Anatomy and physiology of the autonomic nervous system: Implication on the choice of diagnostic/monitoring tools in 2023.

The autonomic nervous system (ANS) harmoniously regulates all internal organic functions (heart rate, blood pressure, vasomotion, digestive tract motility, endocrinal secretions) and adapts them to the needs. It's the control of so-called vegetative functions, which allows homeostasis but also allostasis of our body. ANS is divided into two systems often understood as antagonistic and complementary: the sympathetic and the parasympathetic systems. However, we currently know of many situations of co-activation of the two systems. Long seen as acting through "reflex" control loops passing through the integration of peripheral information and the efferent response to the peripheral organ, more recent electrophysiological and brain functional imaging knowledge has been able to identify the essential role of the central autonomic network. This element complicates the understanding of the responses of the reflex loops classically used to identify and quantify dysautonomia. Finding the "ANS" tools best suited for the clinician in their daily practice is a challenge that we will attempt to address in this work.

Care through cohort studies: sociological survey of the PROOF cohort study on vascular and cognitive aging.

BACKGROUND: The success of health research depends on the involvement of participants. Few studies have examined the participation of subjects in cohorts. Drawing on a sociological survey on a French cohort around aging, this study proposes to question the nature of interactions between researchers and subjects that would help to understand the motivations of subjects to participate and remain in health research studies. METHODS: Qualitative study combining participant observation within the research laboratory that conducted the cohort and semi-structured interviews with subjects included in the cohort and with members of the research team. RESULTS: This study highlights the existence of two-way care: from the laboratory to the subjects and from the cohort to researchers. Health research seems to correspond to a complex association between subjects concerned with aging and the expected benefits of exceptional monitoring. Research is incorporated into subjects' daily lives, allowing a shift in the purpose of research from overmedicalization to medical safety that subjects experienced as a form of care. CONCLUSIONS: In cohort studies, care is understood as a form of attention to the person through high-quality medical follow-up. Aging is turned into a matter of concern that subjects, in collaboration with researchers, strive to control.

Tyrosinemia type II: Mutation update, 11 novel mutations and description of 5 independent subjects with a novel founder mutation.

BACKGROUND: Tyrosinemia type II, also known as Richner-Hanhart Syndrome, is an extremely rare autosomal recessive disorder, caused by mutations in the gene encoding hepatic cytosolic tyrosine aminotransferase, leading to the accumulation of tyrosine and its metabolites which cause ocular and skin lesions, that may be accompanied by neurological manifestations, mostly intellectual disability. AIMS: To update disease-causing mutations and current clinical knowledge of the disease. MATERIALS AND METHODS: Genetic and clinical information were obtained from a collection of both unreported and previously reported cases. RESULTS: We report 106 families, represented by 143 individuals, carrying a total of 36 genetic variants, 11 of them not previously known to be associated with the disease. Variants include 3 large deletions, 21 non-synonymous and 5 nonsense amino-acid changes, 5 frameshifts and 2 splice variants. We also report 5 patients from Gran Canaria, representing the largest known group of unrelated families sharing the same P406L mutation. CONCLUSIONS: Data analysis did not reveal a genotype-phenotype correlation, but stressed the need of early diagnosis: All patients improved the oculocutaneous lesions after dietary treatment but neurological symptoms prevailed. The discovery of founder mutations in isolated populations, and the benefits of early intervention, should increase diagnostic awareness in newborns.

Long-lasting active lifestyle and successful cognitive aging in a healthy elderly population: The PROOF cohort.

OBJECTIVES: The aim of this study was to determine whether cognitive reserve in the elderly affects the evolution of cognitive performance and what its relationship is with active lifestyles in later life. METHODS: Cognitive performance was evaluated at baseline and 8 years later in 543 participants of the PROOF cohort, initially aged 67 years. Subjects were categorized as Cognitively Elite (CE), Cognitively Normal (CN) or Cognitively Impaired (CI) at each evaluation. At follow-up, demographic data and lifestyle, including social, intellectual and physical behaviors, were collected by questionnaires. RESULTS: As much as 69% (n=375) remained unchanged, while 25.5% (n=138) decreased and 5.5% (n=30) improved. When present, the reduction in cognitive status was most often limited to one level, but was dependent on the initial level, affecting up to 73% of the initially CN, but only 58% of the initially CE. Cognitive stability was significantly associated with the degree of social engagement at follow-up (CE: P=0.009; CN: P=0.025). CONCLUSION: In the healthy elderly, high cognitive ability predicts both cognitive ability and social involvement in later life. Cognitive decline by only one level may also extend the time to reach impairment, underlining the importance of the so-called cognitive reserve.

Sympathetic overactivity due to sleep fragmentation is associated with elevated diurnal systolic blood pressure in healthy elderly subjects: the PROOF-SYNAPSE study.

AIMS: Sleep fragmentation is a landmark of sleep disorders, because microarousals are systematically associated with sympathetic surges (i.e., sympathetic arousals). However, the impact of sympathetic sleep fragmentation on blood pressure (BP) remains understudied. We assessed the relationships between 24 h ambulatory BP monitoring, the autonomic arousal index (AAI) derived from pulse transit time, and heart rate variability indices. We hypothesized that repeated sympathetic arousals during sleep are associated with elevated BP in a large population of elderly volunteers. METHODS AND RESULTS: Volunteer subjects (n = 780, 57.4% women) with a mean age of 68.7 years and free of known sleep-disordered breathing, coronary heart diseases, and neurological disorders underwent polygraphy, 24 h ECG Holter monitoring, and 24 h ambulatory BP monitoring. Multivariate regressions showed that sleep fragmentation, expressed by AAI, was associated with elevated diurnal (P = 0.008) and 24 h (P = 0.005) systolic BP and higher risk for 24 h [odds ratio (OR): 1.70 (1.04-2.80), P = 0.036] systolic hypertension, independently of confounders such as sleep-disordered breathing, body mass index, sex, diabetes, hypercholesterolaemia, and self-reported sleep duration and quality. Increased AAI was associated with higher nocturnal and diurnal low-frequency power (P < 0.001) and low-to-high-frequency ratio (P < 0.001), suggesting nocturnal and diurnal sympathetic overactivity. CONCLUSION: In healthy elderly subjects, repetitive sympathetic arousals during sleep are associated with elevated systolic BP and higher risk of hypertension, after controlling for confounders. Sympathetic overactivity is the proposed underlying mechanism. CLINICAL TRIAL REGISTRATION: NCT00766584 and NCT00759304.

Mechanically activated mesenchymal-derived bone cells drive vessel formation via an extracellular vesicle mediated mechanism.

Blood vessel formation is an important initial step for bone formation during development as well as during remodelling and repair in the adult skeleton. This results in a heavily vascularized tissue where endothelial cells and skeletal cells are constantly in crosstalk to facilitate homeostasis, a process that is mediated by numerous environmental signals, including mechanical loading. Breakdown in this communication can lead to disease and/or poor fracture repair. Therefore, this study aimed to determine the role of mature bone cells in regulating angiogenesis, how this is influenced by a dynamic mechanical environment, and understand the mechanism by which this could occur. Herein, we demonstrate that both osteoblasts and osteocytes coordinate endothelial cell proliferation, migration, and blood vessel formation via a mechanically dependent paracrine mechanism. Moreover, we identified that this process is mediated via the secretion of extracellular vesicles (EVs), as isolated EVs from mechanically stimulated bone cells elicited the same response as seen with the full secretome, while the EV-depleted secretome did not elicit any effect. Despite mechanically activated bone cell-derived EVs (MA-EVs) driving a similar response to VEGF treatment, MA-EVs contain minimal quantities of this angiogenic factor. Lastly, a miRNA screen identified mechanoresponsive miRNAs packaged within MA-EVs which are linked with angiogenesis. Taken together, this study has highlighted an important mechanism in osteogenic-angiogenic coupling in bone and has identified the mechanically activated bone cell-derived EVs as a therapeutic to promote angiogenesis and potentially bone repair.

The physical activity experience of prostate cancer patients: a multicentre peer motivation monitoring feasibility study. The Acti-Pair study.

BACKGROUND: Although the benefits of physical activity (PA) on health are recognised, prostate cancer patients do not follow PA recommendations. The barriers to PA, whether physical, environmental or organisational, are known. Furthermore, even when such barriers are overcome, this achievement is not systematically accompanied by a change in lifestyle habits. The proposal of a programme enabling the integration of PA in the patient's everyday life represents a new challenge in the personalized management of cancer patients. Peer-mentoring interventions have demonstrated their effectiveness in increasing adherence to PA by patients. This study aimed (1) to assess the feasibility of a peer-mentoring intervention: the Acti-Pair program in a local context and (2) to assess the effectiveness of the intervention in this context. METHODS AND ANALYSIS: A pre-post  design pilot study will be used to evaluate feasibility, potential effectiveness and implementation outcomes overs in prostate cancer patients. We performed a mixed quantitative and qualitative prospective study to assess means and process indicators and the implementation of the Acti-Pair program. This study will be performed in cancer centres of Loire district and will be comprised of three successive stages (1) diagnosis of the target population, (2) recruitment and training of peers, and (3) implementation of this intervention in the Loire department. DISCUSSION: This study will allow us to extend the peer-mentoring intervention to other contexts and assess the effectiveness of this intervention and its generalisability.

Sex differences in obstructive sleep apnoea in an elderly French population.

Obstructive sleep apnoea (OSA) affects females and males differently, and increases in prevalence with age. The aim of the present study was to characterise clinical, anthropometric and polygraphic sex differences in a large elderly OSA population. A total of 641 subjects aged 68 yrs were examined. Measurements of fat mass, using dual-energy X-ray absorptiometry (DEXA) and polygraphy, were obtained in all subjects. An apnoea/hypopnoea index (AHI) of >15 events·h⁻¹ identified the presence of OSA. OSA was diagnosed in 57% of the sample, 34% having a mild form and 23% having an AHI of >30 events·h⁻¹. Females with OSA exhibited a lower AHI, less severe hypoxaemia and greater peripheral fat mass, and frequently reported anxiety and depression. Comparison of females with and without OSA did not reveal significant differences in clinical, anthropometric and DEXA data. After adjustment for body mass index, hypertension, diabetes, smoking, anxiety and depression, logistic regression analysis revealed that the presence of hypertension was significantly associated with OSA risk in females (OR 1.52, p = 0.04). In a general community healthy population, the prevalence of undiagnosed OSA in females increases with age, with a risk similar to that in males. In females, the clinical spectrum, anthropometric data and fat distribution appear to be more sex-related than OSA-dependent. The occurrence of OSA contributes to hypertensive risk in elderly females.

Oral health status and cardiovascular risk profile in Cameroonian military population.

BACKGROUND: Periodontal diseases (PD) seem to appear today as predictors of some cardiovascular diseases (CVD). There is a lack of data on the oral health among Cameroonian military population, and its relationship with CVD. PURPOSE: Investigate on the link between oral health of Cameroonian military from the Ngaoundéré garrison and their cardiovascular risk profile. PARTICIPANTS AND METHODS: A cross-sectional study at the Fifth Military Sector Health Center in Ngaoundéré was conducted. General health parameters assessment was done according to the World Health Organization STEPS manual for surveillance of risk factors for non-communicable chronic diseases and the Alcohol Use Disorders Identification Test. The periodontal status was assessed using Dutch Periodontal Screening Index. RESULTS: Two hundred and five participants who were officers and non-commissioned officers (aged 47 ± 08 and 32 ± 08 years respectively), with 86.4% of men were included. Smoking was associated to periodontitis (OR = 4.44 [1.73-11.43], p = 0.0031). Quality of oral hygiene was associated to high cardiovascular risk profile, poor/good (OR = 3.96 [1.07-14.57], p = 0.0386) and medium/good (OR = 3.44 [1.11-10.66], p = 0.0322). CONCLUSION: Lifestyle as tobacco consumption and poor oral hygiene were associated to CVD among military, and this call for change.

Is tidal expiratory flow limitation predictive of sleep-related disorders in the elderly?

Sleep-related disorders represent an important health burden and their prevalence increases with age. In patients with snoring or sleepiness, the presence of expiratory flow limitation (EFL), determined via the negative expiratory pressure (NEP) method, is related to the apnoea/hypopnoea index (AHI). In this study, we examined whether EFL can be used to predict obstructive sleep apnoea syndrome (OSAS) in healthy asymptomatic older subjects. A group of 72-yr-old subjects (n = 448, 44% males) with a mean body mass index of 25.5±3.8 kg·m(-2) were examined. All subjects underwent spirometry, NEP (-5 cmH(2)O, sitting position) and ventilatory polygraphy (VP). Spirometry was within normal values in 88% of the group and EFL was present in 143 (32%) subjects with a higher prevalence in females (89 out of 249 versus 54 out of 199 in females and males, respectively). VP showed an AHI<15 h(-1) in 238 subjects (53%) and OSAS with an AHI ≥15 h(-1) in 47%. EFL was found in 15% of subjects with OSAS. Consequently, EFL had low sensitivity and specificity in the prediction of OSAS (31.4% and 67.7%, respectively). We conclude that the prevalence of EFL is elevated in healthy older subjects and cannot be used to predict the presence of sleep-related disorders in an older population.

Semliki Forest virus-mediated gene therapy of the RG2 rat glioma.

AIMS: Glioblastoma multiforme is the most common and most malignant adult brain tumour. Despite numerous advances in cancer therapy there has been little change in the prognosis of glioblastoma multiforme, which remains invariably fatal. We examined the Semliki Forest virus virus-like particle (SFV VLP) expression system encoding interleukin-12 (IL-12) as a therapeutic intervention against the syngeneic RG2 rat glioma model. METHODS: Glioma-bearing rats were treated with IL-12-encoding SFV VLPs via an implanted cannula. Animals were treated with 5 × 107 (low-dose) or 5 × 108 (high-dose) VLPs per treatment and the effect on glioma growth and survival was assessed. RESULTS: Low-dose treatment produced a 70% reduction in tumour volume, associated with a significant extension (20.45%) in survival that was dependent upon IL-12 expression. High-dose treatment resulted in an 87% reduction in tumour volume, related to the oncolytic capacity of the SFV VLP system. VLP delivery to the central nervous system (CNS) demonstrated the potential of the vector system to induce lethal pathology that was unrelated to replication-competent virus or high-level IL-12 expression. Treatment-related death was pronounced in high dose-treated animals and appeared to be the result of inflammation, necrosis and oedema at the inoculation site. CONCLUSION: The efficacy of an IL-12 gene therapy approach for the treatment of the RG2 glioma model has been demonstrated in addition to the oncolytic capacity of the VLP vector system. Despite this, the broad tropism of the SFV-based expression vector may limit use as a CNS gene therapy vector unless this inherent limitation can be overcome.

Decrease in gait variability while counting backward: a marker of "magnet effect"?

Counting backward (CB) and walking are both rhythmic tasks. An improvement of CB performance has been reported while walking, and has been interpreted as a "magnet effect" which is the tendency of biological oscillators to attract each other. The objective of this study was to compare the coefficient of variation (CoV) of stride time (ST) and the number of enumerated figures while single- and dual-tasking between older adults who increased and decreased their CoV of ST while CB. The number of enumerated figures and the CoV of ST under single-task (i.e., CB while sitting or walking alone) and dual-task (i.e., CB while walking) were measured among 100 community-dwelling older subjects (mean, 69.8 ± 0.07 years). Subjects were separated into two groups according to the dual-task-related changes in CoV of ST (i.e., either above or below the mean value of CoV of ST under single-task). Seventeen participants decreased their CoV of ST while CB compared to usual walking (2.6 ± 1.6% vs. 2.0 ± 1.3%, P < 0.001), while 83 increased their CoV of ST (1.7 ± 0.6% vs 3.4 ± 2.3%, P < 0.001). The subjects who decreased their CoV of ST had a tendency to enumerate more figures while walking compared to sitting (20.9 ± 6.3 vs 19.4 ± 4.7, P = 0.046) unlike those who increased their CoV of ST (20.3 ± 5.0 vs 21.8 ± 6.0 while sitting, P = 0.001). We found that most of subjects had worse gait and CB performance while dual-tasking. Conversely, a limited number of subjects improved significantly their gait performance and simultaneously had a tendency to improve their CB performance while walking compared to sitting. This behavior was observed only among subjects with the highest gait variability and could be interpreted as an implicit strategy based on the "magnet effect".

Association between C-reactive protein and unrecognised sleep-disordered breathing in the elderly.

Elevated levels of C-reactive protein (CRP) have been reported in patients with sleep-disordered breathing (SDB) and may represent an inflammatory marker of cardiovascular risk. However, the association of CRP with SBD in presumed healthy elderly subjects is unknown. In total, 851 (58.5% females) 68-yr-old subjects, who were free of any known cardiac or sleep disorders, were prospectively examined. Subjects underwent unattended polygraphy, and the apnoea/hypopnoea index (AHI) and oxyhaemoglobin desaturation index (ODI) were assessed. Elevated levels of CRP were found on the morning after the sleep study in patients with more severe SDB. A significant correlation was found between CRP levels, time spent at night with arterial oxygen saturation <90% and ODI. No association was found between CRP levels and AHI. After adjustments for body mass index, smoking status, hypertension, diabetes and dyslipidaemia, a significant association remained between CRP levels and ODI >10 events.h(-1). CRP levels were frequently increased in a large sample of elderly subjects free of major cardiovascular disease. CRP levels were not correlated with the AHI and the indices of sleep fragmentation; the ODI >10 events.h(-1) was the strongest predictor of raised CRP level. The present results suggest that, in the elderly, intermittent hypoxaemia may underlie inflammatory processes leading to cardiovascular morbidity.

Cognitive complaints, neuropsychological performance and affective disorders in elderly community residents.

BACKGROUND: Previous studies have assessed the relationship between subjective cognitive complaints and objective impairment. While some of them found that cognitive complaints were explained by affective disorders, other researches found a relationship between cognitive complaints and neuropsychological performance. Most of them focused on memory functioning. However, elderly normal adults also display a decline in executive functions. This study aimed to assess the relationship between cognitive complaints, objective memory and executive performance and affective disorders. METHODS: This study was carried out with 937 community-dwelling elderly individuals recruited from the electoral list of the city of Saint-Etienne, France. Cognitive complaints were assessed using the MacNair scale. Cognitive performances were measured via a large battery of memory and executive-performance tests chosen for their capacity to detect subtle cognitive impairment. Anxiety and depressive symptoms were assessed using scales devised by Pichot and Goldberg. RESULTS: Cognitive complaints were associated with lower scores on verbal-memory tests and several executive-performance tests. Moreover, affective disorders were related to some of the executive-performance test scores, but they were not related to scores on the Free and Cued Selective Reminding Test, Digit Symbol Substitution Test and Trail Making B scores. CONCLUSIONS: Cognitive complaints of the elderly can reflect objective memory and executive-performance impairments, independent of affective disorders. Cognitive complaints should be assessed using both memory and executive-performance tests.

[Performance of the Breastfeeding Assessment Score for the prediction of early weaning in France]. / Intérêt du Breastfeeding Assessment Score pour la prédiction du sevrage précoce de l'allaitement maternel en France.

BACKGROUND: The Breastfeeding Assessment Score (BAS) was derived to help identify mothers at increased risk of early weaning in United States. Data are currently lacking on the accuracy of the BAS for French mother-infant pairs. OBJECTIVE: To assess the accuracy of the BAS in a French validation cohort. METHODS: We used the original data from a prospective cohort study of 488 mothers who were breastfeeding at discharge in 9 maternity wards in 2005. The outcome measures were assessed using structured follow-up telephone interviews at 4 and 26 weeks. RESULTS: The weaning rate was 3% at 14 days of infant age. The corresponding area under ROC curve was 0.73 [0.60-0.85] and was comparable to that observed in the derivation cohort (0.75). For a cut point of 8 recommended by the authors of the BAS, 43% of mother-infant pairs were categorized at high risk and the weaning rate in this subgroup was 5%. The mother-infant pairs with a score lower than 8 had a shorter median breastfeeding duration (18 versus 20 weeks, P=0.02), were more likely to report breastfeeding difficulties after discharge (63% versus 53%, P=0.03), and were less likely to be "very satisfied" with breastfeeding experience (66% versus 77%, P=0.007). CONCLUSION: The intrinsic properties of the BAS are robust. However, its use would be of limited interest in France because of the relatively low rate of early weaning. Randomized trials are needed before recommending routine use of BAS-based breastfeeding support intervention.

Effects of training programs for spinal cord injury.

INTRODUCTION: Endurance exercise training programs in patients with spinal cord injury (SCI) were largely studied to determine different types of adaptations. The aim of specific rehabilitation is to obtain maximal gains in quality-of-life (QoL) after SCI. OBJECTIVE: To review the literature on the efficiency of training programs for SCI. METHODS: We searched the MEDline database with the keywords SCI, paraplegia and quadriplegia and synonyms, then combined them with one of the following terms: rehabilitation, training, exercise conditioning, physical fitness, exercise prescription, adaptation, effect, or benefit. We found 65 articles related to the physiological and psychological effects of training programmes on patients with SCI. RESULTS AND DISCUSSION: Training programs after SCI offer reconditioning cardiorespiratory, cardiovascular, cardiac, metabolic, bone, biomechanical, muscle adaptation, and QoL benefits. Reconditioning training increases VO2 max, reverses leg vascular resistance in the paralyzed legs and has possible cardiac and neural adaptations, favorable catecholamine responses and effects on platelet aggregation. Reconditioning can also modify lipid profile, reduce risk for cardiovascular diseases, prevent osteoporosis and increase maximal upper-extremity muscle strength, sprint power output and maximal power output. This effect allows for considerable improvement in mechanical efficiency and wheelchair propulsion technique. CONCLUSIONS: Reconditioning training programs after SCI have a direct impact on function and QoL, permitting participation in physical activities in addition to daily living activities in subjects with SCI.

Effect of training programs and exercise in adult stroke patients: literature review.

INTRODUCTION: An increasing number of training programs are proposed for the rehabilitation of patients after stroke, with positive results published but without formal validation, and without recommendations regarding indications for specific techniques and procedures. OBJECTIVE: To review data from the literature about training and exercise programs for stroke patients and to describe the efficacy, limitations, and effect of such programs on organ systems. METHODS: A search of MedLINE and relevant medical journals for articles of clinical trials, meta-analyses, and literature reviews pertaining to physical training and exercise programs after stroke. RESULTS: We found 58 articles reporting on various training and exercise techniques (walking, cardiovascular training, muscle strengthening, and others) and their results (on the cardiovascular, musculoskeletal, and neurologic systems, as well as functional status) in hemiplegic stroke patients. DISCUSSION-CONCLUSION: Training and exercise programs have value in stroke rehabilitation, and published results are, in general, promising. However, differences in the populations tested, methods, and criteria for analysis do not allow for recommending specific procedures.

[Relationship between walking capacity and maximal exercise capacity, strength and motor deficiency in adult hemiplegic stroke patients]. / Relation entre les capacités de marche et les capacités maximales à l'effort, les capacités musculaires et la déficience motrice après hémiplégie vasculaire chez l'adulte.

OBJECTIVE: To evaluate the relation between walking capacity and maximal exercise capacity, strength and motor deficiency in hemiplegic stroke patients. DESIGN: Uncontrolled observational study. SETTING: Physical medicine and rehabilitation unit in a teaching hospital. PARTICIPANTS: Twenty hemiplegic stroke patients (17 men and 3 women) aged 18-70 years, whose stroke occurred more than 3 months before the study and who could walk independently with or without walking aids. MAIN OUTCOME MEASURES: Peak oxygen uptake (VO(2peak)), maximal power output walking capacity (6-min walk test) and motor deficiency (Fugl-Meyer scale). RESULTS: Walking capacity was correlated with both VO(2peak) and maximal power output (Pmax) [r=0.609, P<0.003 and r=0.868, P<0.0001, respectively] but also with strength (from r=0.640 to r=0.734; P=0.0018 to P=0.0001) and motor deficiency (r=0.6; P=0.004). CONCLUSIONS: Aerobic capacity and walking capacity are correlated and decreased in hemiplegic stroke patients. These results underscore the need for future studies to confirm the role of fitness in relation to walking capacity and to evaluate the benefit of integrating aerobic training into more traditional rehabilitation programs after stroke.

[Dyspnea of effort associated with a congenital aortic malformation]. / Une dyspnée d'exercice associée à une malformation aortique congénitale.

INTRODUCTION: We report the case of a young woman presenting with dyspnoea of effort. Her records noted that correction of a double aortic arch had been performed in the neonatal period. At rest her flow/volume loop showed a moderate reduction of peak flow without an expiratory plateau. Exercise capacity was limited by sudden onset, during the last 2 stages of the test, of inspiratory dyspnea and tachypnea. During recovery there was no evidence of bronchospasm. CASE REPORT: With this picture we suspected upper airway obstruction and bronchoscopy revealed tracheal compression to 50% of normal. CT scan with 3 dimensional reconstruction showed the trachea compressed between 2 aortic branches. In order to confirm that the tracheal compression increased during exercise we induced sympathetic stimulation by a "handgrip" test that reproduced the inspiratory dyspnea and lead to a reduction in inspiratory flows. CONCLUSION: We have thus demonstrated that the increase in tracheal compression leading to limitation of airflow on exercise was due to an increase in aortic pressure and not to an increase in ventilatory flows.