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We investigated the feasibility of closed loop insulin delivery by using a model based upon the coupling of an implanted insulin pump that infuses insulin by intra-peritoneal route and an intravenous enzymatic glucose sensor. Closed Loop Control (CLC) by a proportional, integral and derivative algorithm was initiated in 4 type 1 diabetic subjects, already implanted with both devices (MiniMed-Medtronic, Northridge, CA, USA), and continued for 48 hours. Three meals of 40 g and twice 80 g carbohydrates were served daily. Blood glucose was assessed every 10 minutes for the first two hours of meals and every 30 minutes otherwise. Algorithm parameters were empirically adjusted during the experiment based on antecedent blood glucose levels. CLC in one subject was stopped after 24 hours due to inadequate sensor performance. During CLC, the algorithm kept glucose within 80-240 mg/dl for 84.1% of the time. Algorithm retuning did not change the percentage of glucose >240 mg/dl but increased the percentage within the 80-120 mg/dl range during the final 24 hours. Excluding meals, glucose was <240 mg/dl for 98% of the time. We conclude that once tuning optimization is achieved, automated control of blood glucose is feasible using this model. Optimal closed loop insulin delivery compensations remain to be defined to allow permanent restoration of normal glucose control. [ABSTRACT FROM AUTHOR]

Purpose: In recent years, there has been significant advancement in the guidelines for recovery protocols involving heat or cold water immersion. Yet, comparison between the effects of hot and cold water immersion on key markers of neuromuscular recovery following exercise-induced muscle damage (EIMD) is lacking., Methods: Thirty physically active males completed an individualized and tailored EIMD protocol immediately followed by one of the following recovery interventions: cold water immersion (11 °C, CWI11), hot water immersion (41 °C, HWI41) or warm-bath control (36 °C, CON36). Gastrointestinal temperature was tracked throughout HWI41. Knee extensors' maximal isokinetic strength [peak torque (Tpeak)] and explosive strength [late-phase rate of force development, (RFD100-200)] were measured prior to EIMD (pre-), 24 h (post-24 h) and 48 h (post-48 h) post-EIMD. In addition, pressure pain threshold (PPT) was measured to quantify the recovery from muscle soreness. Surface electromyography signals (sEMG) from the vastus lateralis were captured to extract the rates of electromyography rise (REMGR) and the spectral power in the low-frequency band., Results: At post-48 h, Tpeak returned to baseline values following both CWI11 (-8.3 ± 6.8 %, p = 0.079) and HWI41 (-1.4 ± 4.1%, p = 1). In contrast, RFD100-200 (-2.3 ± 29.3%, p = 1) and PPT (+5.6 ± 14.6%, p = 1) returned to baseline values at post-48 h only following HWI41. Spectral analysis of the sEMG signal revealed that the low-frequency band was significantly increased following CWI11 (+9.0 ± 0.52%, p = 0.012). REMGR was unchanged regardless of the condition (all p > 0.05)., Conclusions: A single session of HWI41, rather than CWI11, improved the recovery of the late-phase rate of force development following EIMD in physically active males. This suggests that in athletic contexts where a rapid force development is a key performance determinant, hot bath should be preferred over cold bath., Competing Interests: Conflict of Interest and Funding Source: The authors report no conflicts of interest. No funding was received for this research is disclosed., (Copyright © 2024 by the American College of Sports Medicine.)

This single-blind, crossover study aimed to measure and evaluate the short-term metabolic responses to continuous and intermittent hypoxic patterns in individuals with obesity. Indirect calorimetry was used to quantify changes in resting metabolic rate (RMR), carbohydrate (CHO ox , %CHO), and fat oxidation (FAT ox , %FAT) in nine individuals with obesity pre and post: 1 ) breathing normoxic air [normoxic sham control (NS-control)], 2 ) breathing continuous hypoxia (CH), or 3 ) breathing intermittent hypoxia (IH). A mean peripheral oxygen saturation ([Formula: see text]) of 80-85% was achieved over a total of 45 min of hypoxia. Throughout each intervention, pulmonary gas exchanges, oxygen consumption (V̇o 2 ) carbon dioxide production (V̇co 2 ), and deoxyhemoglobin concentration (Δ[HHb]) in the vastus lateralis were measured. Both RMR and CHO ox measured pre- and postinterventions were unchanged following each treatment: NS-control, CH, or IH (all P > 0.05). Conversely, a significant increase in FAT ox was evident between pre- and post-IH (+44%, P = 0.048). Although the mean Δ[HHb] values significantly increased during both IH and CH ( P < 0.05), the greatest zenith of Δ[HHb] was achieved in IH compared with CH ( P = 0.002). Furthermore, there was a positive correlation between Δ[HHb] and the shift in FAT ox measured pre- and postintervention. It is suggested that during IH, the increased bouts of muscle hypoxia, revealed by elevated Δ[HHb], coupled with cyclic periods of excess posthypoxia oxygen consumption (EPHOC, inherent to the intermittent pattern) played a significant role in driving the increase in FAT ox post-IH.

Purpose: Hot water immersion (HWI) has gained popularity to promote muscle recovery, despite limited data on the optimal heat dose. The purpose of this study was to compare the responses of two exogenous heat strains on core body temperature, hemodynamic adjustments, and key functional markers of muscle recovery following exercise-induced muscle damage (EIMD)., Methods: Twenty-eight physically active males completed an individually tailored EIMD protocol immediately followed by one of the following recovery interventions: HWI (40°C, HWI 40 ), HWI (41°C, HWI 41 ) or warm water immersion (36°C, CON 36 ). Gastrointestinal temperature (T gi ), hemodynamic adjustments (cardiac output [CO], mean arterial pressure [MAP], and systemic vascular resistance [SVR]), pre-frontal cortex deoxyhemoglobin (HHb), ECG-derived respiratory frequency, and subjective perceptual measures were tracked throughout immersion. In addition, functional markers of muscle fatigue (maximal concentric peak torque [T peak ]) and muscle damage (late-phase rate of force development [RFD 100-200 ]) were measured prior to EIMD (pre-), 24 h (post-24 h), and 48 h (post-48 h) post-EIMD., Results: By the end of immersion, HWI 41 led to significantly higher T gi values than HWI 40 (38.8 ± 0.1 vs. 38.0°C ± 0.6°C, p < 0.001). While MAP was well maintained throughout immersion, only HWI 41 led to increased (HHb) (+4.2 ± 1.47 μM; p = 0.005) and respiratory frequency (+4.0 ± 1.21 breath.min -1 ; p = 0.032). Only HWI 41 mitigated the decline in RFD 100-200 at post-24 h (-7.1 ± 31.8%; p = 0.63) and T peak at post-48 h (-3.1 ± 4.3%, p = 1)., Conclusion: In physically active males, maintaining a core body temperature of ~25 min within the range of 38.5°C-39°C has been found to be effective in improving muscle recovery, while minimizing the risk of excessive physiological heat strain., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

During deep-sea freediving, many freedivers describe symptoms fairly similar to what has been related to inert gas narcosis in scuba divers. This manuscript aims to present the potential mechanisms underlying these symptoms. First, known mechanisms of narcosis are summarized while scuba diving. Then, potential underlying mechanisms involving the toxicity of gases (nitrogen, carbon dioxide and oxygen) are presented in freedivers. As the symptoms are felt during ascent, nitrogen is likely not the only gas involved. Since freedivers are frequently exposed to hypercapnic hypoxia toward the end of the dive, it is proposed that carbon dioxide and oxygen gases both play a major role. Finally, a new "hemodynamic hypothesis" based on the diving reflex is proposed in freedivers. The underlying mechanisms are undoubtedly multifactorial and therefore require further research and a new descriptive name. We propose a new term for these types of symptoms: freediving transient cognitive impairment., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

Purpose: This single-blind, repeated measures study evaluated adaptive and maladaptive responses to continuous and intermittent hypoxic patterns in young adults., Methods: Changes in haematological profile, stress and cardiac damage were measured in ten healthy young participants during three phases: (1) breathing normoxic air (baseline); (2) breathing normoxic air via a mask (Sham-controls); (3) breathing intermittent hypoxia (IH) via a mask, mean peripheral oxygen saturation (SpO 2 ) of 85% ~ 70 min of hypoxia. After a 5-month washout period, participants repeated this three-phase protocol with phase, (4) consisting of continuous hypoxia (CH), mean SpO 2  = 85%, ~ 70 min of hypoxia. Measures of the red blood cell count (RBCc), haemoglobin concentration ([Hb]), haematocrit (Hct), percentage of reticulocytes (% Retics), secretory immunoglobulin A (S-IgA), cortisol, cardiac troponin T (cTnT) and the erythropoietic stimulation index (calculated OFF-score) were compared across treatments., Results: Despite identical hypoxic durations at the same fixed SpO 2 , no significant effects were observed in either CH or Sham-CH control, compared to baseline. While IH and Sham-IH controls demonstrated significant increases in: RBC c ; [Hb]; Hct; and the erythropoietic stimulation index. Notably, the % Retics decreased significantly in response to IH (-31.9%) or Sham-IH control (-23.6%), highlighting the importance of including Sham-controls. No difference was observed in S-IgA, cortisol or cTnT., Conclusion: The IH but not CH pattern significantly increased key adaptive haematological responses, without maladaptive increases in S-IgA, cortisol or cTnT, indicating that the IH hypoxic pattern would be the best method to boost haematological profiles prior to ascent to altitude., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

High-intensity training sessions are known to alter cardiac autonomic modulation. The purpose of this study was to compare the effects of whole-body cryotherapy, contrast water therapy and passive recovery on the time course of cardiac autonomic markers following a standardized HIT session. Eleven runners completed a high intensity session followed by one of the following recovery interventions: whole-body cryotherapy, contrast water therapy or passive recovery. Changes in cardiac autonomic modulation were assessed in supine and standing positions during an active tilt test at pre-, post-14 h and post-38 h. In supine, high-frequency power increased from pre- to post-14 h following whole-body cryotherapy (1661.1±914.5 vs. 2799.0±948.4 ms 2 , respectively; p=0.023) and contrast water therapy (1906.1±1327.9 vs. 4174.3±2762.9 ms 2 , respectively; p=0.004) whereas high frequency power decreased in response to passive recovery (p=0.009). In standing, low-frequency power increased from pre-to post-38 h (1784.3 ± 953.7 vs. 3339.8±1862.7 ms 2 , respectively; p=0.017) leading to an increase in total power from pre- to post-38 h (1990.8 ± 1089.4 vs. 3606.1±1992.0 ms 2 , respectively; p=0.017). Spectral analysis revealed that contrast water therapy appears to be a more efficient recovery strategy than whole-body cryotherapy in restoring cardiac autonomic homeostasis., Competing Interests: No potential conflict of interest was reported by the authors., (Thieme. All rights reserved.)

Abstract Breath-hold divers are known to develop cardiac autonomic changes and brady-arrthymias during prolonged breath-holding (BH). The effects of BH-induced hypoxemia were investigated upon both cardiac autonomic status and arrhythmogenesis by comparing breath-hold divers (BHDs) to non-divers (NDs). Eighteen participants (9 BHDs, 9 NDs) performed a maximal voluntary BH with face immersion. BHDs were asked to perform an additional BH at water surface to increase the degree of hypoxemia. Beat-to-beat changes in heart rate (HR), short-term fractal scaling exponent (DFAα1), the number of arrhythmic events [premature ventricular contractions (PVCs), premature atrial contractions (PACs)] and peripheral oxygen saturation (SpO 2 ) were recorded during and immediately following BH. The corrected QT-intervals (QTc) were analyzed pre- and post-acute BH. A regression-based model was used to split BH into a normoxic (NX) and a hypoxemic phase (HX). During the HX phase of BH, BHDs showed a progressive decrease in DFAα1 during BH with face immersion ( p  < 0.01) and BH with whole-body immersion ( p  < 0.01) whereas NDs did not ( p  > 0.05). In addition, BHDs had more arrhythmic events during the HX of BH with whole-body immersion when compared to the corresponding NX phase (5.9 ± 6.7 vs 0.4 ± 1.3; p  < 0.05; respectively). The number of PVCs was negatively correlated with SpO 2 during BH with whole-body immersion ( r  = -0.72; p  < 0.05). The hypoxemic stage of voluntary BH is concomitant with significant cardiac autonomic changes toward a synergistic sympathetic and parasympathetic stimulation. Co-activation led ultimately to increased bradycardic response and cardiac electrophysiological disturbances.

Purpose: The purpose of this single-blind, repeated measures study was to investigate the effect of two hypoxic patterns, continuous or intermittent on key markers of haematological adaptation, stress and cardiac damage in healthy senior participants., Methods: Fifteen healthy senior participants each followed a three-phase protocol over 3 consecutive weeks: (1) 5 consecutive days of breathing room air without a mask (2) 5 days of normoxic mask breathing (sham, FiO 2  = 21%) (3) 5 days of intermittent hypoxia (IH) tailored to achieve a mean peripheral oxygen saturation (SpO 2 ) of 85% during ~ 70 min of cumulative exposure to hypoxia. After a 5-month washout period, participants were recalled to undertake continuous hypoxia (CH, SpO 2  = 85%, ~ 70 min). The red blood cell count (RBC c ), haemoglobin concentration ([Hb]), haematocrit (Hct), percentage of reticulocytes (% Retics), secretory immunoglobulin A (S-IgA), cortisol, cardiac troponin T (cTnT) and the OFF-score (i.e. [Formula: see text]) were measured., Results: RBC c only increased by day 5 of IH treatment compared to day 5 baseline values (+ 7.7%, p < 0.01) and day 5 Sham values (+ 12.9%, p < 0.01). [Hb] only increased by day 5 of IH treatment compared to day 5 baseline values (+ 14.7%, p < 0.01) and day 5 Sham values (+ 14.3%, p < 0.01). Hct (+ 12.7%, p < 0.01) and the OFF-score (p < 0.05) increased only during the final day of IH treatment. No difference was observed in S-IgA, cortisol or cTnT following IH or CH., Conclusion: These results revealed that inherent differences in the IH and CH hypoxic patterns could provide crucial components required to trigger hematological changes in senior individuals, without eliciting immunological stress responses or damaging the myocardium.

Repeated apneas are associated with severe hypoxemia that may ultimately lead to loss of consciousness in some breath-hold divers. Despite increasing number of practitioners, the relationship between apnea-induced hypoxia and neurocognitive functions is still poorly understood in the sport of free diving. To shed light onto this phenomenon, we examined the impact of long-term breath-hold diving training on attentional processing, short-term memory, and long-term mnesic and executive functions. Thirty-six men matched for age, height, and weight were separated into the following 3 groups: (i) 12 elite breath-hold divers (EBHD), mean static apnea best time 371 s, 105 months mean apnea experience; (ii) 12 novice breath-hold divers, mean best time 243 s, 8.75 months mean apnea experience; and (iii) 12 physical education students with no breath-hold diving experience; all of these participants performed varied written and computerized neuropsychological tasks. Compared with the 2 other groups, the EBHD group was slower to complete the interference card during a Stroop test (F [1,33] = 4.70, p < 0.05), and presented more errors on the interference card (F [1,33] = 2.96, p < 0.05) and a lower total interference score (F [1,33] = 5.64, p < 0.05). The time to complete the interference card test was positively correlated with maximal static apnea duration (r = 0.73, p < 0.05) and the number of years of breath-hold diving training (r = 0.79, p < 0.001). These findings suggest that breath-hold diving training over several years may cause mild, but persistent, short-term memory impairments.

Purpose: The study aims to investigate the effects of moderate intermittent hypoxia (IH) on key cardio-metabolic risk factors in overweight and obese subjects., Methods: Six subjects were exposed to 10 sessions of moderate IH over 2 weeks (based on [Formula: see text]; ~70 min per session). Measures were made of blood glucose (GLU) and lactate (La - ); high (HDLc) and low-density lipoproteins (LDLc); triglycerides (TRG), systolic (SBP), and diastolic blood pressure (DBP); and cardiac autonomic indices [root mean square of successive R-R interval differences (RMSSD) and short-term fractal scaling exponent (DFAα1)]., Results: GLU decreased and La - increased following a single IH session (6.21 ± 1.62 vs. 5.32 ± 1.03 mmol L -1 ; p < 0.05; 1.14 ± 0.21 vs. 1.47 ± 0.22 mmol L -1 ), but no sustained change after 10 sessions of IH occurred (p > 0.05). Conversely, LDLc (3.00 ± 0.68 vs. 2.51 ± 0.60 mmol L -1 ; p < 0.05), LDLc/HDLc ratio (2.52 ± 0.66 vs. 2.26 ± 0.70 mmol L -1 ; p < 0.05), and SBP (118.6 ± 13.3 vs. 109.6 ± 11.3 mmHg; p < 0.05) were all significantly decreased after 10 sessions., Conclusion: A short course of recurrent IH appears to be a safe and effective non-pharmacological method of reducing key cardiovascular risk factors associated with metabolic disorders.

We investigated the oxygen-conserving potential of the human diving response by comparing trained breath-hold divers (BHDs) to non-divers (NDs) during simulated dynamic breath-holding (BH). Changes in haemodynamics [heart rate (HR), stroke volume (SV), cardiac output (CO)] and peripheral muscle oxygenation [oxyhaemoglobin ([HbO 2 ]), deoxyhaemoglobin ([HHb]), total haemoglobin ([tHb]), tissue saturation index (TSI)] and peripheral oxygen saturation (SpO 2 ) were continuously recorded during simulated dynamic BH. BHDs showed a breaking point in HR kinetics at mid-BH immediately preceding a more pronounced drop in HR (-0.86 bpm.% -1 ) while HR kinetics in NDs steadily decreased throughout BH (-0.47 bpm.% -1 ). By contrast, SV remained unchanged during BH in both groups (all P > 0.05). Near-infrared spectroscopy (NIRS) results (mean ± SD) expressed as percentage changes from the initial values showed a lower [HHb] increase for BHDs than for NDs at the cessation of BH (+24.0 ± 10.1 vs. +39.2 ± 9.6%, respectively; P < 0.05). As a result, BHDs showed a [tHb] drop that NDs did not at the end of BH (-7.3 ± 3.2 vs. -3.0 ± 4.7%, respectively; P < 0.05). The most striking finding of the present study was that BHDs presented an increase in oxygen-conserving efficiency due to substantial shifts in both cardiac and peripheral haemodynamics during simulated BH. In addition, the kinetic-based approach we used provides further credence to the concept of an "oxygen-conserving breaking point" in the human diving response.

Purpose: Although it has been demonstrated that the exponential decay model fits the heart rate (HR) kinetics in short static breath holding (BH), this model might be inaccurate when BH is maintained for several minutes. The aim of this study was to build a new meaningful model to quantify HR kinetics during prolonged static BH., Methods: Nonlinear regression analysis was used to build a model able to quantify the beat-to-beat HR reduction kinetics observed in prolonged static BH performed both in air and in immersed condition by 11 trained breath-hold divers. Dynamic changes in cardiac autonomic regulation through heart rate variability indices [root mean square of successive difference of R-R intervals (RMSSD); short-term fractal scaling exponent: (DFAα1)] and peripheral oxygen saturation (SpO2) were also analyzed to strengthen the model., Results: The tri-phasic model showed a sharp exponential drop in HR immediately followed by a slight linear rise up until a breaking point preceding a linear drop in HR. The breaking points had similar level of SpO2 whether in air or in immersed condition (95.1 ± 2.1 vs. 95.2 ± 3.0 %, respectively; P = 0.49), and the subsequent linear drop in HR was concomitant with a shift in cardiac autonomic regulation in air (RMSSD: +109.0 ± 47.8 %; P < 0.001; DFAα1: -18.0 ± 17.4 %; P < 0.05) and in immersion (RMSSD: +112.6 ± 55.8 %; P < 0.001; DFAα1: -26.0 ± 12 %; P < 0.001)., Conclusion: In addition to accurately fitting the HR kinetics, the most striking finding is an "oxygen-conserving breaking point" highlighted by the model, which might be interpreted as unique adaptive feature against hypoxic damages in the human diving bradycardia.

Ischaemia-modified albumin (IMA) is a marker of the release of reactive oxygen species (ROS) during hypoxaemia. In elite divers, breath-hold induces ROS production. Our aim was to evaluate the kinetics of IMA serum levels during apnea. Twenty breath-hold divers were instructed to perform a submaximal static breath-hold. Twenty non-diver subjects served as controls. Blood samples were collected at rest, every minute, at the end of breath-hold, and 10 min after recovery. The IMA level increased after 1 min of breath-hold (p < 0.003) and remained high until recovery. Divers were separated into 2 groups: subjects who held their breath for less than 4 min (G-4) and those who held it for more than 4 min (G+4). After 3 min of apnoea, the increase of IMA was higher in the G-4 group than in the G+4 group (p < 0.008). However, at the end of apnoea, the IMA level did not differ between groups. If IMA level was globally correlated with the apnoea duration, it is interesting to note that the higher IMA level was not found in the best divers. Similarly, if arterial blood oxygen saturation (SpO2) was globally inversely correlated with apnoea duration, the lowest SpO2 at the end of breath-hold was not found in the divers that performed the best apnoea. We concluded that these divers save their oxygen. The IMA level provides a useful measure of resistance to hypoxaemia.

Objective: Symptoms consistent with neurological decompression sickness (DCS) in commercial breath-hold (Ama) divers has been reported from a few districts of Japan. The aim of this study was to detect circulating intravascular bubbles after repetitive breath-hold diving in a local area where DCS has been reported in Ama divers., Methods: The participants were 12 partially assisted (descent using weights) male Ama divers. The equipment (AQUALAB system) consisted of continuous-wave Doppler with a 5-MHz frequency, and the Doppler probe was placed in the precordial site with the ultrasonic wave directed into the pulmonary infundibulum. We carried out continuous monitoring for 10 minutes at the end of the series of repetitive dives, and the recordings were made on numerical tracks and graded in a blind manner by 2 experienced investigators, according to the Spencer Doppler code., Results: Depths and number of dives were 8 to 20 m and 75 to 131 times. Mean diving duration and surface interval were 64 ± 12 seconds and 48 ± 8 seconds, respectively (mean ± SD). We detected the lowest grade of intravascular bubbles (Spencer's grade I) in an Ama diver whose mean surface interval was only 35.2 ± 6.2 seconds. His mean descending, bottom, and ascending times were 10.4 ± 1.6 seconds, 39.2 ± 8 seconds, and 18.2 ± 3.0 seconds, respectively, over the course of 99 dives., Conclusions: Intravascular bubbles may be formed after repetitive breath-hold dives with short surface intervals or after a long breath-holding session in Ama divers. Symptoms consistent with neurological accidents in repetitive breath-hold diving may be caused in part by the intravascular presence of bubbles, indicating the need for safety procedures., (Copyright © 2014 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.)

Trained breath-hold divers (BHDs) are exposed to repeated bouts of intermittent hypoxia and hypercapnia during prolonged breath-holding. It has thus been hypothesized that their specific training may develop enhanced chemo-responsiveness to hypoxia associated with reduced ventilatory response to hypercapnia. Hypercapnic ventilatory responses (HCVR) and hypoxic ventilatory responses at rest (HVRr) and exercise (HVRe) were assessed in BHDs (n=7) and a control group of non-divers (NDs=7). Cardiac output (CO), stroke volume (SV) and heart rate (HR) were also recorded. BHDs presented carbon dioxide sensitivity similar to that of NDs (2.85±1.41 vs. 1.85±0.93Lmin(-1)mmHg(-1), p>0.05, respectively). However, both HVRr (+68%) and HVRe (+31%) were increased in BHDs. CO and HR reached lower values in BHDs than NDs during the hypoxic exercise test. These results suggest that the exposure to repeated bouts of hypoxia/hypercapnia frequently experienced by trained breath-hold divers only enhances their chemo-responsiveness to poikilocapnic hypoxia, without altering HCVR., (Copyright © 2013 Elsevier B.V. All rights reserved.)

While some studies have demonstrated that respiratory muscle endurance training (RMET) improves performances during various exercise modalities, controversy continues about the transfer of RMET effects to swimming performance. The objective of this study was to analyze the added effects of respiratory muscle endurance training (RMET; normocapnic hyperpnea) on the respiratory muscle function and swimming performance of young well-trained swimmers. Two homogenous groups were recruited: ten swimmers performed RMET (RMET group) and ten swimmers performed no RMET (control group). During the 8-week RMET period, all swimmers followed the same training sessions 5-6 times/week. Respiratory muscle strength and endurance, performances on 50- and 200-m trials, effort perception, and dyspnea were assessed before and after the intervention program. The results showed that ventilatory function parameters, chest expansion, respiratory muscle strength and endurance, and performances were improved only in the RMET group. Moreover, perceived exertion and dyspnea were lower in the RMET group in both trials (i.e., 50- and 200-m). Consequently, the swim training associated with RMET was more effective than swim training alone in improving swimming performances. RMET can therefore be considered as a worthwhile ergogenic aid for young competitive swimmers. Key PointsRespiratory muscle endurance training improves the performance.Respiratory muscle endurance training improves the ventilatory function parameters, chest expansion, respiratory muscle strength and endurance.Respiratory muscle endurance training decreases the perceived exertion and dyspnea.Respiratory muscle endurance training can be considered as a worthwhile ergogenic aid for young competitive swimmers.

Purpose: Voluntary breath-holding (BH) elicits several hemodynamic changes, but little is known about maximal static immersed-body BH. We hypothesized that the diving reflex would be strengthened with body immersion and would spare more oxygen than maximal dry static BH, resulting in a longer BH duration., Methods: Eleven trained breath-hold divers (BHDs) performed a maximal dry-body BH and a maximal immersed-body BH. Cardiac output (CO), stroke volume (SV), heart rate (HR), left ventricular end-diastolic volume (LVEDV), contractility index (CTI), and ventricular ejection time (VET) were continuously recorded by bio-impedancemetry (PhysioFlow PF-05). Arterial oxygen saturation (SaO2) was assessed with a finger probe oximeter., Results: In both conditions, BHDs presented a bi-phasic kinetic for CO and a tri-phasic kinetic for SV and HR. In the first phase of immersed-body BH and dry-body BH, results (mean ± SD) expressed as percentage changes from starting values showed decreased CO (55.9 ± 10.4 vs. 39.3 ± 16.8 %, respectively; p < 0.01 between conditions), due to drops in both SV (24.9 ± 16.2 vs. 9.0 ± 8.5 %, respectively; p < 0.05 between conditions) and HR (39.7 ± 16.7 vs. 33.6 ± 17.0 %, respectively; p < 0.01 between conditions). The second phase was marked by an overall stabilization of hemodynamic variables. In the third one, CO kept stabilizing due to increased SV (17.0 ± 20.2 vs. 10.9 ± 13.8 %, respectively; p < 0.05 between conditions) associated with a second HR drop (14.0 ± 10.0 vs. 12.7 ± 8.9 %, respectively; p < 0.01 between conditions)., Conclusion: This study highlights similar time-course patterns for cardiodynamic variables during dry-body and immersed-body BH, although the phenomenon was more pronounced in the latter condition.

The goal of treatment of diabetes mellitus is the achievement of sustained normoglycemia to prevent the complications with the lowest incidence of hypoglycemia. In the same time, it attempts to reduce the hourly and daily constraints due to multiple injections and self monitoring of glycemia. Both intermittent injections and subcutaneous route are inappropriated to extreme precision and flexibility of regulation requested to reach optimal glycemic control and the best quality of life in most diabetic people. The progress in biomaterials and micro-electronics, the availability of stable insulin solutions have permitted to implant a pump with an awaited functional autonomy for 10 years and to perfuse insulin by peritoneal way in a continuous and modulable fashion. The intra-vascular implanted enzymatic glucose sensors, using glucose-oxidase, are able to measure with good accuracy real-time blood glucose for the duration from 6 to 12 months. The combination of these two linked devices implanted in type 1 diabetic patients has given the opportunity to perform the first trials for periods of 48 hours delivering automated insulin according to glycemic variability. This most physiological restoration of insulin function is feasible and appears to represent a possibility for long term treatment of diabetics.

The project to finalize a 'closed loop' insulin delivery according to blood glucose level, i.e. an implanted artificial beta cell, is born from the development of the first miniaturized portable insulin pumps during the 1970s. Continuous improvements in micro-electronics, as well as in the development of biomaterials and stable insulin solutions, have led to the availability of implantable pumps able to infuse insulin by the peritoneal route, in a continuous and programmable way, for several years. These systems represent the most efficient and physiological mode of insulin therapy at the present time. More recently, we have demonstrated during clinical trials that intravascular, implantable, glucose sensors using glucose-oxidase were able to measure with good accuracy real-time blood glucose for several months. The combination of these two devices to form a prototype of implantable artificial beta cell, designated as Long Term Sensor System, allowed us to perform the first trials of closed-loop insulin delivery according to sensor signal for periods of 48 hours in type 1 diabetic patients. This mode of functioning appeared to be feasible and able to establish glucose control closer to physiology than the use of implantable pumps in open-loop, i.e. by adapting insulin delivery according to capillary blood glucose. Although algorithms tuning automated insulin delivery are improvable, the success of these initial trials materializes the perspective of a possible restoration of physiological insulin function by the mean of an implanted artificial beta cell in diabetic patients.

Purpose: Functional results of total colectomy (TC) and ileorectal anastomosis for colonic inertia are often impaired by postoperative obstruction and diarrhea. In order to avoid these postoperative complications, we propose a subtotal colectomy (STC) preserving the ileo-caecal junction., Methods: Since 1989, 18 consecutive patients (17 F, 1 M; mean age: 54 years) with intractable constipation underwent TC (n = 6) or STC with caecorectal anastomosis (Deloyers Procedure) (n = 12). Mean preoperative bowel frequency was two movements every month. Colonic inertia was defined as diffuse marker delay during transit study without obstructed defecation on manometry or digitalised rectography. Rectocele (n = 10), rectal (n = 5) and genital prolapse (n = 6) were treated in the same operative time., Results: Postoperative course was uneventful after STC but bowel obstruction, requiring laparotomy, occurred in 3 patients (50%) after TC: enterolysis (n = 2), bowel resection (n = 2). Mean postoperative day stool frequency of TC (4.2 +/- 1.2) was higher than STC (1.2 +/- 0.1). Half of patients after TC needed anti-diarrheal treatment and diet, 33% had rectal evacuation difficulties despite liquid stools, 17% had episodic incontinence, 66% had persistent abdominal pain. Compared to TC, the functional results of STC were significantly better: regular normal transit return without diet or treatment in 75% of cases, 25% had rectal emptying difficulties easily treated by mild laxatives, only 17% had persistent abdominal pain. Postoperative obstruction, diarrhea or fecal incontinence never occurred after STC., Conclusion: Compared to TC, STC with Deloyers procedure seems to reduce significantly the postoperative incidence of bowel obstruction, diarrhea and abdominal pain. Expected regular transit return after STC needs a careful selection of patients and simultaneous treatment of ano-rectal and pelvic floor abnormalities frequently associated with colonic inertia.

The feasibility of the continuous intraperitoneal insulin infusion from implantable programmable systems was evaluated in 17 Type 1 (insulin-dependent) diabetic patients currently treated by external pumps. Eight subjects were using a continuous subcutaneous insulin infusion (cumulated experience: 7.4 patients x years) and nine subjects had a cumulated experience of 61.4 patients x years of continuous intra peritoneal insulin delivery by external pumps. The two studied implantable systems (A and B) were delivering the same pH neutral surfactant-stabilized semi-synthetic human insulin, but at the respective concentrations of 400 units per ml in group A (n = 12) and of 100 units per ml in group B (n = 5), via a peritoneal catheter. The pump was implanted in a subcutaneous pocket created in the abdominal wall under general anesthesia. The reported trial of implantable programmable systems is 21 patient x years with an individual experience of 1.2 +/- 0.4 years (mean +/- SD). A sustained and stable glycaemic control was obtained, as indicated by the haemoglobin A1c: 7.4 +/- 1.3% (normal range: 4.3-6.1%), the mean blood glucose: 7.4 +/- 2.1 mM.l-1, the standard deviation of blood glucose values: 3.4 +/- 0.4 mM.l-1 and the percentages of 13.1 +/- 4.5% and 6.1 +/- 6.1% of blood glucose values respectively over 11 mM.l-1 and under 2.8 mM.l-1 after one year. The only metabolic event to occur was one episode of ketoacidosis secondary to a catheter obstruction. No hypoglycaemic coma occurred contrasting with incidences of 0.54 and 0.05 per patient x year during subcutaneous external and intraperitoneal pumps respectively (p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

The difficulties for evaluation of the perineal descent have always been linked to the choice of references and mostly with the incertitude of the measurement of length on the radiographic film. This present study was carried out to evaluate the perineal descent on the choice of an angular measurement: the posterior rectal inclination. The dynamic digitalized rectography was used to investigate the pelvic floor status of 134 women: 115 patients complaining of idiopathic constipation, and 19 healthy volunteers. Results have shown 3 populations with an increasing graduation of perineal impairment and led to propose a radiologic classification of pelvic floor impairment: stage I, or solid perineum, stage II, or descending perineum and stage III or descended perineum. This study has brought up that the first sign of a pelvic floor abnormality may be increased descent during straining, only later followed by perineal descent at rest. The relationship linking abnormal perineal descent and excessive opening of the ano-rectal angle suggested logically that fecal incontinence may be the end complication of the Descending Perineum Syndrom.

We propose an original technique of treatment of perforated peptic ulcer with celioscopic monitoring which has principles and indications similar to those of simple surgical suture via laparotomy. The procedure consists in obliterating the ulcerous perforation with the round ligament (RL) that has previously been predicled from its insertion on the liver, under celioscopy. The umbilical end of the RL is then caught with a Dormia probe inserted through the perforation with a fibrogastroscope. By pulling the probe, the RL is then inserted into the perforation and obturates it. Peritoneal washing and transcutaneous infrahepatic drainage complete the procedure. This was proposed to 9 patients (8 M, 1 F) with a mean age of 41 years (24-59) having ulcers perforated for less than 6 hours. The obliteration of the perforation using the RL was performed easily in 7 cases. In 3 cases, the procedure could not be carried out, either because the diameter of the perforation exceeded 1.5 cm (n = 2) or because of purulent peritonitis (n = 1). No postoperative complications occurred. The endoscopic control showed healed ulcers in all cases after 5 weeks of treatment with anti-H2 drugs. These still preliminary results suggest that the celioendoscopic treatment of perforated peptic ulcers might be proposed whenever vagotomy does not seem to be absolutely necessary, especially in cases of acute ulcer occurring in younger subjects. In comparison with laparotomy, this procedure prevents parietal sequellae and improves the postoperative comfort. This procedure might also be proposed as an alternative to Taylor's procedure, thus avoiding the diagnostic errors and delays in surgery that are inherent in this therapeutic method.

The authors propose a technique of fixation of the parietal prosthesis by metallic staples in order to reduce the operation time which is often long. The operation was performed according to J Rive's principles, using a Dacron patch (n = 65) or a polyglactin patch (n = 5). A mechanical stapler for aponeurotic suture was used for fixation of the patch. The bent shape of the stapler made it possible to very easily insert the lateral edge of the patch, previously hemmed, to slip it under the rectus abdominis muscle and to clamp it onto the lateral linea alba. We placed the patch under tension very easily with circular clamping. Seventy ruptures were treated by this technique. In 80% of cases, the rupture was frontal and in 20% of cases, it was fronto-lateral. The mean diameter of the parietal defect was 15 cm (E = 10-35 cm). The time for fixation of prosthesis was less than 5 min; the usual duration of the operation was therefore considerably reduced. In every case, we obtained optimal tension of the suture, without any folds, and this very easily. There was no mortality. Two postoperative hematomas, one consecutive to an injury of the epigastric artery required a second operation. We only had one case of superficial parietal sepsis. None of these complications required removal of the parietal prosthesis. The functional results were always satisfactory for the patients who suffered no pain induration over the metallic staples. A radiological follow-up of the position of the prosthesis encircled by the metallic staples was systematically performed after every operation. Only one relapse, due to a technical error, was observed. If we consider that the follow-up of these results is about two years (3 months-5 years), they suggest that the use of a stapler allows strong fixation, without any fold and with a regular tension, of the prosthetic patch used in the treatment of large incisional hernia. If we compare this technique with the usual techniques of fixation, we can say that this technique significantly reduces the duration of the operation which is often long. These technical advantages help to reduce the long operating time and the risk of sepsis, which is always serious, also minimizing recurrences of the rupture.

Rectopexy associated with anterior prolepsectomy was performed for 22 patients (19 females, 3 males), with solitary rectal ulcer syndrome (SRUS) surrounding internal rectal prolapse. The different lesions of SRUS were distributed among 3 main groups (G) according to the macroscopic appearance: G1: solitary ulcer (n = 7); G2: ulcerated proctitis (n = 7); G3: muco-hemorroidal prolapse (n = 3). A significant difference (P less than 0.05) was observed between each group, concerning mean age (G1: 34 years, G2 = 49, G3: 65) and the degree of perineal descent, which was more important in G3 and G2. Posterior intersphincteric rectopexy was performed for 6 patients in G3, with descending perineum and faecal incontinence, treated in the same time by perineoplasty (Parks). Abdominal rectopexy, mainly by the antero-posterior technique (Nicholls), was performed for the other patients (n = 6). Large anterior prolapsectomy reaching the top of the mucosal prolapse (4-7 cm), allowing ulcer resection in 3 cases, was combined with rectopexy. Associated operations were: sphincterotomy (n = 8) for narrow fibrous anal canal, sigmoidectomy (n = 4) for dolichocolon. Mean healing time for the solitary ulcer group (G1) was 2 months, 1 month for lesion of G2 and G3. Failures concerned 1 solitary ulcer after abdominal rectopexy and 1 ulcerative proctitis after rectopexy without prolapsectomy. Anorectal pain (81%), rectal bleeding (76%), faecal incontinence (27%), straining (81%), were cured or improved in 80% of cases. These results tend to confirm the efficacy of rectopexy, specially using the antero-posterior technique, for the treatment of SUSR with internal rectal prolapse. Nevertheless, rectopexy seems to be insufficient to correct the mucosal component of internal rectal prolapse, bearing the ulcerated lesion which needs to be treated by associated anterior prolapsectomy. Similarly all functional or organic disorders involving the perineum, anal canal or colon leading to anorectal dysfunction must also be considered to ensure complete treatment.

We report the results of 30 antero-posterior rectopexies (APR) for rectal kinetic disorders with descending perineum syndrome. All patients were investigated by digital subtraction defecography and ano-rectal manometry. The associated surgical procedures were: sphincterotomy (n = 13) for outlet obstruction demonstrated by anal manometry or balloon expulsion test: hypertonic sphincter (n = 7), narrow fibrous sphincter (n = 6); 10 cases of prolapsectomy with extended anterior mucosectomy to reduce anterior rectal prolapse; 2 sigmoidectomy for dolichosigmoid. Best results (mean follow-up: 12 months, 3-26) were observed for ano-rectal or pelvic pain and rectal bleeding, which were cured in more than 80% of cases. Faecal incontinence (n = 5) was cured in all cases. Although normalisation of bowel movements and easier defecation were observed in 78% of cases, improvement in the dyschezic syndrome was differently perceived by the patients. Postoperative investigation demonstrated the probable cause of surgical failures (23%): impairment of rectal sensitivity (n = 2), anismus (n = 3), motor constipation (n = 4), with dolichosigmoid (n = 3). Severe perineal deficiency was also noted in 4 cases. Solitary ulcer (n = 6), anterior proctitis (n = 8), were cured within 2 months. Postoperative defecography showed correction of rectal intussusception without impairment of anterior rectal motility during defecation. These results confirm the efficacy of ARP for treatment of rectal intussusception or anterior rectocele. This functional rectopexy avoids the rectal "sling effect" of standard rectopexy which usually increases rectal dysfunction. Nevertheless, ARP alone seems to be insufficient when the associated functional or organic disorders implicated in rectal dysfunction are not also corrected, essentially outlet obstruction and dolichosigmoid.