Exercise on land or in water?

Alain Boussuges1, Olivier Gavarry21French Armed Forces Biomedical Research Institute, Brétigny sur Orge and UMR MD2, Aix-Marseilles University, Marseilles, France; 2Engineering Laboratory for Handicaps. South University of Toulon – Var, La Garde, FranceWe have read with interest the study published in the International Journal of General Medicine entitled “Hypotensive response after water-walking and land walking exercise sessions in healthy trained and untrained women” by Rodriguez et al.1 In this study, the authors investigated cardiovascular changes induced by walking in water in comparison with walking on land. Water exercises are commonly used in rehabilitation programs, particularly patients with mobility problems. Recently, some studies have suggested that exercise performed in water could improve cardiovascular function.2View original paper by Bocalini et al

Hyperoxia Improves Hemodynamic Status During Head-up Tilt Testing in Healthy Volunteers A Randomized Study

International audienceHead-up tilt test is useful for exploring neurally mediated syncope. Adenosine is an ATP derivative implicated in cardiovascular disturbances that occur during head-up tilt test. The aim of the present study was to investigate the impact of hyperoxia on adenosine plasma level and on hemodynamic changes induced by head-up tilt testing. Seventeen healthy male volunteers (mean age 35 AE 11 years) were included in the study. The experiment consisted of 2 head-up tilt tests, 1 session with subjects breathing, through a mask, medical air (FiO 2 ¼ 21%) and 1 session with administration of pure oxygen (FiO 2 ¼ 100%) in double-blind manner. Investigations included continuous monitoring of hemodynamic data and measurement of plasma adenosine levels. No presyncope or syncope was found in 15 of the 17 volunteers. In these subjects, a slight decrease in systolic blood pressure was recorded during orthostatic stress performed under medical air exposure. In contrast, hyperoxia led to increased systolic blood pressure during orthostatic stress when compared with medical air. Furthermore, mean adenosine plasma levels decreased during hyperoxic exposure before (0.31 AE 0.08 mM) and during head-up tilt test (0.33 AE 0.09 mM) when compared with baseline (0.6 AE 0.1 mM). Adenosine plasma level was unchanged during medical air exposure at rest (0.6 AE 0.1 mM), and slightly decreased during orthostatic stress. In 2 volunteers, the head-up tilt test induced a loss of consciousness when breathing air. In these subjects, adenosine plasma level increased during orthostatic stress. In contrast, during hyperoxic exposure, the head-up tilt test did not induce presyncope or syncope. In these 2 volunteers, biological study demonstrated a decrease in adenosine plasma level at both baseline and during orthostatic stress for hyperoxic exposure compared with medical air. These results suggest that hyperoxia was able to increase blood pressure during head-up tilt test via a decrease in plasma adenosine concentration. Our results also suggest that adenosine receptor antagonists are worth trying in neurocardiogenic syncope. (Medicine 95(8):e2876) Abbreviations: AR = adenosine receptor, APL = adenosine plasma level, BP = blood pressure, DBP = diastolic blood pressure, FiO 2 = fraction of inspired oxygen, HR = heart rate, HUT = head-up tilt test, LMM = linear mixed model, PO 2 = partial pressure of oxygen, SBP = systolic blood pressure

A cross-sectional study assessing the contributions of body fat mass and fat-free mass to body mass index scores in male youth rugby players

Background. In some sports such as rugby, a large body size is an advantage, and the desire to gain weight can bring young players to become overweight or obese. The aim of this study was to evaluate the prevalence of overweight and obesity and the contribution of body fat mass index (BFMI) and fat-free mass index (FFMI) to body mass index (BMI) changes among young male rugby players (15-a-side rugby). Methods. The criteria of the International Obesity Task Force were used to define overweight and obesity from BMI. The method of skinfold thickness was used to assess percentage of body fat (%BF), BFMI, and FFMI. Excess body fat was defined by using BFMI and %BF above the 75th percentile. Data were grouped according to the age categories of the French Rugby Federation (U11, under 11 years; U13, under 13 years; U15, under 15 years) and to BMI status (NW normal-weight versus OW/OB overweight/obese). Results. Overall, 32.8% of the young players were overweight, and 13.8% were obese. However, 53% of young players classified as obese and overweight by BMI had an excess body fat by using BFMI above the 75th percentile. FFMI increased significantly between U11 and U13 in both groups, without significant change in BMI and BFMI. Both groups had similar significant gains in BMI and FFMI between U13 and U15, while BFMI only increased significantly in OW/OB (+ 18.5%). The strong correlations between BMI and %BF were systematically lower than those between BMI and BFMI. FFMI was strongly or moderately associated with BFMI. Conclusions. Chart analysis of BFMI and FFMI could be used to distinguish changes in body composition across age categories in young male rugby players classified as normal-weight, overweight, and obese by BMI

Pathophysiological and diagnostic implications of cardiac biomarkers and antidiuretic hormone release in distinguishing immersion pulmonary edema from decompression sickness

Immersion pulmonary edema (IPE) is a misdiagnosed environmental illness caused by water immersion, cold, and exertion. IPE occurs typically during SCUBA diving, snorkeling, and swimming. IPE is sometimes associated with myocardial injury and/or loss of consciousness in water, which may be fatal. IPE is thought to involve hemodynamic and cardiovascular disturbances, but its pathophysiology remains largely unclear, which makes IPE prevention difficult. This observational study aimed to document IPE pathogenesis and improve diagnostic reliability, including distinguishing in some conditions IPE from decompression sickness (DCS), another diving-related disorder. Thirty-one patients (19 IPE, 12 DCS) treated at the Hyperbaric Medicine Department (Ste-Anne hospital, Toulon, France; July 2013–June 2014) were recruited into the study. Ten healthy divers were recruited as controls. We tested: (i) copeptin, a surrogate marker for antidiuretic hormone and a stress marker; (ii) ischemia-modified albumin, an ischemia/hypoxia marker; (iii) brain-natriuretic peptide (BNP), a marker of heart failure, and (iv) ultrasensitive-cardiac troponin-I (cTnI), a marker of myocardial ischemia. We found that copeptin and cardiac biomarkers were higher in IPE versus DCS and controls: (i) copeptin: 68% of IPE patients had a high level versus 25% of DCS patients (P < 0.05) (mean ± standard-deviation: IPE: 53 ± 61 pmol/L; DCS: 15 ± 17; controls: 6 ± 3; IPE versus DCS or controls: P < 0.05); (ii) ischemia-modified albumin: 68% of IPE patients had a high level versus 16% of DCS patients (P < 0.05) (IPE: 123 ± 25 arbitrary-units; DCS: 84 ± 25; controls: 94 ± 7; IPE versus DCS or controls: P < 0.05); (iii) BNP: 53% of IPE patients had a high level, DCS patients having normal values (P < 0.05) (IPE: 383 ± 394 ng/L; DCS: 37 ± 28; controls: 19 ± 15; IPE versus DCS or controls: P < 0.01); (iv) cTnI: 63% of IPE patients had a high level, DCS patients having normal values (P < 0.05) (IPE: 0.66 ± 1.50 μg/L; DCS: 0.0061 ± 0.0040; controls: 0.0090 ± 0.01; IPE versus DCS or controls: P < 0.01). The combined “BNP-cTnI” levels provided most discrimination: all IPE patients, but none of the DCS patients, had elevated levels of either/both of these markers. We propose that antidiuretic hormone acts together with a myocardial ischemic process to promote IPE. Thus, monitoring of antidiuretic hormone and cardiac biomarkers can help to make a quick and reliable diagnosis of IPE

Effets de l'hyperoxie sur la circulation artérielle périphérique du volontaire sain et du patient en choc septique

AIX-MARSEILLE2-BU Méd/Odontol. (130552103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

VARIATIONS DE L'HEMODYNAMIQUE CEREBRALE AU COURS D'UNE APNEE VOLONTAIRE (DES PNEUMOLOGIE)

AIX-MARSEILLE2-BU Méd/Odontol. (130552103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Système neurovégétatif et plongée (aspects cardio-vasculaires)

L étude des mécanismes physiologiques au cours d une plongée subaquatique est essentielle à la compréhension des accidents qui lui sont associés. Le plongeur subit de nombreuses contraintes issues du milieu dans lequel il évolue. L objectif de notre travail a été d appréhender les modifications du contrôle neurovégétatif qui régule le système cardiovasculaire induites par les contraintes rencontrées en plongée telles que l immersion, l exposition au froid, l ambiance hyperbare, l exposition hyperoxique et l exercice physique. Nos investigations ont été réalisées chez le plongeur militaire professionnel (Plongeur Démineur et Nageur de Combats) et chez le volontaire sain novice en plongée. L étude du système neurovégétatif était basée sur l analyse de la variabilité de l intervalle RR (contrôle cardiaque) et de la variabilité de la pression artérielle (contrôle vasculaire). Des mesures ultrasonores (échographie bidimensionnelle et Doppler) et des mesures de tonométrie d applanation ont complété nos données hémodynamiques. Une accélération de la fréquence cardiaque a été observée en début d immersion totale. Une adaptation au mode ventilatoire (SCUBA) et un réchauffement des territoires cutanés pourraient être impliqués dans ce phénomène transitoire. A la sortie des 6 heures d immersion, une déshydratation sévère est présente. Son caractère iso-osmotique est responsable d une faible stimulation de la soif, et par conséquent la correction du déficit hydrique est longue (supérieur à 16 heures). L hyperoxique normobare aigue ralentit la fréquence cardiaque par stimulation de l activité parasympathique et induit une vasoconstriction périphérique qui est régulée par des facteurs locaux (diminution de l activité orthosympathique). Après l exposition hyperoxique, la normalisation de la fréquence cardiaque est rapide tandis que les résistances vasculaires systémiques sont au contraire persistantes ce qui évoque des effets de l hyperoxie dissociés de la périphérie (vaisseaux, contrôle local) et du central (coeur, système neurovégétatif et contractilité du myocarde). Une plongée unique a un retentissement important sur le système cardio-vasculaire. L hypothèse de perturbations à long terme étant soulevée il était important de rechercher des signes d altération chez le plongeur militaire professionnel. L entraînement spécifique à la plongée réalisé par l élève Plongeur Démineur entraîne une augmentation de la compliance artérielle qui est probablement secondaire à l entraînement physique en endurance complémentaire. Par ailleurs, les expositions immergées répétées sont à l origine d une acclimatation au froid des plongeurs. Le nageur de combats, lui, réalise des plongées oxygène. Une altération à long terme de la vasomotricité pouvait être redoutée. Or, l étude comparative avec un groupe contrôle apparié n a pas mis en évidence de signes d altérations vasculaires. En conclusion, la plongée génère d importantes modifications du système cardiovasculaire et de son contrôle neurovégétatif. Néanmoins, des expositions répétées chez le militaire bénéficiant d un entraînement physique régulier ne s accompagnent pas d altérations à long terme.During a dive, subjects undergo environmental stressors such as immersion, cold exposure, increased ambient pressure, hyperoxia and physical exercise. All these stressors may be responsible for changes in cardiovascular system and consequently modified autonomic nervous control. The aim of this work was to assess physiological changes induced by diving to better understand injuries reported during this activity. Investigations were performed in professional divers (military mine clearance divers and elite military oxygen divers). Autonomic nervous activity was assessed by power spectral density of heart rate variability (cardiac control) and blood pressure variability (vasomotor control). Hemodynamic changes were assessed by 2-Dimensional and Doppler echocardiography. Arterial wall compliance was estimated by pulse wave analysis. Heart rate increased during the two first hours of total thermoneutral water immersion without significant changes in power spectral density of heart rate variability. This increase might be attributed to artificial ventilation (SCUBA) and peripheral circulatory changes. Dehydration induced by 6-hours of water immersion involved plasmatic, interstitial and intracellular compartments. Post-water immersion dehydration was iso-osmotic i.e. the thirst sensation was weak. Consequently, marked hemodynamic changes had not returned to baseline 16-hours after water immersion. In healthy young adults, normobaric hyperoxia didn t affect blood pressure but induced an increase in systemic vascular resistances. Sympathetic nervous activity to vasomotor control was decreased during hyperoxia and these changes persisted 10 minutes after the return to ambient air. Heart rate returned to baseline (inferior to 5 minutes) before stoke volume and cardiac output correction (30 minutes). The decrease in heart rate was attributed to an increase in parasympathetic nervous activity. On the other hand, an increase in sympathetic activity was observed during 30 minutes after the end of hyperoxic exposure. These results were in accordance with two distinct phenomena of hyperoxia, one peripheral (local control) and other one central (cardiac autonomic nervous control and myocardial alterations). Several studies have described cardiovascular changes-induced by an acute dive. Given that cardiovascular long-term effects of repeated dives have been suggested, we carried out cardiovascular investigations on professional divers. Military mine clearance divers performed intensive diving training. An increase in arterial compliance was observed and has been attributed to the physical endurance training experienced by military divers. Moreover, some peripheral vascular acclimatization to cold was developed. Military oxygen divers were exposed to daily hyperoxia. We hypothesized long term vascular alterations in this population. However, comparative study with a well-matched control group showed no sign of vascular alteration. In summary, diving activity-induced important cardiovascular changes. Autonomic nervous activity was also modified. However, no long-term cardiovascular alteration was found in well trained military divers.AIX-MARSEILLE2-BU Méd/Odontol. (130552103) / SudocSudocFranceF