Central and Peripheral Mechanisms of Low Exercise Capacity in Prematurely Born Adults

Area of Science:

• Cardiorespiratory Physiology
• Exercise Science
• Developmental Origins of Health and Disease

Background:

• Premature birth (gestational age < 37 weeks) is linked to diminished exercise capacity.
• The precise physiological mechanisms driving this limitation remain incompletely understood.
• Exertional dyspnea is a common complaint in preterm-born adults, despite normal resting cardiopulmonary function.

Purpose of the Study:

• To investigate the mechanisms of exercise limitation across the oxygen transport chain in adults born preterm.
• To compare exercise performance and cardiopulmonary responses between preterm-born and term-born adults.
• To identify specific factors contributing to reduced exercise capacity in the preterm-born population.

Main Methods:

• A comparative study involving preterm-born (n=10) and term-born (n=8) adults.
• Cardiopulmonary exercise testing including spirometry, submaximal, and incremental cycling protocols.
• Measurement of breath-by-breath gas exchange, heart rate (HR), and cardiac output (Q̇c); calculation of arterial-venous oxygen difference (a-vO₂diff).

Main Results:

• Preterm adults exhibited significantly lower peak power output and oxygen uptake (V̇O₂) compared to term-born adults.
• Cardiac output index (Q̇c index) was lower in preterm individuals at peak exercise.
• A blunted increase in stroke volume index from rest to peak exercise was observed in preterm-born adults.

Conclusions:

• Adults born preterm demonstrate reduced exercise capacity relative to their term-born counterparts.
• Exercise limitation in preterm-born adults is primarily attributed to central cardiovascular mechanisms, specifically impaired stroke volume.
• These findings highlight the long-term impact of premature birth on cardiovascular adaptation to exercise.