December 27, 2013
Study Highlights Benefits Of Exceeding Physical Activity Recommendations
redOrbit Staff & Wire Reports - Your Universe Online
Individuals who meet or exceed American Heart Association (AHA) recommendations for physical activity are less likely to die prematurely than those who walk less than guidelines suggest, according to new research appearing in the journal PLoS ONE.According to study author Paul T. Williams of the Lawrence Berkeley National Laboratory (Berkeley Lab), there are “substantial health benefits” to exceeding the cardiovascular health organization’s standards, which recommend that adults participate in physical activity at least 2.5 hours per week.
Williams looked at nearly 8,500 men and over 33,500 women who participated in the National Walkers’ Health Study. He calculated their individual energy expenditures in metabolic equivalents (METs), a physiological measurement that calculates the energy cost of physical activity by determining the ratio of metabolic rate during one specific physical activity to a reference metabolic rate. One MET is equal to 3.5 ml O2/kg/min.
Using this measure, Williams divided the study participants into four exercise categories: category 1 (≤1.07 MET-hours/d), category 2 (1.07 to 1.8 MET-hours/d), category 3 (1.8 to 3.6 MET-hours/d), and category 4 (≥3.6 MET-hours/d). Approximately 23 percent of the study participants were in the first category, meaning that they failed to meet the association’s fitness standards, while 16 percent met the guidelines and the remainder exceeded them.
“Over an average of nine and a half years, 2,448 people died - almost 6 percent,” Allison Bond of Reuters Health reported on Wednesday. “Compared to people who didn't meet the guidelines, those who walked more than the basic recommendation had a one-third lower chance of dying during the study period. Those who met but didn't exceed the recommendation had an 11 percent lower chance.”
Those statistics accounted for other potential factors that could influence morality rates, including diet and education levels, Bond noted. Furthermore, the men and women who walked more specifically noticed a reduced risk of dying from a stroke, diabetes and heart disease.
However, despite the established health benefits of walking, Williams explained that the study does not essentially prove that being more active will extend a person’s lifespan. As he told Reuters, “There is always the question of the chicken and the egg – whether people who are healthier are able to walk farther or, conversely, whether the longer distance they walk may translate into better health benefits.”
Based on his findings, however, Williams advocates doubling the minimum amount of physical activity in the AHA guidelines to five hours per week, according to Bond. Furthermore, he suggested developing a two-leveled system which encourages people to increase their activity level – having one tier for people who are primarily sedentary, and a second for those already fairly active.
However, while AHA spokesperson and fitness trainer María Simón agreed that more walking “is obviously better,” she told Reuters that current activity recommendations were appropriate. “The AHA has been very clear in specifying that the recommended guidelines are ‘minimum' requirements to reduce the risk of heart-related diseases and death and has even provided guidelines for increased activity.”