Respiratory Responses during Therapeutic Positioning in Adults with and without Abdominal Obesity

Body positioning is commonly employed in hospitals and intensive care units to enhance respiratory function and minimize complications. While excess abdominal fat is known to affect respiratory mechanics, its impact across various body positions remains unclear.

This study included 52 participants, categorized into normal weight and abdominal obesity groups. Respiratory parameters-including tidal volume (V_T), minute ventilation (V_E), oxygen consumption (VO₂), carbon dioxide production (VCO₂), end-tidal oxygen (PETO₂), end-tidal carbon dioxide (PETCO₂), and metabolic equivalent (MET)-were measured after 40 minutes in five different positions: Fowler's, right lateral, left lateral, supine, and prone. Measurements were obtained using a metabolic stress testing system. A two-way linear mixed-effects model was used to compare outcomes across body positions and participant groups.

Prone positioning resulted in the highest V_T and V_E in both the normal weight (450.6 ± 112.5 ml; 6.9 ± 1.2 l/min) and abdominal obesity groups (630.2 ± 172.9 ml; 9.3 ± 2.4 l/min) (p < 0.01). VO₂ and VCO₂ were also highest in the prone position for both the normal weight (207.8 ± 43.2 ml/min; 196.6 ± 36.8 ml/min) and abdominal obesity groups (264.8 ± 83.3 ml/min; 250.7 ± 75.9 ml/min) (p < 0.01). MET values peaked in the prone position across both groups. VO₂ and VCO₂ were significantly higher in the abdominal obesity group when in the prone position.

The prone position was the most effective in improving ventilation and metabolic responses in both normal weight and abdominal obesity groups, followed by Fowler's. Elevated VO₂ and VCO₂ in individuals with abdominal obesity may reflect increased respiratory and skeletal muscle effort due to excess fat mass.