• Gardner, Andrew (PI)
  • Poehlman, Eric T. (PI)

Project: Research project

Project Details


The older individual constitutes an increasingly large proportion
of the population in the USA. The extremes of fatness or leanness
which are regulated by fluctuations in energy balance are
important health problems in aging man. Regular physical
activity is routinely prescribed for the older individual to aid in
weight control as well as increase the quality of life and
functional independence, yet little is known regarding the effects
of variations in physical activity on food intake and resting energy
metabolism. This proposal will address the effects of fluctuations
in physical activity on 3 outcome variables in old and young men:
1) spontaneous food intake (FI), 2) resting metabolic rate (RMR)
and norepinephrine (NE) kinetics as an indicator of sympathetic
nervous system activity (SNSa). The approach to be taken is as
follows: Study 1 will cross-sectionally examine 4 groups of men
(active and inactive, old and young) to determine the effects of
age and physical activity status on RMR and SNSa in a 10 day
baseline. Study 2A will examine the response of changing physical
activity levels in old and young men with no previous history of
regular physical activity of FI, RMR and SNSa. Volunteers will
participate in a 24 day program of increased physical activity (2
week outpatient, 10 day inpatient) and will be restudied after a 24
day period of resumed inactivity. Adaptations of ACTIVE old and
young men to variations in physical activity may be different than
those of INACTIVE men. Study 2B will therefore examine
changes in FI, RMR and SNSa in old and young men with a history
of regular participation in physical activity and restudied after 24
days of resumed regular physical activity. In experiments 2A and
2B, we will also validate the factorial method with the doubly
labeled water method to estimate total energy expenditure.
These studies will provide new information on how physically
active and inactive lifestyles regulate appetite and resting energy
metabolism in old and young men.
Effective start/end date12/31/897/31/97