Hyperventilation performed before or after exercise induced distinct short-term cardiovascular and muscular responses, with timing influencing autonomic, haemodynamic, and muscle oxygenation outcomes in healthy young men.
Key Findings
Results
Pre-exercise hyperventilation attenuated exercise-induced shifts in heart rate variability spectral power, whereas control and post-exercise hyperventilation conditions showed increased LF and decreased HF power after exercise.
14 healthy physically active men participated (mean age 21.8 ± 0.7 years)
LF power increased and HF power decreased after exercise in the control and post-exercise hyperventilation conditions (p < 0.05)
Pre-exercise hyperventilation attenuated these autonomic shifts
HRV spectra were assessed pre- and post-session at rest
Hyperventilation was performed at approximately 30 breaths·min-1 for 30 seconds before or after each cycling bout
Results
Post-exercise hyperventilation blunted the rise in systolic blood pressure and reduced diastolic blood pressure compared with the control condition.
Differences were statistically significant (p < 0.05)
Arterial blood pressure was measured stage-wise throughout the protocol
The exercise protocol consisted of five 5-minute cycling bouts at 50% of heart-rate reserve with 3-minute passive recovery periods
No structured breathing was used in the control condition
Results
Both pre- and post-exercise hyperventilation accelerated quadriceps muscle oxygen saturation (StO2) recovery compared to control.
StO2 was monitored using near-infrared spectroscopy
Pre-exercise hyperventilation produced higher early recovery StO2
Post-exercise hyperventilation produced sustained StO2 advantages during recovery
Effect sizes were described as moderate-to-extensive for both breathing interventions
Results
The discriminant co-integration index (Dsk) values were consistently highest after exercise, indicating stronger and more coherent multisystem coupling following exercise sessions.
Dsk was calculated to integrate multisystem responses across cardiovascular, autonomic, and muscular measures
Dsk values were consistently highest post-exercise across all three conditions
This pattern was interpreted as reflecting stronger and more coherent multisystem coupling after exercise
Conclusions
The timing of hyperventilation relative to exercise differentially influenced cardiovascular and autonomic recovery responses in healthy young men.
Three conditions were tested in a randomised crossover design: control, pre-exercise hyperventilation, and post-exercise hyperventilation
Pre-exercise hyperventilation attenuated autonomic spectral shifts while producing higher early muscle oxygen recovery
Post-exercise hyperventilation blunted blood pressure rises and produced sustained muscle oxygen saturation advantages
The study was acute in nature and conducted in healthy young men only, limiting generalisability