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Dr. Seals is a Professor in the Department of Kinesiology
and Applied Physiology on the University of Colorado at Boulder
campus, and has an adjunct appointment as Professor in the
Department of Medicine, Divisions of Cardiology and Geriatric
Medicine at the University of Colorado Health Sciences Center
campus in Denver. He received his Ph.D. in exercise/applied
physiology at the University of Wisconsin at Madison, and
performed postdoctoral research training in applied physiology
at Washington University School of Medicine in St. Louis.
Dr. Seals’ primary research interest within the field
of neuroscience is the influence of physiological aging on
autonomic nervous system (ANS) control of the peripheral circulation
and energy metabolism in humans. This research includes the
potential modulatory effects of factors such as habitual exercise,
sodium intake, hormone replacement, and adiposity on aging-ANS
interactions. Some of the key findings of his work in this
area since the early 1990’s include:
- With aging there is an elevation in tonic net whole-body
sympathetic nervous system (SNS) activity due in part to
selective increases in basal SNS activity to skeletal muscle,
the gut, and the heart, whereas SNS activity to the kidneys
and skin are unchanged
- Two mechanisms that appear to contribute to this region-specific
increase in basal SNS activity with age are: 1) an increase
in subcortical brain norepinephrine neuronal activity; and
2) an increase in total and abdominal adiposity, resulting
in an increase in sympatho-excitatory circulating leptin
concentrations
- The chronic elevation in SNS activity with age is associated
with a desensitization of alpha-adrenergic mediated vasoconstriction,
as well as tonic beta-adrenergic stimulation of resting
energy metabolism; despite this, the tonic elevations in
regional SNS activity with age are so great as to produce
a chronic vasoconstrictor state characterized by reduced
blood flow and vascular conductance
- Women demonstrate a markedly lower basal SNS activity
(compared with men), which may contribute to their lower
prevalence of cardiovascular diseases
- In general, SNS activation in response to acute stress
is unchanged with age
- Cardiovagal baroreflex sensitivity declines progressively
with advancing age due in part to a decrease in the compliance
of the elastic arteries in which the baroreceptors are located
- ANS support of arterial blood pressure is altered with
age due to reduced cardiac vagal modulation of cardiac output,
elevated basal SNS, and reduced alpha-adrenergic sensitivity.
Selected Publications:
Jones, PP, Shapiro LF, Keisling G, Jordan J, Shannon JR,
Quaife R, Seals DR. Altered autonomic support of arterial
blood pressure with age in healthy adult men. Circulation
104: 2424-2429, 2001.
Monahan, KD, Tanaka H, Dinenno FA, Seals DR. Central arterial
compliance is associated with age- and habitual exercise-related
differences in cardiovagal baroreflex sensitivity. Circulation
104:1627-1632, 2001.
Bell, C, Seals DR, Monroe MB, Day DS, Shapiro LF, Johnson
DG, Jones PP. Tonic sympathetic support of metabolic rate
is attenuated with age, sedentary lifestyle, and female sex
in healthy adults. Journal of Clinical Endocrinology and Metabolism
86:4440-4444, 2001.
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