February 28 — 29, 2008 Advisory Committee Meeting
Subcommittee Report: Functional Health
Miriam Nelson, Ph.D., presented findings in functional health.
Dr. Nelson noted the challenge of interpreting the data due to many different
ways activity is measured. The subcommittee researched the following questions:
In middle-aged and older adults who do not have
moderate/severe functional or role limitations, does regular physical activity
prevent or delay the onset of substantial functional limitations and/or role
There is clear observational evidence that participation in regular activity
is associated with a delay in the onset of moderate to severe functional or
role limitations in middle-aged and older adults. The adults who reported
regular activity at all measurement occasions were at the lowest risk for
functional limitations. Studies that assessed change in physical activity over
time consistently reported that change from lower levels of activity to higher
levels of activity over tie was associated with reduced risk of limitations.
Findings from the observational studies support a dose-response effect. The
strength of the conclusions is limited by issues of confounding with
observational studies. There is limited data on muscle strengthening, balance
and flexibility activities. While there is a dose-response effect, it is
difficult to make a statement about the amount of activity required for
prevention. Finally, no conclusions can be made whether preventive benefits
differ by race or ethnicity.
In older adults, who have functional or role limitations, does
regular physical activity improve or maintain functional ability and role
ability with aging?
Older adults can improve physiologic capacity with targeted exercise at any
age. There is modest evidence that physical activity in older adults with
existing limitations improves functional ability, especially in aerobic and
muscle strengthening exercises. There is limited evidence that physical
activity improves ability. Heterogeneity in the methods used to assess
outcomes made it difficult to compare studies. It is unclear whether single
mode interventions would be as successful as multi-modal interventions. There
is not enough evidence to suggest a dose-response effect or what a threshold
might be to improve function. Finally, the data does not suggest any
differences among the races.
In older adults who are at increased risk for falls and
fall-related injuries and does regular activity reduce the rates of falls and
There is strong evidence that participation in planned physical activity
reduces falls in older adults with the greatest benefits seen in people with
functional deficits. There is limited data that planned activity reduces
injurious falls due to a lack of studies focused on this question. Strength
and balance exercises seem the most beneficial; however there is some
inconsistent data that suggests tai chi can reduce falls in older adults.
There is very little data to support a dose-response effect or to establish a
threshold at which benefits are seen. More studies are needed to focus on how
activity may or may not reduce injurious falls as well as studies on race.