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Blood lactate and pyruvate concentrations, and their ratio during exercise in healthy children: developmental
P Pianosi1, L Seargeant, J C Haworth
1Department of Pediatrics and Child Health, University of Manitoba, Canada.
Insights
Children show age-related differences in blood lactate and pyruvate concentrations during exercise. The lactate-to-pyruvate (L:P) ratio increases with age, suggesting developmental changes in energy metabolism.
Area of Science:
- Exercise Physiology
- Pediatric Metabolism
- Biochemistry
Background:
- Blood lactate and pyruvate concentrations, and their ratio (L:P), increase with intense exercise.
- Known differences exist in exercise metabolism between children and adults.
- Age-related variations in pediatric exercise physiology are not fully understood.
Purpose of the Study:
- To investigate age-related differences in blood lactate and pyruvate concentrations and the L:P ratio in children.
- To explore how these metabolic markers change during exercise in different pediatric age groups.
Main Methods:
- Measured whole blood lactate and pyruvate concentrations in 28 healthy children (ages 7-17) at rest and after exercise.
- Exercise protocol involved 6 minutes at two-thirds of maximum work capacity (Wmax).
- Participants were divided into three age groups: <11, 11-14, and 15-17 years.
Main Results:
- Lactate and pyruvate concentrations significantly increased from rest during exercise at two-thirds Wmax (~72% VO2peak).
- Greater increases in lactate concentration were observed with increasing age groups.
- Exercise-induced increases in pyruvate concentration did not differ significantly among age groups.
- The L:P ratio significantly increased with exercise, showing greater increments in older children.
Conclusions:
- Healthy children exhibit an age-dependent rise in blood lactate concentration relative to pyruvate during moderate-intensity exercise.
- The increasing L:P ratio with age suggests developmental changes in lactate production and/or clearance pathways, potentially linked to puberty.
- These findings highlight age-related adaptations in pediatric exercise metabolism.
Abstract:
Blood concentrations of lactate normally increase during and after intense exercise as does the ratio of concentrations of lactate to pyruvate (L:P). Since there appear to be differences in blood lactate concentrations on exercise, in muscle metabolic enzyme activities, and in anaerobic capacity between children and adults, we speculated that there would be age related differences in lactate and pyruvate concentrations, and their ratio among children. Whole blood concentrations of lactate and pyruvate were measured in 28 healthy children aged 7-17 years, split into three age groups: less than 11, 11-14, and 15-17 years. Blood was drawn at rest, immediately after 6 min of exercise at one-third and two-thirds of maximum work capacity (Wmax), and 20 min after completion of work. Lactate and pyruvate concentrations increased significantly from rest to exercise at two-thirds Wmax [approximately 72% of peak oxygen consumption (VO2peak)]. Whereas greater increments in lactate concentration were seen with groups of increasing age, exercise-related increments in pyruvate concentrations were no different among age groups. There was a significant rise in L:P ratio on exercise, with greater increments found from the youngest to the oldest group. There were no sex differences. We concluded that in healthy children exercising at approximately 70% of VO2peak there is a rise in blood lactate concentration in excess of that of pyruvate, such that the L:P ratio rises to a degree determined by age. This suggests age dependent changes, perhaps coincident with puberty, in pathways involved in lactate production and/or elimination.