Changes in maximal exercise ventilation and breathing pattern in boys during growth: a mixed cross-sectional...

Area of Science:

• Physiology
• Exercise Physiology
• Pediatric Growth

Background:

• Understanding maximal breathing patterns during exercise in adolescents is crucial for assessing respiratory health and athletic potential.
• Pubertal growth significantly impacts physiological parameters, including respiratory function, but its specific influence on maximal breathing patterns during exercise requires further elucidation.
• Previous research has not fully explored how anthropometric characteristics, physical fitness, and respiratory muscle strength interact to shape maximal breathing patterns throughout the entire pubertal period.

Purpose of the Study:

• To characterize changes in maximal breathing patterns during incremental exercise across the pubertal growth period (ages 11-17).
• To determine the contributions of anthropometric characteristics, physical fitness, and respiratory muscle strength to these breathing pattern changes.
• To investigate whether the influence of these factors on maximal breathing patterns differs before, during, and after the pubertal growth spurt.

Main Methods:

• A mixed cross-sectional longitudinal study involving 44 untrained schoolboys aged 11-17, followed for 3 years.
• Measurements included maximal inspiratory and expiratory pressures (PI max, PE max) for respiratory muscle strength.
• During incremental exercise tests to maximal oxygen uptake (VO2max), maximal ventilation (VE max), tidal volume (VT max), breathing frequency (fmax), inspiratory/expiratory times (tI max, tE max), and mean inspiratory flow (VT/tI max) were recorded.

Main Results:

• Significant increases in maximal ventilation (VE max), tidal volume (VT max), and mean inspiratory flow (VT/tI max) were observed with age, while breathing frequency (fmax) and inspiratory/expiratory times (tI max, tE max) remained stable.
• Lean body mass emerged as the primary determinant of VE max, VT max, and VT/tI max, with its influence varying significantly across pre-, during-, and post-pubertal stages.
• Physical fitness was the main determinant of breathing frequency and timing before and after puberty, whereas maximal respiratory muscle strength showed no significant role.

Conclusions:

• Maximal ventilation increases during adolescent growth primarily due to enhanced tidal volume and mean inspiratory flow, not changes in breathing rate or timing.
• Anthropometric characteristics, particularly lean body mass, are key drivers of maximal breathing patterns during exercise in growing boys.
• The relationships between anthropometric factors, physical fitness, and maximal breathing patterns evolve significantly throughout the pubertal growth spurt.