Fasting insulin concentration is related to cardiovascular reactivity to exercise in children.
OBJECTIVE
One mechanism through which hyperinsulinemia is linked to hypertension is through its stimulation of sympathetic nervous activity. Thus, insulin concentration may be correlated with indices of sympathetic activity before it is associated with resting blood pressure. We tested this hypothesis by determining the relationship of insulin concentration and sympathetically mediated cardiovascular reactivity to exercise in children.


METHODS
Survey.


METHODS
General community.


METHODS
Volunteer sample of 46 black and white boys and girls, 9 to 11 years of age.


METHODS
None. Fasting insulin concentration was the main independent variable.


METHODS
Systolic blood pressure and heart rate during a standard submaximal bout of treadmill exercise, and systolic blood pressure at peak effort.


RESULTS
The hypothesis was tested by multiple regression analyses controlled for resting values. Insulin contributed significantly to the regression models for submaximal heart rate (P < .001), submaximal systolic blood pressure (P = .001), and peak systolic blood pressure (P = .006).


CONCLUSIONS
Fasting insulin concentration is associated with cardiovascular reactivity to exercise in young children. This supports the hypothesis that the relationship between hyperinsulinemia and hypertension is mediated by sympathetic nervous tone and that the process begins in childhood. Because percent body fat was positively associated with both insulin and cardiovascular reactivity to exercise, prevention of childhood obesity may be a valuable prophylactic measure for these health problems.
D000704:Analysis of Variance; D001823:Body Composition / Q000502:physiology; D002320:Cardiovascular Physiological Phenomena; D002648:Child; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods / Q000706:statistics & numerical data; D005215:Fasting / Q000097:blood* / Q000502:physiology; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood*; D008297:Male; D011863:Radioimmunoassay; D012016:Reference Values; D018709:Statistics, Nonparametric
D007328:Insulin