full array of health outcomes than to any of the components Dose response curve

Full array of health outcomes than to any of the

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full array of health outcomes than to any of the components Dose-response curve: -First, there is no lower threshold for benefits. Reductions in the risk of mortality appear to begin with the first increase in activity beyond baseline. The belief that a threshold of activity must be achieved before benefits accrue is common but inaccurate - Second, the rate of risk reduction is greatest at the lowest end of the activity scale - Third, in these population-based studies there is no apparent upper threshold where benefits begin to diminish. Although the reduction in risk for each increase in activity is smaller, there appears to be continuous growth in benefits. - Fourth, there is no obvious single volume of activity to choose as a recommended level.
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Accumulation- is the assembling of short episodes of physical activity during a limited period of time (usually one day) to achieve a fuller amount. Duration- is the length of time (usually minutes) an activity is continued. Frequency- is the number of times an activity is performed within a specified time period, usually expressed as bouts, episodes, or sessions per week. Intensity (absolute)- for aerobic activities is the rate of energy expenditure required to perform the activity; it does not consider the physiologic capacity of the person performing the activity. Current practice is to categorize absolute intensity into four categories: sedentary ≤1.5 METs, light intensity 1.6– 2.9 METs, moderate intensity 3.0–5.9 METs, and vigorous intensity ≥6.0 METs (66, 69). Intensity (relative) describes the ease or difficulty with which an activity is performed. It is proportional to one's current maximal capacity. It can also be described by how hard an individual perceives an activity to be: very light, light, moderate, hard, very hard, or maximal. Metabolic equivalent (MET)- is a measure of energy expenditure. One MET is the rate of energy expenditure while sitting at rest, which, for most people, is an oxygen uptake of approximately 3.5 ml/ (kg-min). An advantage to using METs rather than kilocalories or joules to describe energy expenditure is that METs control for body weight. Individuals performing the same activity expend roughly the same number of METs. VO2max, maximal oxygen uptake- is the highest rate at which one can transport and use oxygen during aerobic activities. Except for highly trained athletes, VO2max is lower than it could be. For people who are very inactive, it is substantially lower than it could be. Volume is the total amount of activity accumulated over a specified period of time, usually one week. Volume is commonly expressed in measures of energy expenditure such as kilocalories/week, MET- min/week, minutes/week, or miles/week. -The shape of the dose-response relationship curve likely varies from condition to condition because the physiologic pathways to different health outcomes vary Duration- A wide range of durations appear to provide equivalent benefits as long as daily accumulation and weekly totals are similar Frequency- The benefits of frequencies ≥3 days/week are equivalent if total volume is constant. The
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