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Physical Activity Guidelines

February 28 — 29, 2008 Advisory Committee Meeting Minutes

General Discussion

Thursday, February 28, 10:05 a.m.

Dr. Haskell opened up general discussion among the committee on the 3 subcommittee reports previously presented.

Discussion started with a question on the cardio-respiratory subcommittee report on what the group considered the most important end points. The report focused in detail on coronary heart disease, cardiovascular heart disease and stroke but only made a general statement suggesting the data is generally consistent with other outcomes. Dr. Kraus responded that this is true; however, with respect to dose, even in the trial literature, there are very few studies that allow one to address issues of just intensity while controlling for volume.

A general question was asked whether there was any data to support the benefits of engaging in activity at lower thresholds rather then the standard 30 minute mark. Dr. Lee responded that there is some data to support this idea but only because there is no data to refute this suggestion due to the way data is being analyzed. The "30 minute" standard has also been institutionally ingrained in many studies. From the cancer perspective it is difficult to determine benefits at this threshold as different cancers have different disease progressions.

Discussion continued on whether any statement of benefit could be made regarding activity at a lower threshold. Many studies cannot support this from a scientific or statistical basis; however, one may interpret a benefit from a clinical perspective. Another challenge in interpreting data is whether one is measuring for total volume or only leisure time activity as some studies only measure for actual time spent on a treadmill, etc.; however, individuals may be engaged in more activity based on their normal every-day routine. A final comment was added regarding the difficulty identifying moderate and vigorous activity if one is not accounting for relative age and fitness levels.

 

 

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