Purpose: The aim of this study is to investigate the individuality of airflow shapes during volitional hyperventilation. Methods: Ventilation was recorded on 18 healthy subjects following two protocols: (1) spontaneous breathing (SP₁) followed by a volitional hyperventilation at each subject’s spontaneous (HV_SP) breathing rate, (2) spontaneous breathing (SP₂) followed by hyperventilation at 20/min (HV₂₀). HV_SP and HV₂₀ were performed at the same level of hypocapnia: end tidal CO₂ (F_ETCO₂) was maintained at 1 % below the spontaneous level. At each breath, the tidal volume (V_T), the breath (T_TOT), the inspiratory (T_I) and expiratory durations, the minute ventilation, V_T/T_I, T_I/T_TOT and the airflow shape were quantified by harmonic analysis. Under different conditions of breathing, we test if the airflow profiles of the same individual are more similar than airflow profiles between individuals. Results: Minute ventilation was not significantly different between SP₁ (6.71 ± 1.64 l·min⁻¹) and SP₂ (6.57 ± 1.31 l·min⁻¹) nor between HV_SP (15.88 ± 4.92 l·min⁻¹) and HV₂₀ (15.87 ± 4.16 l·min⁻¹). Similar results were obtained for F_ETCO₂ between SP₁ (5.06 ± 0.54 %) and SP₂ (5.00 ± 0.51 %), and HV_SP (4.07 ± 0.51 %) and HV₂₀ (3.88 ± 0.42 %). Only T_I/T_TOT remained unchanged in all four conditions. Airflow shapes were similar when comparing SP₁-SP₂, HV_SP-HV₂₀, and SP₁-HV_SP but not similar when comparing SP₂-HV₂₀. Conclusions: These results suggest the existence of an individuality of airflow shape during volitional hyperventilation. We conclude that volitional ventilation alike automatic breathing follows inherent properties of the ventilatory system. Registered by Pascale Calabrese on ClinicalTrials.gov, # NCT01881945.