June 28 - 29, 2007 Advisory Committee Meeting
Dr. Powell introduced his discussion on adverse events covering four areas:
1) Organizational framework; 2) Risk-benefit approach; 3) Going from inactive to
active and 4) How much is too much?
Adverse events can cover a diverse spectrum such as an elderly woman walking
for exercise and tripping on an uneven sidewalk or an overweight high school
student joining the football team to get in shape and suffering a heat stroke
during practice. An organizational framework needs to be devised to consolidate
these disparate events while at the same time not getting bogged down in too
Thought needs to be given to risk-benefit as there are no benefits with
adverse events. A possible approach is to use indirect evidence; for example, if
inactive individuals have higher death rates than active individuals, an
assumption can be made that the deaths, which would be adverse events from being
active, do not outweigh the benefits, at least in terms of death. Global
assessments could also be used in areas such as functional health, and quality
of life measures enabling us to make some kind of risk-benefit analysis. Another
approach is to look at dose-related injury rates in a few specific activities.
Anther issue is going from inactive to active and it may be a subject that is
very important but we are likely to find relatively little information that
deals with it specifically. Preventive recommendations so far have generally
recommended a minimum level that people are to achieve; however, not much has
been said about how people are supposed to get there, other than maybe unhelpful
advice about seeing a doctor if they're old or sick. It is likely the case that
unaccustomed activity poses the highest risk for many of the adverse events that
we are addressing. It is important that this be addressed properly in order to
make safer recommendations.
Finally, how much is too much? In general, our recommendations have dealt
with what's the minimum level, with some suggestion that if you do a little bit
more, you'll gain a little more benefit. There may be some particular groups or
situations where it becomes clear that doing too much is a risk as well.
Comments from the committee included the following:
The idea that everything with adverse events is bad should not be absolute
and it needs to be put in context relative the alternative.
How much is too much? Reiterate that dose for active people versus
inactive people will be relative. Should address how to recommend getting
inactive people active in a safe manner.
Women with eating disorders should be included in this group.
Over-activity has been known to be one manifestation of eating disorders.
Concern was expressed at how comprehensive this Group might be and should
there be delimitations to the scope. One suggestion included not addressing
the top end of the spectrum – high endurance athletes.
History of adverse events in guidelines was summarized, first from Heart
Association in 1975 as a mechanism promoting prevention of adverse events, not
physical activity. Also later on with move from clinical model to public
health model moving away from intensity as primary recommendation.
It was suggested this group might look at studies that focused on
increasing activity in sedentary people; however, in many instances adverse
events is not reported in detail if at all. An additional suggestion was to
refer to Tim Church's study on older adults.