Larger thighs associated with lower risk of heart disease in obesity
April 4, 2020
Science Daily/Society for Endocrinology
A larger thigh circumference may be associated with lower blood pressure and a reduced risk of heart disease in people with obesity, according to a study published in Endocrine Connections. In overweight and obese Chinese men and women, larger thigh circumferences were associated with lower blood pressure. These findings suggest that carrying more weight on the thighs may be a marker of better heart health in Chinese obese and overweight people, who are at a greater risk of heart disease. Thigh circumference may be useful for targeting obese and overweight people for earlier detection high blood pressure.
High blood pressure is a major public health problem affecting more than 1 billion people worldwide and is the leading cause of mortality and disability globally. A number of factors can increase risk of high blood pressure, such as being overweight, lack of exercise, smoking, or a high amount of salt in the diet. Elevated blood pressure causes excess strain on the heart and arteries and can lead to build-up of fat in blood vessels, limiting blood flow. This increases the risk of serious health conditions such as heart disease and stroke.
Many people are unaware they have high blood pressure as it rarely has noticeable symptoms. Therefore, identifying high risk individuals early and employing intervention strategies such as monitoring diet or increasing exercise may help prevent further damage to blood vessels and the heart.
Circumference measurements are easy, low cost and previously effective at evaluating risk of certain diseases -- a large waist circumference is well known to be associated with elevated blood pressure and a small thigh circumference is associated with diabetes. However, there are currently no studies that examine the potential of thigh circumference as an indicator of high blood pressure in people with obesity.
Dr Zhen Yang from Shanghai Jiao Tong University School of Medicine investigated the association between thigh circumference and blood pressure in a population of 9,250 Chinese men and women aged 40 or older, of which 5,348 were overweight and obese, and 4,172 were normal weight.
A significant link between larger thigh circumference (more than 55cm in men and 54cm in women) and lower prevalence of high blood pressure was observed consistently in both men and women, independently of age, body mass index, and waist circumference. Whereas those with a small thigh circumference (less than 50cm for women and 51cm for men) were more likely to have elevated blood pressure.
"In contrast to stomach fat, leg fat may be beneficial for metabolism. The most likely cause of this association is that there is more thigh muscle and/or fat deposited under the skin which secretes various beneficial substances that help keep blood pressure in a relatively stable range." Dr Yang explains.
These findings suggest that thigh circumference could potentially be used as a convenient and inexpensive indicator for earlier detection and prevention of high blood pressure and other related complications, such as heart disease, in obese or overweight people. However, due to large differences in thigh circumferences among different races and different physical activity groups, the thigh circumference sizes in this study may not be a reference for other populations.
Dr Yang now plans to further investigate this association by measuring body composition including thigh fat mass, thigh muscle mass, thigh bone mass and thigh proteins. Different proportions of these components may provide clues to the association between thigh circumference and blood pressure and may help us develop future treatments.
https://www.sciencedaily.com/releases/2020/04/200404155609.htm
When it comes to children's ability to think, weight and activity level both matter
October 27, 2015
Science Daily/Medical College of Georgia at Georgia Regents University
Weight and physical activity levels are both factors in a child's ability to acquire and use knowledge, a new study finds. Children who were lean and active scored better on cognitive tests than either their lean, inactive peers or overweight, inactive children, according to the study, which provides some of the first evidence that weight, independent of physical activity, is a factor.
"The question this paper asks that has not been asked before is whether it is just fitness that influences children's cognition," said Dr. Catherine Davis, clinical health psychologist at the Georgia Prevention Institute at the Medical College of Georgia at Georgia Regents University. "What we found is weight and physical activity both matter."
Children who were lean and active scored better on cognitive tests than either their lean, inactive peers or overweight, inactive children, according to the study in the journal Pediatric Exercise Science. The study provides some of the first evidence that weight, independent of physical activity, is a factor.
The study looked at 45 normal-weight children age 7-11, including 24 who were active and 21 who weren't. Children were considered physically active if they participated in organized activities such as swimming, gymnastics, soccer or dance for more than an hour per week. Researchers corroborated this participation with an adult, and children self-reported their physical activity. The study also looked at 45 inactive, overweight children with very similar demographics, with exact matches on gender and race, and close matches on other relevant issues such as parents' marital status and education level and age to help ensure any differences were not strongly linked to socioeconomic status.
As expected, the 24 normal-weight, physically active children had a lower body mass index, or BMI, less fat and a lower resting heart rate than the overweight, inactive children.
When researchers used the well-verified Cognitive Assessment System, the advantages continued to hold. For example, comparing the active, healthy-weight group with the overweight, inactive children, the active group scored nine points higher for planning -- things such as figuring out and carrying out a strategy and using knowledge -- and eight points higher for their ability to pay attention.
Weight as an independent factor among inactive children generated an even bigger difference in the ability to pay attention, with normal-weight inactive children scoring 12 points higher. Those kinds of numbers could be the difference between a child being average in terms of his cognitive function and at the top end of the normal range, Davis said. In fact, the thinner, inactive kids scored higher on attention as well as a summary measure of cognition than their heavier peers.
Still, comparing inactive and active children who were all a healthy weight showed that activity alone clearly provided an edge, with the active children scoring higher in most areas of cognitive function, including 11 points higher for their ability to plan and seven points higher in attention.
"Activity made a difference even among normal-weight kids. That verifies that physical activity makes a difference in brain function," Davis said. The good news is that children, with the help of their families and schools, have time to make healthy lifestyle changes that will modify their weight trajectory, she said.
"These kids are still growing. If they can cut some of the empty calories out of their diet and pick up the pace on physical activity, they may grow into their weight," Davis said.
The long-time investigator of how physical activity affects overweight children was surprised that weight was an independent factor affecting cognition, acknowledging that exactly how and why is unclear. It could be excessive inflammation, hormones, both or neither, Davis said. She noted that while this study focused on weight, it's likely the amount of body fat that actually matters and overweight children in the study consistently had more fat, rather than having a higher weight because of extra muscle mass, for example.
Next steps include studies that also include overweight, active kids to see if heavier children derive as much benefit from physical activity as their normal-weight peers, and to learn more about how weight and physical activity relate to children's brain health.
Both overweight and inactivity have been independently associated with a cognitive disadvantage in children. Davis published a study in 2011 in Health Psychology that showed regular exercise improves the ability of overweight, previously inactive children to think, plan and even do math. Those who participated in 40 minutes of exercise every day after school garnered even more improvement than those who were active for about 20 minutes daily. That study also used the Cognitive Assessment System as well as functional magnetic resonance imaging, which showed those who exercised experienced increased brain activity in the prefrontal cortex -- an area associated with complex thinking, decision-making and correct social behavior. A later study comparing an after-school exercise program to an after-school sedentary program, showed better brain development in the exercise group.
http://www.sciencedaily.com/releases/2015/10/151027123906.htm