Breathing less to win Paris 2024 gold: A case study using voluntary hypoventilation at low lung volume-based training in a para-badminton athlete

Abstract

Purpose

To examine the feasibility of implementing voluntary hypoventilation at low lung volume (VHL) training during the 2024 Paralympic Games’ preparation of an elite SH6 (short-stature) para-badminton athlete and characterize associated arterial oxygen saturation (SpO₂) and heart rate (HR) responses.

Methods

During a 5-week intervention, 9 VHL-based training sessions were added, consisting of either repeated running-shuttle sprints or badminton-specific exercises performed with maximal end-expiratory breath holding (EEBH). SpO₂ and HR were monitored, rating of perceived exertion (RPE) was recorded, and hypoxic dose was quantified. Within-participant variability and response patterns across training conditions were characterized using visual inspection of the complete time-series data and summary descriptive metrics.

Results

In both training types, a marked decrease in SpO₂ occurred from the first to the last repetition of each set. Mean nadir SpO₂ was higher during repeated running-shuttle sprint sessions vs. badminton-specific exercise sessions (81.8 ± 2% vs. 76.3 ± 3%) due to a shorter EEBH duration (7.2 ± 0.7 s vs. 9.8 ± 0.9 s). Mean session SpO₂, HR, and RPE did not differ between training types, but RPE decreased significantly across sessions, indicating improved tolerance to the VHL-induced hypoxic stimulus.

Conclusions

This case report demonstrates that VHL-based training with maximal EEBH is feasible, well tolerated, and capable of eliciting robust hypoxemic stimuli in an elite SH6 para-badminton athlete.

Introduction

Among the available “Living Low-Training High”-related hypoxic methods, ¹ voluntary hypoventilation at low lung volume (VHL) consists of repeating short periods of exercise with end-expiratory breath holding (EEBH) interspersed with recovery periods in normal breathing. ² Compared with the same exercise performed with unrestricted breathing, this method has been shown to acutely reduce the arterial oxygen saturation (SpO₂) typically to ∼86-88% when EEBH are maintained for a fixed duration (generally 4-6 s). When EEBH are performed up to the breaking point (i.e., for as long as possible), the drop in SpO₂ is more severe (∼73-75%) and is accompanied by a marked hypercapnic stimulus, resulting in substantial blood, and likely intramuscular, acidosis. ³ Following several weeks of high-intensity VHL training, the combined effect of hypoxia and hypercapnia may induce physiological adaptations that enhance anaerobic glycolysis and reduce or delay blood and muscle acidosis.^2,4 These adaptations are paramount for improving performance in sporting discipline involving continuous or intermittent short high-intensity efforts, and are therefore relevant in a wide range of Olympic sports.^5,6 However, its application has never been reported in Paralympic sport.

In Para-badminton, the SH6 category represents para-athletes with reduced stature, altered limb proportions and smaller thoracic dimensions. ⁷ Compared to able-bodied athletes, SH6 para-badminton athletes may exhibit reduced absolute lung volumes, smaller stroke volume, higher breathing frequencies, potentially influencing both respiratory mechanics and cardiovascular function. ⁸ These differential responses may suggest that VHL method, in particular when EEBH are performed up to the breaking point, may result in larger relative arterial oxygen desaturations and amplified cardiovascular strain, as evidenced by greater SpO₂ declines and higher heart rate (HR) responses. It may therefore represent a potent and highly specific stimulus relevant for SH6 para-badminton athletes aiming to maximize physiological adaptations and performance gains.

Because VHL-based training has been overwhelmingly derived from able-bodied populations, with limited transferability to para-athletes, ⁹ the present case report aimed (i) to demonstrate the feasibility and potential relevance of implementing VHL-based training during the final preparation of a SH6 para-badminton athlete competing for the 2024 Paralympic Games and (ii) to descriptively characterize the SpO₂ and HR responses to hypoxic-related VHL stimulus, that may constitute foundational data for future VHL training prescription and adjustments within the Paralympic population.

Case description

Participant

A French male para-badminton athlete (age: 27 y, height: 145 cm, weight: 58 kg, maximal oxygen consumption: 65 mL·min^-1·kg^-1, maximal HR: 197 bpm) competing at elite level (ranked 4^th in 2024) in the SH6 category intentionally requested a specific scientific support for preparing the Paris 2024 Paralympic Games. Training included 16 h of badminton-specific exercises, 2 h of matches, 1 h of mental preparation, and 4 h of strength and conditioning. With his technical staff, he was fully informed of the procedure for scientific support and data collection that complied with the Declaration of Helsinki and was approved by an Ethical Committee (number 2021-483-S92). While assuming the likelihood to be identified, he provided consent form for anonymous dissemination of the data collected.

Training intervention

Before initiating the final preparation for the Paris 2024 Paralympic Games, a familiarization of the VHL method with EEBH maintained up to the breaking point was implemented, with further exploratory work with the technical staff in order to determine the relevant exercises and to adjust the different training parameters (i.e., number of sets, number of repetitions per set, recovery time between sets and repetitions). Then, the VHL-based training intervention was scheduled for the final 5-week preparation period preceding the Paris 2024 Paralympic Games.

This included two VHL-based training sessions per week (48-72 h apart) using either repeated running-shuttle sprints or badminton-specific exercises, except for the third week that included only one badminton-specific session to limit the risk of fatigue development that can occur with extended training cycle (i.e., 5-6 weeks).^5,10

Repeated running-shuttle sprint sessions were carried out on the width of a badminton court (i.e., 6.10 m) and consisted of 3 sets of 8 repetitions followed by 20 s of passive recovery (except for the first week with 25 s of passive recovery) and 2 min of rest between sets, in order to replicate para-badminton competition demand.

Badminton-specific exercise sessions consisted of performing high forehand shots combined with varied sport-specific movements that were carried out either a) on a badminton court, facing the coach and playing shuttlecocks at a rate of ∼0.7 per second; and b) in a reduced space (i.e., player-coach distance of 2.5 m) with shuttlecocks shots at a rate of ∼1.0 per second. Three sets of 12 repetitions with 25 s (1^st week) and 20 s of passive recovery and 2 min of rest between sets, with repetitions increased up to 15 over the following sessions were performed up to the end of intervention (i.e., 4 days before initiating the Paralympic badminton tournament).

Variables measured and statistical analysis

In all trainings, the EEBH duration (corresponding to each repetition duration), SpO₂, HR (both monitored via a pulse oximeter [Nellcor PM10-N, Pleasanton, CA, USA] connected to a forehead sensor placed above the left orbital area [Max-Fast, Nellcor, Pleasanton]) and rating of perceived exertion (RPE; Borg scale 0-10) were measured.

Data are presented as peak/nadir values and means of sets or sessions and complete time-series for each training type. The magnitude of the hypoxic stimulus was determined as the time spent at different levels of SpO₂ (i.e., < 88%, severe hypoxemia; 88% ≤ SpO₂ < 93%, moderate hypoxemia; and 93% ≤ SpO₂ ≤ 95%, mild hypoxemia). ¹¹ Given the n-of-1 design and the limited number of sessions (n = 9), analyses were intentionally restricted to descriptive presentation of physiological responses (i.e., HR, SpO₂), without inferential statistical testing. Accordingly, results are interpreted through visual inspection of the complete time-series data and summary descriptive metrics to characterize within-participant variability and response patterns across training conditions.

Results

Nine VHL-based training sessions were added during the final 5-week preparation period preceding the Paris 2024 Paralympic Games. This corresponds to 303 high-intensity exercise repetitions (96 running-shuttle sprints and 207 badminton-specific movements) with training type-specific responses (Table 1, Figures 1 and 2). In both training types, EEBH duration was always longer in the first than in subsequent repetitions but was shorter during repeated running-shuttle sprints than during badminton-specific exercises (Table 1), corresponding to higher SpO₂ in the first repetition of each set than in subsequent repetitions (Figure 1). Mean SpO₂ per repetition and nadir SpO₂ per set were higher, corresponding to smaller time spent at SpO₂ in severe, moderate and mild hypoxia, but with higher mean HR per repetition and peak HR per set, during repeated running-shuttle sprint sessions than during badminton-specific exercise sessions (Table 1). However, session HR and SpO₂ mean differences did not differ between training types (Figure 2). RPE did also not differ between training types (Table 1, Figure 2), but decreased across sessions (Figure 2).

Table 1.

Mean physiological responses toVHL-based training including either repeated running-shuttle sprints and badminton-specific exercises.

​	Repeated running-shuttle sprints (n = 4)	Badminton-specific exercises (n = 5)
EEBH time (1st repetition) (s)	8.3 ± 0.6	14.2 ± 1.7
EEBH time (2nd to last repetition) (s)	7.2 ± 0.7	9.8 ± 0.9
SpO2 per repetition (%)	85.9 ± 2.0	81.7 ± 3.0
Nadir SpO2 per set (%)	81.8 ± 2.0	76.3 ± 3.0
Time at SpO2 < 88% (s)	57 ± 11	175 ± 34
88% ≤ Time at SpO2 < 93% (s)	82 ± 19	118 ± 23
93% ≤ Time at SpO2 ≤ 95% (s)	50 ± 14	78 ± 16
HR per repetition (bpm)	165 ± 8	153 ± 6
Peak HR per set (bpm)	178 ± 10	166 ± 9
RPE	8.4 ± 0.7	8.0 ± 1.0

EEBH, end-expiratory breath holding; SpO₂, arterial oxygen saturation; HR, heart rate; RPE, rate of perceived exertion; VHL, voluntary hypoventilation at low lung volume. Values are mean ± SD.

Figure 1.

Mean arterial oxygen saturation (SpO₂) for each repetition of each set during the repeated running-shuttle sprint sessions (panel A) and the badminton-specific exercise sessions (panel B) performed using the voluntary hypoventilation at low lung volume method with maximal end-expiratory breath holding. Panels C and D display continuous SpO₂ recordings in each training type.

Figure 2.

Heart rate (HR; panel A), arterial oxygen saturation (SpO₂; panel B) and rating of perceived exertion (RPE; panel C) responses across training sessions (n = 9) using the voluntary hypoventilation at low lung volume method with maximal end-expiratory breath holding. Training included 4 repeated running-shuttle sprint sessions (grey areas; sessions 2, 5, 6 and 8) and 5 badminton-specific exercise sessions (sessions 1, 3, 4, 7 and 9). Values are presented as min-max range with central tendency (mean ± SD).

Discussion

This descriptive case report showcases for the first time the physiological responses of a VHL-based intervention including EEBH of maximal duration in a SH6 para-badminton athlete during his final preparation for the 2024 Paris Paralympic Games. Main findings were that (i) VHL-based exercises elicited consistent and repeatable arterial oxygen desaturations, (ii) the magnitude and temporal pattern of arterial oxygen desaturation differed between running-shuttle sprints and badminton-specific exercises, and (iii) physiological responses stabilized, but with lower RPE, across sessions. From a performance perspective, this VHL-based final preparation led to a gold-medal performance. Although no causal relationship can be established, this may indicate that such VHL-based training was feasible, well tolerated, and compatible with optimal competitive readiness in a SH6 para-badminton athlete.

Consistent with acute responses observed during VHL sessions in previous VHL training studies using the same approach in able-bodied athletes,^5,6 VHL including maximal EEBH elicited marked reductions in SpO₂, with comparable nadir values.^5,6,12 These results confirm a strong VHL-induced acute hypoxemic response, which likely represents a hypoxic stimulus, although SpO₂ returned to near-baseline values during recovery periods, a defining characteristic of VHL-based training. Consequently, this resulted in a moderate cumulative hypoxic dose.

Training type markedly influenced physiological responses. Repeated running-shuttle sprints elicited higher peak and mean HRs, reflecting greater cardiac demand associated with such “all-out” exercise-induced accelerations, braking forces, and rapid changes of direction. However, this was associated with higher nadir and mean SpO₂ and less time spent in hypoxemia than in badminton-specific exercises which induced deeper and more prolonged arterial oxygen desaturation despite lower HR responses, likely due to longer repetition and EEBH duration. This dissociation indicates that VHL-induced hypoxemic stress is not solely driven by external mechanical load.

Bearing in mind that the reduced lung volumes and thoracic dimensions in SH6 para-badminton athletes^7,8 may amplify arterial oxygen desaturation during VHL-based training compared with able-bodied athletes, it is worth mentioning that SpO₂ was consistently higher during the first repetition of each set in both training types and declined in subsequent repetitions. This progressive arterial oxygen desaturation is commonly observed during VHL training^2,3 and likely reflects accumulating physiological strain rather than an increase in external work per se. However, this pattern does not necessarily indicate a progressive increase in metabolic demand as other alternative mechanisms, including incomplete reoxygenation between repetitions, altered ventilation-perfusion dynamics, and cumulative hypoventilation, may also contribute to the observed arterial oxygen desaturation, particularly in this population. The absence of differences in SpO₂ for a given repetition number across sets and sessions suggests rapid physiological stabilization and the ability to reproduce a targeted hypoxic stimulus and hypoxemic response despite session- and cycle-induced accumulated fatigue. The decrease in RPE over the intervention is consistent with a reduced physiological strain for a given training load, which, with similar magnitude of hypoxic stimulus and physiological responses than able-bodied athletes, may support comparable physiological adaptations and performance gains. Interestingly, the present observations are consistent with previous reports showing that therapeutic intermittent hypoxia is generally well tolerated and capable of eliciting reproducible hypoxemic stimuli without persistent cardiorespiratory disturbances in individuals with neurological impairments, including spinal cord injury. ¹³ When combined with sport-specific exercise, the progressive decline in SpO₂ across repetitions, together with preserved recovery between efforts, also aligns with the concept that the physiological effects of intermittent hypoxia depend not only on hypoxemia severity, but also on the duration, number, and temporal pattern of desaturation cycles.^14,15 In this context, the reproducibility of the hypoxic stimulus and its corresponding hypoxemic response across sessions may be relevant, as optimized intermittent hypoxic-hypercapnic synergistic paradigms are thought to maximize adaptive motor- and neuro-plasticity. ¹⁵ Although the mechanisms underlying adaptation to VHL combined with EEBH remain speculative, repeated therapeutic intermittent hypoxic exposure has been associated with improvements in microvascular function through pathways involving reactive oxygen species signaling, nitric oxide bioavailability, and mitochondrial biogenesis, ¹⁶ which may contribute to improved tolerance to repeated intermittent hypoxic exercise.

Practical applications

The findings of this real-world 2024 Paris Paralympic Games preparation highlight that the integration of a structured VHL-based program, including EEBH and combining repeated running-shuttle sprints and badminton-specific exercise can elicit complementary physiological stimuli (i.e., higher cardiac strain through repeated efforts and larger, more prolonged hypoxemia through sport-specific movements). This approach may be particularly valuable during tapering periods, with a meaningful hypoxic conditioning stimulus compatible with technical sharpness and competitive readiness. More largely, these findings support the feasibility of integrating repeated intermittent hypoxic/hypoxemic exposures into sport-specific training in para-athletes, consistent with growing evidence that carefully dosed hypoxia-based interventions can serve as a “plasticity primer” and complement sport-specific exercise paradigms.^13,15

Conclusions

In summary, although no pre-to-post performance was included, this case report provides foundational data demonstrating the feasibility and relevance of the VHL method in para-athletes with short-stature. While documenting the physiological responses in Paralympic competitive gold-winning context does not exclude the multifactorial nature of performance, it addresses a critical gap in Paralympic sports scientific support’s principle that training validated in able-bodied athletes cannot be generalized to para-athlete without empirical evidence.

ORCID iD

Franck Brocherie https://orcid.org/0000-0002-0808-7986