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Published on: April 29, 2013
Blood pressure and heart rate during stress in children born small for gestational age
Kwanchai Pirojsakul1, Apinya Thanapinyo2, Pracha Nuntnarumit2
1Department of Pediatrics, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand. kwanchai.pio@mahidol.ac.th.
Insights
Children born small for gestational age (SGA) exhibit a heightened sympathetic nervous system response to stress, showing greater heart rate increases and longer recovery times compared to healthy peers. This suggests altered stress reactivity in SGA individuals.
Area of Science:
- Pediatrics
- Cardiovascular Physiology
- Endocrinology
Background:
- Sympathetic nervous system (SNS) overactivity is a proposed mechanism for elevated blood pressure (BP) in individuals born small for gestational age (SGA).
- Understanding the cardiovascular and neuroendocrine responses to stress in SGA children is crucial for assessing long-term health risks.
Purpose of the Study:
- To investigate changes in blood pressure (BP) and heart rate (HR) in children born SGA during acute stress.
- To evaluate urinary catecholamine excretion as an indicator of sympathetic activity in SGA children under stress.
Main Methods:
- Nineteen SGA children (6-14 years) and 17 healthy controls underwent a stress test (mathematical task, venipuncture).
- Blood pressure and heart rate were monitored continuously during the stress test.
- Urinary catecholamines (dopamine, epinephrine, norepinephrine) were measured at baseline and post-stress.
Main Results:
- No significant baseline differences in BP or HR between groups; however, SGA children had slightly higher baseline norepinephrine levels.
- SGA children demonstrated significantly greater maximal heart rate increases (31.3% vs. 19.2%) and longer recovery durations (186s vs. 97s) compared to controls.
- A significant inverse correlation was found between birth weight and maximal heart rate increase (r = -0.497, P = 0.003).
Conclusions:
- Children born SGA exhibit an exaggerated heart rate response and prolonged tachycardia during stress exposure compared to healthy controls.
- The inverse correlation between birth weight and heart rate response suggests that lower birth weight is associated with greater sympathetic reactivity.
- These findings indicate heightened sympathetic nervous system responsiveness to stress in children born SGA.
Background:
Increased sympathetic nervous system activity has been proposed as a potential mechanism for the blood pressure (BP) elevation seen in individuals born small for gestational age (SGA). This study was carried out to detect the changes in BP and heart rate (HR) in children born SGA during exposure to stress and to assess for changes in urinary catecholamine excretion.
Methods:
Nineteen children aged 6-14 years born SGA and 17 age- and gender-matched healthy controls were included in the study. The stress test included a mathematical test and venipuncture. BP and HR were monitored during the test. Spot urine samples were collected at baseline and after the stress test to determine dopamine, epinephrine and norepinephrine levels.
Results:
At baseline, there was no difference in BP and HR between the SGA and control groups, but mean urinary norepinephrine levels were slightly higher in the SGA group (55.7 ± 16.1 vs. 43.4 ± 3.8 mcg/gCr; P = 0.10). Compared to the control group, mean maximal HR increase was higher in the SGA group (31.3 ± 3.1 vs. 19.2 ± 3.8%; P = 0.008), and mean duration of maximal HR to baseline HR was longer (186 ± 23 vs. 97 ± 13 s, respectively; P = 0.003). There was a significant negative correlation between birth weight and maximal HR increase (r = -0.497, P = 0.003).
Conclusion:
Children born SGA showed significantly greater increases in HR and significantly longer periods of tachycardia during exposure to stress than did healthy controls. The rise in HR was inversely correlated with birth weight. These findings suggest that children born SGA have a greater increase in sympathetic response when exposed to stress than do healthy individuals.
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