(8-18) Many longtime runners are justifiably proud of their trim bodies. After all, we live in an "obesity crisis" era, and thousands of studies have proven the health benefits of a low to modest body weight vs. excess weight. Thin is good.
But "skinny fat" isn't. The subject has been getting a lot of coverage in recent days due to a new study in the British Journal of Nutrition. The research project tracked the BMI and WHR (waist-hip ratio) of more than 5000 Irish residents over age 60. The two measures--BMI and WHR--were then associated with various health risks. WHR is, loosely speaking, a measure of "belly fat" or excess visceral fat around the middle, also termed "central adiposity."
The paper concluded that belly fat was
associated with "poor cognitive performance" to a greater extent than BMI. Since belly fat is mostly fat while BMI includes muscle, this means that more muscle is a good thing.
Bottom line: Keep running to maintain a healthy body weight, but be sure to include strength training in your weekly regimen. Because muscle loss is an inevitable result of aging, older runners in particular need to work harder to maintain their muscle. Cardio fitness alone can't move your legs and arms. You need muscle. (Loss of muscle, or "sarcopenia," is a major problem in the aging population.)
Links to: the British Journal abstract; a short Yahoo News article; and a longer discussion of central adiposity