February 28 - 29, 2008 Advisory Committee Meeting
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
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