Showing posts with label BMI. Show all posts
Showing posts with label BMI. Show all posts

Sep 26, 2014

Overweight Defined

During 1998, twenty nine million Americans suddenly became overweight without gaining an ounce. The US government announced new guidelines lowering the threshold of what classifies a person as overweight.

Previously, if your body mass index (BMI) was less than 28 for men or 27 for women, you were considered 'normal'. Since then only BMIs of 25 or below are considered healthy. That was a reduction of about 20 pounds for the average male. BMI is a ratio of weight to height, and is considered an indicator of how much body fat a person has.

Nov 1, 2013

BMI and Life Expectancy

A comprehensive review published in 2013 in the 'Journal of the American Medical Association' examined the relationship of BMI (Body Mass Index) to death rates. The study researchers found that increasing levels of obesity were associated with progressively higher premature death rates.

Mildly obese people, however, did not have a significantly greater risk of death compared to those with a normal BMI. In fact, the finding that people classified as overweight but not obese had a lower overall death rate compared to those with a normal BMI. Researchers are exploring possible reasons for this finding.

The 'International Journal of Obesity' published a study in 2012 comparing BMI and waist circumference as predictors of life expectancy. The authors reported that waist circumference is a better predictor of death from any cause than BMI. The researchers also found that adults with a high waist circumference had an increased risk of death regardless of BMI. Although neither BMI nor waist size can accurately foretell the life expectancy of any individual, waist circumference may be a better tool for estimating longevity. In other words, they are saying 'we cannot accurately tell life expectancy with either of these measurements, but it does help get us grants and headlines'.

Feb 12, 2013

Sperm Study

Here is another of those studies that makes us wonder who thinks up this stuff. The British Journal of Sports Medicine, looked at the lifestyles of 189 healthy men between the ages of 18 and 22, during a three-month period to establish a link between environmental factors and semen quality. Its finding - men who watch more than 20 hours of television a week risk halving their sperm count.

It said, while regular, vigorous exercise was shown to boost sperm count, excessive television-watching can counteract the positive effects of physical activity and can have a major impact on a man’s ability to reproduce.

Another study by researchers at the University of Sheffield and Manchester compared the lifestyles of 939 men with poor sperm quality with 1,310 men with normal sperm quality. It found “little evidence” that a high BMI, excessive alcohol consumption or recreational drugs were contributing factors to sperm quality. It also found that wearing boxer shorts rather than tighter underwear was linked to higher sperm levels. There was even evidence that high levels of physical activity might have a detrimental effect on quality and quantity.

Dr George Chavarro from the Department of Nutrition at Harvard School at Public Health, senior author of the recent study said, “In general, very little is known about what influences sperm count.”  Too bad for us their fathers didn't watch more TV.