Lung volumes of extreme breath-hold divers

Achievements in breath-hold diving depend, amongst others, on body oxygen stores at start of dive. A diver with very high lung volumes could increase dive's duration, and attain deeper depths for a given speed. Thus, we hypothesized that extreme breath-hold divers have very high lung volumes. On eight extreme breathhold divers (age 35 + 4 years, height 179 + 7 cm, body mass 76 + 6 kg) and 9 non-diving controls (age 37 + 6 years, height 177 + 4 cm, body mass 81 + 9 kg) residual volume, vital capacity and total lung capacity (TLC) were measured with a body plethysmograph. Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were measured with a spirometer. Peak expiratory flow and flow-volume loops were measured with a pneumotachograph. In divers, but not in controls, volumes and capacities were systematically and significantly (p<0.01, paired t-test) higher than predicted from their body size. Consistently, volumes and capacities were significantly higher in divers than in controls, except for residual volume. Divers' TLC was 22% higher than predicted, and 21% higher than in controls. All divers' TLC was higher than 8 L, two had it higher than 9 L. FVC and FEV1 were significantly higher in divers than in controls. The FEV1/FVC ratio was the same in both groups. We conclude that extreme breath-hold divers may constitute a niche population with physiological characteristics different from those of normal individuals, facilitating the achievement of excellent diving performance

Cellular Glucose Uptake During Breath-Hold Diving in Experienced Male Breath-Hold Divers

Abstract Background The physiological and pathophysiological mechanisms that govern diving, both self-contained underwater breathing apparatus (SCUBA) and breath-hold diving (BH-diving), are in large part well known, even if there are still many unknown aspects, in particular about cell metabolism during BH-diving. The scope of this study was to investigate changes in glycemia, insulinemia, and the catecholamine response to BH-diving, to better understand if the insulin-stimulated glucose uptake mechanism is involved in cellular metabolism in this sport. Methods Twenty male experienced healthy breath-hold divers were studied. Anthropometric information was obtained. Glycemia, insulinemia, and catecholamine response were investigated before and after the series of BH-diving. Results We found a statistically significant decrease in the blood glucose levels between before and after dives (mean 94.3 ± 11.6 vs. 83.5 ± 12.5 mg/dl) P = 0.001 and a statistically significant increase in blood insulin value (median 4.5 range 3.4/6.4 vs. 7.0 range 4.2/10.2 mcgU/ml) P < 0.0001. Also, we found a statistically significant increase of catecholamine production (median 14.0 range 8/18 vs. 15.5 range 10.0/21.0 μg) P < 0.0001. Conclusions The increase in blood insulin during BH-diving associated with the decrease of blood glucose levels could indicate that the upregulating cellular uptake is not caused by activation of the specific glucose transporters. Particular diving-related conditions such as the diving reflex, the intermittent hypoxia/hyperoxia, and the particular environmental condition could play an important role in the mechanism involved in glycemia decrease in BH-diving. Our data confirm that the adaptations to BH-diving are caused by complex mechanisms and involve many peculiar responses still in large part unknown

IS HYPOXIA-INDUCIBLE FACTOR (HIF-1) ALPHA INVOLVED IN TARAVANA SYNDROME?

Breath holding diving (BH) is a discipline practiced by an increasing number of people. BH-divers are exposed to extreme environmental conditions such as: increased hyperbaric pressure and low temperature that caused change in arterial blood gases (1-2) and induced an human diving response which includes bradycardia, reduced cardiac output, increased arterial blood pressure and peripheral vasoconstriction (3). Some of these adaptations are still not fully understood, so we decided to investigate some biomarkers that should be involved in this disorders starting to analyse Hypoxia-inducible factor 1 alpha (HIF-1α). We enrolled in our study 31 healthy free divers from different part of Sicily, aged 41,86 ± 11,41, weight 77,52 ± 11,30 kg, height 175,19 ± 6,13 cm, who practiced this activity for more than 5 years. We asked them to perform 5 consecutive dives at 20 meters, without permanence on the bottom, with free recovery between the different dives. A baseline venous blood sample was taken immediately after surfacing from the 5th dive (less than 3 minutes). The samples were stored to -80 until the analysis were done using ELISA method. The results showed that comparing HIF-1α value before and after the dives, there were an increase in the concentration that started from 158,43 pg/ml and be at end 246,06 pg/ml. In conclusion, the Hypoxia-inducible factor 1 alpha can be considered co-responsible for various phenomena, certainly not with pathological destinies, but rather working with “adaptation” phenomena to this type of activity. These are just the preliminary results that need further investigations to be confirmed

Implications of dietary leucine on muscle mTOR gene expression and redox status in rats following high intensity effort.

Leucine supplementation exerts a positive effect on mTOR pathway that is involved in the synthesis of skeletal muscle protein. In the present study, the capability of a 15-day dietary leucine supplementation (310 mg/kg) to improve the performance in acute high intensity effort and the inductive capacity on skeletal muscle protein anabolism in rats submitted to swimming exercise with a 10% bodyweight load attached to the tail, were studied. A 1.83-fold increase in mTOR gene expression in the treated group was found, while no changes in muscle protein content and rats body weight were observed. An increase in protein oxidation and a significant decrease in catalase were found in treated rats, while no changes in DNA damage, GSH and SOD levels were reported. We found an increase of superoxide anion and hydrogen peroxide/myeloperoxidase system in polymorphonuclear neutrophils obtained by treated group. These outcomes suggest slight enhancement in basal inflammation due to exercise activity via mTOR activation during treatment, without serious impairment of the antioxidant system and cell status. In conclusion, the 15-day leucine supplementation at the given dose, enhanced mTOR gene expression in the presence of acute effort which was also well tolerated by skeletal muscle, but probably too short to improve its anabolic activity

Serum Amino Acid Profile Changes After Repetitive Breath-Hold Dives: A Preliminary Study

Background The aim of this work was to investigate the serum amino acid (AA) changes after a breath-hold diving (BH-diving) training session under several aspects including energy need, fatigue tolerance, nitric oxide (NO) production, antioxidant synthesis and hypoxia adaptation. Twelve trained BH-divers were investigated during an open sea training session and sampled for blood 30 min before the training session, 30 min and 4 h after the training session. Serum samples were assayed for AA changes related to energy request (alanine, histidine, isoleucine, leucine, lysine, methionine, proline threonine, valine), fatigue tolerance (ornithine, phenylalanine, tyrosine), nitric oxide production (citrulline), antioxidant synthesis (cystine, glutamate, glycine) and hypoxia adaptation (serine, taurine). Main results Concerning the AA used as an energy support during physical effort, we found statistically significant decreases for all the investigated AA at T1 and a gradual return to the basal value at T2 even if alanine, proline and theonine still showed a slight significant reduction at this time. Also, the changes related to the AA involved in tolerance to physical effort showed a statistically significant decrease only at T1 respect to pre-diving value and a returned to normal value at T2. Citrulline, involved in NO production, showed a clear significant reduction both at T1 and T2. Concerning AA involved in endogenous antioxidant synthesis, the behaviour of the three AA investigated is different: we found a statistically significant increase in cystine both at T1 and T2, while glycine showed a statistically significant reduction (T1 and T2). Glutamate did not show any statistical difference. Finally, we found a statistically significant decrease in the AA investigated in other hypoxia conditions serine and taurine (T1 and T2). Conclusions Our data seem to indicate that the energetic metabolic request is in large part supported by AA used as substrate for fuel metabolism and that also fatigue tolerance, NO production and antioxidant synthesis are supported by AA. Finally, there are interesting data related to the hypoxia stimulus that indirectly may confirm that the muscle apparatus works under strong exposure conditions notwithstanding the very short/low intensity of exercise, due to the intermittent hypoxia caused by repetitive diving

Genetic predisposition to breath-hold diving-induced hemoptysis: Preliminary study.

Breath-hold diving-induced hemoptysis (BH-DIH) has been reported in about 25% breath-hold divers (BHD) and is characterized by dyspnea, coughing, hemoptysis and chest pain. We investigated whether eNOS G894T, eNOS T786C and ACE insertion/deletion I/D genetic variants, are possible BH-DIH risk factors.info:eu-repo/semantics/publishe

Oxidative stress in breath-hold divers after repetitive dives.

Hyperoxia causes oxidative stress. Breath-hold diving is associated with transient hyperoxia followed by hypoxia and a build-up of carbon dioxide (CO₂), chest-wall compression and significant haemodynamic changes. This study analyses variations in plasma oxidative stress markers after a series of repetitive breath-hold dives.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Endothelial Nitric Oxide Production and Antioxidant Response in Breath-Hold Diving: Genetic Predisposition or Environment Related?

Introduction: Nitric oxide (NO) is an essential signaling molecule modulating the endothelial adaptation during breath-hold diving (BH-diving). This study aimed to investigate changes in NO derivatives (NOx) and total antioxidant capacity (TAC), searching for correlations with different environmental and hyperbaric exposure. Materials and methods: Blood samples were obtained from 50 breath-hold divers (BH-divers) before, and 30 and 60 min after the end of training sessions performed both in a swimming pool or the sea. Samples were tested for NOx and TAC differences in different groups related to their hyperbaric exposure, experience, and additional genetic polymorphism. Results: We found statistically significant differences in NOx plasma concentration during the follow-up (decrease at T30 and increase at T60) compared with the pre-dive values. At T30, we found a significantly lower decrease of NOx in subjects with a higher diving experience, but no difference was detected between the swimming pool and Sea. No significant difference was found in TAC levels, as well as between NOx and TAC levels and the genetic variants. Conclusion: These data showed how NO consumption in BH-diving is significantly lower in the expert group, indicating a possible training-related adaptation process. Data confirm a significant NO use during BH-diving, compatible with the well-known BH-diving related circulatory adaptation suggesting that the reduction in NOx 30 min after diving can be ascribed to the lower NO availability in the first few minutes after the dives. Expert BH-divers suffered higher oxidative stress. A preliminary genetic investigation seems to indicate a less significant influence of genetic predisposition

Endothelial Nitric Oxide Production and Antioxidant Response in Breath-Hold Diving: Genetic Predisposition or Environment Related?

Introduction: Nitric oxide (NO) is an essential signaling molecule modulating the endothelial adaptation during breath-hold diving (BH-diving). This study aimed to investigate changes in NO derivatives (NOx) and total antioxidant capacity (TAC), searching for correlations with different environmental and hyperbaric exposure. Materials and methods: Blood samples were obtained from 50 breath-hold divers (BH-divers) before, and 30 and 60 min after the end of training sessions performed both in a swimming pool or the sea. Samples were tested for NOx and TAC differences in different groups related to their hyperbaric exposure, experience, and additional genetic polymorphism. Results: We found statistically significant differences in NOx plasma concentration during the follow-up (decrease at T30 and increase at T60) compared with the pre-dive values. At T30, we found a significantly lower decrease of NOx in subjects with a higher diving experience, but no difference was detected between the swimming pool and Sea. No significant difference was found in TAC levels, as well as between NOx and TAC levels and the genetic variants. Conclusion: These data showed how NO consumption in BH-diving is significantly lower in the expert group, indicating a possible training-related adaptation process. Data confirm a significant NO use during BH-diving, compatible with the well-known BH-diving related circulatory adaptation suggesting that the reduction in NOx 30 min after diving can be ascribed to the lower NO availability in the first few minutes after the dives. Expert BH-divers suffered higher oxidative stress. A preliminary genetic investigation seems to indicate a less significant influence of genetic predisposition