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The chemoreflex: adult versus child comparison
1Human Performance Laboratory, Department of Kinesiology, Harding University, Searcy, AR 72149, USA.
Insights
The muscle chemoreflex impacts heart rate and blood pressure similarly in children and adults. However, blood pressure remains elevated longer in children post-exercise, suggesting a more active arterial chemoreflex.
Area of Science:
- Exercise Physiology
- Cardiovascular Regulation
- Pediatric Physiology
Background:
- The muscle chemoreflex plays a crucial role in cardiovascular adjustments during and after exercise.
- Understanding age-related differences in chemoreflex responses is vital for assessing cardiovascular health in children and adults.
Purpose of the Study:
- To compare the influence of the muscle chemoreflex on heart rate (HR) and blood pressure (BP) responses between children and adults during and after static handgrip exercise with ischemia.
Main Methods:
- Seventy children and 70 adults performed 3 minutes of static handgrip exercise (SHG) at 30% maximal voluntary contraction.
- Muscle ischemia was induced for 4 minutes, followed by 6 minutes of recovery, with continuous HR and BP monitoring.
Main Results:
- Systolic blood pressure (SBP) increased more in adult men versus boys and adult women versus girls during SHG.
- Heart rate (HR) increased similarly in males but more in girls than women during SHG.
- While HR returned to baseline in both groups post-ischemia, blood pressure remained elevated longer in children compared to adults after exercise.
Conclusions:
- The muscle chemoreflex's influence on HR and BP during occlusion is comparable between children and adults.
- Adults exhibit a return of BP to baseline post-exercise, whereas children maintain elevated BP longer.
- This sustained elevation in children's BP may indicate a more active arterial chemoreflex in this age group.
Purpose:
Compare the influence of the chemoreflex on heart rate (HR) and blood pressure (BP) responses between children and adults.
Methods:
Seventy children (35 boys and 35 girls) and 70 adults (35 men and 35 women) performed 30% maximal voluntary contraction static handgrip exercise (SHG) for 3 min, followed by 4 min of muscle ischemia and then 6 min of recovery, while HR and BP were measured.
Results:
During 3 min of SHG, systolic BP (SBP) increased significantly more in men versus boys (23+/-9 vs 18+/-9%) and women versus girls (21+/-10 vs 15+/-7%), respectively. Diastolic BP (DBP) increased similarly during SHG in adults versus children. During SHG, HR increased similarly in males but significantly more in girls versus women (16+/-10 vs 11+/-9%), respectively. During occlusion, HR fell to baseline and remained through recovery in adults and children. Both SBP and DBP decreased similarly during the first minute of occlusion but remained significantly above baseline in adults and children. During the first minute of recovery, BP decreased to baseline in adults. In children, DBP decreased but remained significantly above baseline through recovery. SBP decreased in children during minute 1 of recovery yet remained significantly above baseline for 1-2 min in children.
Conclusions:
The muscle chemoreflex influence on HR and BP is similar in children and adults as evident in the return of HR to baseline, with a similar concomitant maintenance of BP above baseline during occlusion. When occlusion is released, BP returns to baseline in adults, whereas in children DBP remains significantly above baseline through recovery and SBP for 1-2 min. The differing BP response may be explained by a more active arterial chemoreflex in children.
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