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reciprocal control of the autonomic
branches. Rather, higher level systems
engage in highly sophisticated "banter"
with the autonomic nervous system.

In contrast to the reciprocal
control characteristic of autonomic
reflexes, higher level brain circuits exert
more flexible control over the autonomic
nervous system. This can include the
classic reciprocal control pattern, but can
also include an independent control
pattern in which only the sympathetic
branch or only the parasympathetic
branch of the autonomic nervous system
is activated, and a coactive control
pattern in which both branches are
activated. This greater flexibility in
control may have behavioral and health
significance.

Beliefs about One’s Relationship with
God and Autonomic Functioning

Recently, we used a population-
based sample of 50-68-year-old adults in
the Chicago Health, Aging and Social
Relations Study to examine risk factors
for heart attack, a health outcome known
to be influenced the autonomic nervous
system. We were particularly interested
in whether spirituality influenced risk for
heart attack. With very few exceptions,
everyone in our sample expressed a
belief in God. However, individuals
differed in how they perceived the
quality of their relationship with God,
much as individuals differ in how they
perceive the quality of their relationships
with other people. We defined
spirituality as the degree to which a
personal relationship with God was
believed to offer safety, security,
contentment, and love. One observation
that emerged from this study was that
spirituality was associated with a lower
incidence of heart attack (7). This
remained true after ruling out the effects

of demographics, health behaviors, body
mass index, blood pressure, and other
potential explanatory factors. Short of
divine intervention, was there a rational
explanation for this relationship? We
certainly know that psychological factors
can impact autonomic control, among
other aspects of physiology.

As considered above, when
extreme or prolonged, sympathetic
activation may have harmful
consequences. Heightened sympathetic
activation is known, for example, to
predict a poorer outcome after heart
attack. In contrast, parasympathetic
activity may have beneficial or
protective effects. From the perspective
of a reciprocal model of autonomic
control, high parasympathetic/low
sympathetic control would be optimal
whereas high sympathetic/low
parasympathetic control would be
considered a risk. But we also know that
higher level neurobehavioral systems
may not be constrained to reciprocal
autonomic controls. Moreover, it has
been argued that more autonomic control
is better than little control, in that if
affords greater capacity for adjustment
of visceral functions. Could high levels
of parasympathetic control, for example,
mitigate the negative effects of
sympathetic activation and perhaps yield
an even more advantageous health
outcome?

To examine these questions, we
developed two quantitative measures of
autonomic control (7). The first was a
common metric of autonomic balance
(Cardiac Autonomic Balance), which
represents the relative dominance of the
two branches along a single autonomic
continuum that ranges from purely
parasympathetic control to purely
sympathetic control. This metric is
consistent with the classical model of

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