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Fasting insulin concentration is related to cardiovascular reactivity to exercise in children
1Georgia Prevention Institute, Department of Pediatrics, Medical College of Georgia, Augusta 30912-3710, USA.
Insights
High insulin levels in children are linked to increased cardiovascular responses during exercise, suggesting a connection to hypertension development. This indicates that managing childhood obesity may prevent future cardiovascular issues.
Area of Science:
- Pediatric endocrinology
- Cardiovascular physiology
- Public health
Background:
- Hyperinsulinemia is a proposed mechanism linking hypertension to increased sympathetic nervous activity.
- Insulin concentration may correlate with sympathetic activity before affecting resting blood pressure.
Purpose of the Study:
- To investigate the relationship between insulin concentration and sympathetically mediated cardiovascular reactivity to exercise in children.
- To determine if insulin levels predict cardiovascular responses during physical activity in youth.
Main Methods:
- Cross-sectional survey design involving 46 children aged 9-11 years.
- Fasting insulin concentration was the primary independent variable.
- Cardiovascular reactivity assessed via heart rate and systolic blood pressure during submaximal treadmill exercise.
Main Results:
- Fasting insulin concentration significantly predicted submaximal heart rate (P < .001).
- Insulin levels were significantly associated with 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 hyperinsulinemia-hypertension links are mediated by sympathetic nervous tone, starting in childhood.
- Preventing childhood obesity may be crucial for mitigating these health risks.
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.
Design:
Survey.
Setting:
General community.
Participants:
Volunteer sample of 46 black and white boys and girls, 9 to 11 years of age.
Interventions:
None. Fasting insulin concentration was the main independent variable.
Main Outcome Measures:
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.