Alteration in heart rate variability in response to rnspiratory pressure loads and pursed lips breathing in healthy subjects

Abstract

Objective: To study the acute effects of low and moderate inspiratory pressure loads and pursed lips breathing maneuver on heart rate variability in healthy young subjects.

Methods: Twenty nine subjects (15 male, mean age: 22.7±0.8 years, IMC: 23.4±0.3 kg/cm²) with normal lung function assessed by spirometry and maximal inspiratory pressure were randomized in three groups and performed the pursed lips breathing (PLB) or breathing against inspiratory pressure loads corresponding to 20% of maximal inspiratory pressure (IL20%) or 50% of maximal inspiratory pressure (IL50%). Heart rate variability (HRV) was assessed in a sited position for a period of 5 minutes before and during intervention.

Results: During PLB we found a significant increases in LF (m/s2) (773±176.3 vs. 4360±1236, p< 0.022) and total power (m/s2) (2302±391.2 vs. 7375±1149, p <0.001). Subjects in the IL20% group had an increase in mean heart rate (78±2.0 vs. 89.2±1.8, p <0,001) and a decrease in total power (m/s2) (5552±1425 vs 2617±594.8 p <0.021). During breathing at IL50% subjects had an increase in LF (m/s2) (1048±252.2 vs. 4586±1327 p <0.026), LF/HF index (2.43±0.55 vs. 6.80±1.80 p <0.009), mean heart rate (78.4±3.3 vs. 87.5±4, bpm, p <0.009) and total power (m/s2) (2504±730 vs. 6976±1678, p< 0.036).

Conclusion: In healthy young subjects pursed lips breathing tends to increase LF values without changes in sympathovagal balance. Breathing at high inspiratory pressure load (IL50%) induces increase and predominance of sympathetic drive and may be seem as a precaution when used in patients with arrhythmias or ectopy.

Financial Support: CNPq