We all appreciate the athleticism demonstrated by the elite soccer players competing in the 2014 World Cup in Brazil. Their speed, endurance and skill are remarkable. How fit are these elite athletes? Is fitness something that the rest of us, woefully non-elite, should be concerned about?
Cardiorespiratory fitness is measured by determining how much oxygen the body utilizes during maximal exercise. The measurement of maximal oxygen uptake -- abbreviated VO2 max -- dates back to classic human performance studies conducted in the 1920s by the British physiologist A.V. Hill. VO2 max is a general measure of the ability of the heart to deliver oxygen-rich blood to the working muscles, and the ability of muscles to extract this oxygen to support muscle contraction. Data from the Cooper Institute in Dallas, Texas indicate that the average (50th percentile) VO2 max for men 20-29 years old is 44 milliliters of oxygen for each kilogram of body weight; the average for women in this age group is 37. Values decline with age: Men 40-49 years old have average values of 40 and women, 33. These data are consistent with data from the National Health and Nutrition Examination Survey, a survey of nationally representative persons.
In contrast, elite soccer players have values far higher, with values often above 60 in men, and 50 in women. The Portuguese forward Ronaldo and the Brazilian forward Neymar reportedly have values above 70. VO2 max's above 85 have been reported in a few endurance athletes. Values in this extremely high range require the right genes, as noted by the Swedish physiologist Per Olof Astrand when he said, "if you want to be a world beater [elite performer] then you must choose your parents carefully."
In addition to the right genes, to achieve the VO2 max values of elite soccer players like Ronaldo and Neymar requires a tremendous amount of training. However, regular aerobic training increases VO2 max in nearly everyone. Couch potatoes who simply start becoming active enough to meet physical activity recommendations -- some 150 minutes a week of moderate-intensity physical activity, such as brisk walking -- can expect to increase VO2 max about 5-10 percent.
Unfortunately, there are many Americans of all ages, from children to the elderly, who are profoundly unfit. Low fitness level is an underappreciated yet major public health problem. Simply summarized, being unfit -- that is, having a low VO2 max -- is a risk factor for premature mortality and cardiovascular disease, on par with having high blood pressure, high cholesterol, diabetes, smoking, or being obese. And, in a recent large study of individuals aged 70 to 89 years who had physical limitations, those randomized to 150 minutes a week of physical activity over 2.5 years were 18 percent less likely to have major mobility problems (and thus more likely to maintain independence), compared to those randomized to receiving health education classes.
While it would be nice for everyone to have the VO2 max of an elite World Cup soccer player, from a public health perspective, a more reasonable goal would be to get the least fit among us to simply become moderately fit. The good news is that it doesn't take much exercise and habitual physical activity to change from being unfit to moderately fit. Simply being more active on a daily basis yields considerable health benefits. There has been a gradual shift from highly prescriptive and structured exercise recommendations to a more general "move more" recommendation (example, stairs instead of escalators). Simple step counters can be used to measure daily activity and provide motivation, and reaching 7,000-10,000 steps per day is sufficient to meet current physical activity guidelines.
Fitness level is something we all need to be concerned about. Enjoy the World Cup soccer tournament, but be sure to let the athletic achievements of these highly-fit elite athletes motivate you to move more to increase your VO2 max. Better health will follow.
William B. Farquhar, PhD, is a Professor in the Department of Kinesiology & Applied Physiology, College of Health Sciences, at the University of Delaware. He is a Fellow of the American College of Sports Medicine. Dr. Farquhar studies the role of diet and exercise on human health. Twitter: @farquhar_wbf
I-Min Lee, MBBS, ScD, is a Professor of Medicine, Harvard Medical School and a Professor of Epidemiology in the Harvard School of Public Health. Dr. Lee's main research interest is examining the role of physical activity in promoting health and preventing chronic disease.