BACKGROUND: Physical activity is well recognized for its role in disease prevention. Public health surveillance and action is warranted to combat the escalating economic and human costs associated with physical inactivity. METHODS: This study examined the proportion of the population who were physically active at intensities, durations and frequencies specified as the minimum to accrue health benefit as per Canada's Physical Activity Guidelines. Data were collected from 769 suburban residents via a telephone survey, and analyzed using three methods: Individual Assessment (IA) where individuals met the required frequency, intensity and duration through a combination of activities; Categorical Assessment (CA) where individuals met the required frequency, intensity and duration in one or more categories leading to duplicated head-counts; and, Time-based Assessment (TA) where individuals met the required time per week (recommended frequency x duration) in a category through some combination of activity. Z-scores were used to test the null hypothesis that the proportion of people meeting the criteria in more than one category was zero. RESULTS: The number of people meeting the guidelines in more than one category (CA) is significantly different (p < 0.01) from zero for adults and the combined population, but not for children. Enough people are meeting the guidelines in more than one category to significantly influence the percentage calculated if one is not careful to avoid counting duplicates. Furthermore, significant differences were found between IA and TA for children, adults and the combined population with the time-based assessment significantly over-predicting the IA results. INTERPRETATION: While 75% of the respondents reported they had been physically active during the previous week, only 39% of respondents reported enough physical activity to meet the guidelines for health benefits. This number varies widely depending on the method of classification. Canadians should be reminded of the physical activity guidelines by their health care providers to insure that those who are active are active frequently enough to accrue health benefit.
BACKGROUND: Physical activity is well recognized for its role in disease prevention. Public health surveillance and action is warranted to combat the escalating economic and human costs associated with physical inactivity. METHODS: This study examined the proportion of the population who were physically active at intensities, durations and frequencies specified as the minimum to accrue health benefit as per Canada's Physical Activity Guidelines. Data were collected from 769 suburban residents via a telephone survey, and analyzed using three methods: Individual Assessment (IA) where individuals met the required frequency, intensity and duration through a combination of activities; Categorical Assessment (CA) where individuals met the required frequency, intensity and duration in one or more categories leading to duplicated head-counts; and, Time-based Assessment (TA) where individuals met the required time per week (recommended frequency x duration) in a category through some combination of activity. Z-scores were used to test the null hypothesis that the proportion of people meeting the criteria in more than one category was zero. RESULTS: The number of people meeting the guidelines in more than one category (CA) is significantly different (p < 0.01) from zero for adults and the combined population, but not for children. Enough people are meeting the guidelines in more than one category to significantly influence the percentage calculated if one is not careful to avoid counting duplicates. Furthermore, significant differences were found between IA and TA for children, adults and the combined population with the time-based assessment significantly over-predicting the IA results. INTERPRETATION: While 75% of the respondents reported they had been physically active during the previous week, only 39% of respondents reported enough physical activity to meet the guidelines for health benefits. This number varies widely depending on the method of classification. Canadians should be reminded of the physical activity guidelines by their health care providers to insure that those who are active are active frequently enough to accrue health benefit.
Authors: Cora L Craig; Alison L Marshall; Michael Sjöström; Adrian E Bauman; Michael L Booth; Barbara E Ainsworth; Michael Pratt; Ulf Ekelund; Agneta Yngve; James F Sallis; Pekka Oja Journal: Med Sci Sports Exerc Date: 2003-08 Impact factor: 5.411