Impacts of Physical Activity, Screen Time, Diet Drinks and Weather on CV Disease

New research on the seasonality of cardiovascular risk factors, physical activity and heart health, children and cardiovascular risk factors, and diet drinks and heart disease in women was presented as part of ACC.14 in Washington, DC.

In one study of 2.8 million adults, researchers at Johns Hopkins looked at seasonal lipid trends and found unfavorable profiles in the colder months compared to warmer months, tracking what is known about patterns in AMI and related mortality. The cross-sectional study categorized the patient samples, taken between 2006 and 2013, by the time of year and compared categories across seasons. Total cholesterol, LDL and non-HDL levels were all higher in the winter than in summer. LDL and non-HDL cholesterol were 4 mg/dL higher in men and 2 mg/dL higher in women during the colder months – a 3.5 percent and 1.7 percent increase, respectively. Triglycerides were 2.5 percent higher in men during the winter.

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"In the summer, we tend to get outside, we are more active and have healthier behaviors overall," said lead investigator Parag Joshi, MD, of Johns Hopkins Hospital.

In terms of physical activity, one study analyzing 25,000 stress tests found that the standard formula for peak exercise heart rate could be flawed because it does not account for gender differences. The formula of "220 minus age" has been used for decades to calculate maximum heartbeats per minute a person can achieve, but the study led by Thomas Allison, MD, of the Mayo Clinic showed significant differences between men and women. Researchers proposed updated formulae to reflect their findings that the age-related decline in peak heart rate is more gradual in women than in men: women ages 40-89 should expect their maximum heart rate to be 200 minus 67 percent of their age; for men, the formula is 216 minus 93 percent of their age.

Another study of physical activity concluded that marathon training improved cardiovascular risk factors among middle-aged, recreational runners who prepared for the Boston Marathon. Jodi L. Zilinski, MD, of Massachusetts General Hospital led the study of 45 male runners, ages 35 to 65, who trained for 18 weeks in advance of the 2013 marathon. Their race preparation led to significant changes in cardiovascular risk: LDL was reduced by five percent overall among participants; total cholesterol fell four percent and triglycerides fell 15 percent. The men collectively showed a four percent increase in peak oxygen consumption.

"Participants experienced cardiac remodeling," Zilinski said. "Even with a relatively healthy population that was not exercise naive."

Looking at children, one of the largest studies to date of outpatient pediatric clinic visits showed that almost one in three kids screened between the ages of 9 and 11 had borderline or high cholesterol. A team led by Thomas Seery, MD, of Texas Children's Hospital examined the records of 12,712 children and found that boys were more likely than girls to have elevated total cholesterol, LDL and triglycerides, while girls had lower HDL. Obese children were more likely to have abnormal lipid profiles than non-obese children.

Another study of pre-teens found that sixth-graders in Michigan who watched the most TV per day were more likely to have cardiovascular risk factors, even when compared to children who spent the same amount time on the computer or playing video games. Analysis of the screen habits of 1,003 children showed that those watching TV two to six hours a day were more likely than the computer/video game group and the low-screen time group to have higher BMI, elevated systolic and diastolic blood pressure, and slower recovery heart rate.

"Our study suggests high TV time in particular is associated with poorer food choices and increased cardiovascular risk," said Elizabeth Jackson, MD MPH, associate professor at the University of Michigan.

Finally, another study led by Ankur Vyas, MD, of the University of Iowa found that postmenopausal women who consumed two or more diet drinks a day were 30 percent more likely to experience a cardiovascular event and 50 percent more likely to die from related cardiovascular disease than women who never, or only rarely, consumed diet drinks. The analysis of 59,614 participants in the Women's Health Initiative Observational Study, who had an average age of 62.8 and no history of cardiovascular disease, saw that after an average follow-up of 8.7 years, the primary cardiovascular outcome occurred in 8.5 percent of the women consuming two or more diet drinks per day compared to 6.9 percent in the five-to-seven drinks per week group; 6.8 percent in the one-to-four drinks per week group; and 7.2 percent in the zero-to-three per month group. The difference persisted when researchers adjusted for other cardiovascular risk factors and co-morbidities. The association between diet drinks and cardiovascular disease warrants further study to define the relationship, Vyas said.

Keywords: Follow-Up Studies, Cross-Sectional Studies, Women's Health, Blood Pressure, Risk Factors, Heart Rate, Cardiovascular Diseases, Obesity, Cholesterol, HDL, Diet, Triglycerides, Exercise Test

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