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occurred frequently, we advised to stop the extra water | occurred frequently, we advised to stop the extra water | ||
ingestion and precribed sodium tablets (7.2 g/day) instead. After 2 months he had had no complaints. | ingestion and precribed sodium tablets (7.2 g/day) instead. After 2 months he had had no complaints. | ||
== Discussion == | |||
Our patient had symptoms and signs of exercise-related | |||
(pre)-syncope. Despite extensive investigations we | |||
could not identify a certain cause for this disorder of | |||
cardiovascular regulation. | |||
Our patient had compared to healthy men a low exertional BP<cite>Wolthuis</cite> and compared to healthy endurance | |||
trained men a relatively high resting HR.<cite>Bjornstad</cite> The cardiovascular changes of our patient seem similar to those | |||
seen in patients with postural orthostatic tachycardia | |||
syndrome (POTS) while standing.<cite>Jacob</cite> Supposing that exercise poses a larger workload to the cardiovascular system compared to standing, one could argue that our patient has a mild variant of POTS. | |||
We hypothesized that our patient’s symptoms were | |||
primarily related to failure of sympathetic vasoconstriction. Therefore, we examined the effect of water drinking, as water drinking has been demonstrated to rapidly | |||
raise sympathetic activity.<cite>Jordan</cite> | |||
Water drinking has been described previously by | |||
Shannon et al. as a treatment for orthostatic and postprandial hypotension in patients with autonomic failure | |||
and orthostatic tachycardia in patients with orthostatic | |||
intolerance.Water drinking (480 mL) raises plasma norepinephrine levels as much as classic sympathetic stimuli as caffeine and nicotine.<cite>Jordan</cite> The pressor effect of water in patients and older controls reached a maximum | |||
after 30 minutes and lasted over 60 minutes. In our case | |||
we chose to use 1000 mL tap water instead of 480 mL, as | |||
the pressor effect of 480 mL tap water was not present in | |||
healthy young subjects compared to older controls. | |||
Moreover, as exercise induces a decrease of plasma volume<cite>Holtzhausen</cite> a larger volume is needed. | |||
As the symptoms of post-exercise hypotension result | |||
from an only brief failure of cardiovascular regulation, a | |||
short lasting therapy is preferable. Besides this, symptom relief should outweigh any possible side effect. In | |||
contrast to previously recommended medications,water | |||
drinking has both a short lasting effect and few side effects. Therefore we suggest water drinking as a simple | |||
and possible effective therapy for idiopathic exercise-related syncope. | |||
== References == | == References == | ||