Alcohol
consumption and high blood pressure
Central effects of alcohol are associated with
activation of the sympathetic nervous system (1). Alcohol increases postganglionar
sympathetic efferences. Compared with earlier investigations on oral alcohol
intake, the alcohol-induced gastric effects and insulin-mediated effects could
be excluded. The study also showed that alcohol has direct peripheral effects
that, after blockade of central mechanisms, lead to a reduced peripheral resistance
and blood pressure during acute administration. The mechanisms underlying
the vasodilating effect of alcohol remain unclear. It is also not known,
why alcohol exhibits a vasodilating effect on the heart, but a vessel-narrowing
effect on the muscle bed of skeletal muscle. The acute vasodilating component
of alcohol is counteracted in the intact organism by the vasoconstriction
arising from sympathetic activation. In treated hypertensive persons,
a moderate consumption of alcohol is associated with a reduced cardiovascular
risk. If one considers that alcohol has a blood pressure-raising effect,
then this potentially protective effect becomes questionable. It should also
be mentioned that calories from alcohol contribute very often to an inadequately
high caloric intake.
1. Randin D, Vollenweider
P, Tappy L, Jequier E, Nicod P, Scherrer U: Suppression of alcohol-induced
hypertension by dexamethasone. N Engl J Med 1995;332:1733-1737