEV1 )-was measured before and after exercise, both when fully hydrated and after 24 hours without fluids.

Results showed that among the non-asthmatics, hydration status had no effect on the FEV1 before, during or after exercise. However, the FEV1 of the asthmatics was significantly lower, both before and after exercise, when they were dehydrated, compared to their respiratory performance when completely hydrated.

Researchers found that the rate of respiratory decline remained the same in the asthmatics during exercise, regardless of their state of hydration, but they started out with less capacity when they were dehydrated, Cerny said.

Paula Maxwell, a doctoral student in the Department of Physical Therapy, Exercise and Nutrition Sciences, was the lead researcher on this study.

Dropouts in cardiac rehab are the ones who need it most
Men recovering from a heart attack who are at the highest risk of a second attack-and thus would benefit most from conscientious participation in an exercise program-are the least likely to do so, a UB study has found.

Results of the study showed that heart-attack survivors who were least likely to take part in a prescribed exercise rehabilitation program tended to be overweight, have high cholesterol and triglyceride levels, and smoke tobacco.

"The dropout rate in cardiac rehabilitation is a huge problem," said Joan Dorn, assistant professor of social and preventive medicine in the School of Medicine and Biomedical Sciences and lead author on the study. "We found that the people who were at the most risk were the ones who attended least." The research involved 308 of the 651 participants in the National Exercise and Heart Disease Project (NEHDP), a three-year clinical trial conducted in the U.S. from 1976-79, designed to determine if a structured exercise program could improve long-term survival. John P. Naughton, professor of medicine and former dean of the UB medical school, directed the trial.

Participants in this study, all men between the ages of 30 and 64, randomly were assigned to take part in a structured cardiac-rehabilitation exercise program. This "treatment" group first exercised for eight weeks in a laboratory setting and then began the full rehabilitation program, involving jogging, cycling or swimming at a targeted heart rate three times a week.

Dorn found that men with a higher work capacity, higher peak heart rate, and higher HDL were more likely to stay with the exercise program. They also tended to be older than those who dropped out of the program. Those who stopped exercising were more likely to be overweight, have higher total cholesterol and triglycerides, and a higher depression score. Dorn said the findings may indicate that this program asked too much, too soon.

Study finds no link between male fertility, testicular cancer
A new UB study has shown that the eventual development of testicular cancer appears to have no effect on the ability of these men to father children prior to diagnosis. Scientists had speculated that testicular cancer may be initiated by some event that occurs during the male child's development in the uterus, said lead author Julie Baker, a graduate student in the Department of Social and Preventive Medicine in the School of Medicine and Biomedical Sciences. If that were the case, she said, men who develop the disease later in life could have trouble fathering children in the interim.

In a study comparing fertility patterns in men with testicular cancer and nonhormonal cancers, Baker reported no such relationship. "This should be a bit of comforting news for men in their reproductive years," said Baker. "Not only did we find no relationship between fertility and a subsequent diagnosis of testicular cancer, men with the disease had more children on average prior to diagnosis than controls: 2.3 compared to 1.2."

The study involved 129 men with confirmed testicular cancer who were matched by age to men with cancers of nonhormonal origin-skin, lung, colon, rectal and head/neck-who formed the control group. Participants were seen at Roswell Park Cancer Institute from 1982-98.