According to a new study, older women who sit for long periods each day are at increased risk of developing heart disease.
Most scientists and health-care professionals describe sitting as a public health scourge. This is something that most people do at work and in leisure, though.
An earlier study of almost 6,000 people over the age of 18 in the U.S. found that 1 in 4 people sat for more than 8 hours per day.
Published in JAMA and based on data collected by the Centers for Disease Control and Prevention (CDC) in the National Health and Nutrition Examination Survey (NHANES), the study found that just 3 percent of respondents sat less than 4 hours a day and were involved.
Now a new study, published in the Journal of the American Heart Association, has looked at the sitting habits of women with overweight and obesity following menopause. The women were some 55 years old and older.
The researchers analyzed the data as a single group in that observational study. Researchers also split it into two ethnic groups— Hispanic and non-Hispanic — to see if overall sitting time differed by category and how the risk of heart disease was affected.
“Historically, women’s heart disease has been recognized, despite being the number one cause of death for women,” Arizona State University College of Health Solutions ‘ lead author Dr. Dorothy Sears told NccMed.
A third of women will die from heart disease
“One in three women will die from cardiac disease,” Sears said. “Older women are the fastest growing demographic in the United States, and after menopause[ they] experience a significant increase in risk of cardiometabolic diseases such as cardiovascular disease and type 2 diabetes.”
That is why it is critical to understand how habits impact this risk. There is growing evidence which prolonged sitting is not only prevalent but also associated with risk of heart disease and mortality, especially in older adults.
“Postmenopausal women[ with overweight or obesity] who engage in extended sitting probably have a highly elevated risk of cardiometabolic disease,” Sears said.
The study examined 518 women of a mean age 63 and an average body mass index (BMI) with 31 kilograms per square meter (kg / m2). The obesity level is a BMI greater than 30 kg / m2.
The women wore a monitor that monitored their sitting and physical activity for 14 days and underwent a blood test to measure their resistance to insulin and blood sugar.
Exercise does not negate risk
Researchers found that women who were not Hispanic sat on average for more than 9 hours a day, relative to their Hispanic counterparts averaging 8.5 hours a day.
The researchers found connections between prolonged sitting and greater measurements of BMI and waist, as well as increased blood sugar, insulin, triglycerides, and insulin resistance to fasting. All of these are risk factors for heart disease and stroke.
Researchers were shocked by the scope of the results.
“I expected that there would be some association between sitting time and insulin resistance but did not expect such a strong magnitude of effect.”– Dorothy Sears
Researchers found that each additional hour of sitting per day led to an increase in insulin resistance of more than 7 percent, and each additional 15 minutes of uninterrupted sitting saw an average increase of nearly 9 percent in insulin resistance.
Not only that, but the frequency of those interactions shifted very little when researchers monitored the exercise levels of the participants.
“Evidence from our work and that of others suggests that prolonged sitting time is a danger to cardiometabolic health, regardless of exercise,” Sears said.
“In addition to promoting exercise, physicians and other healthcare providers will enable[ people] to minimize their sitting time, total daily sitting time and constant sitting bouts,” she said.
Other studies suggest that replacing sitting time with standing or light exercise in older people can promote health.
“Accumulating evidence suggests that sitting time interruptions should be practiced throughout the day and need not be high intensity or long in duration.”– Dorothy Sears
The study also found that Hispanic women had a more pronounced impact on blood glucose, despite spending less total time sitting a day and for shorter, uninterrupted periods.
The results showed that Hispanic women saw a 5 percent increase in fasting blood sugar levels relative to the other women in the study, who saw only a 1 percent increase for every additional 15 minutes of uninterrupted sitting.
However, Sears said researchers need a more comprehensive multiethnic study to corroborate this result.