Cognitive impairments after maximal repeated breath-holding in elite breath-hold divers.

Background: Breath-hold (BH) training over several years may result in mild but persistent neurocognitive impairment. Paradoxically, the acute effects of repeated BH generating intermittent hypoxia on neurocognitive functions are still poorly understood. Therefore, we decided to examine the impact of five-repeated maximal BH on attention, processing speed, and reasoning abilities.

Hot But Not Cold Water Immersion Mitigates the Decline in Rate of Force Development Following Exercise-Induced Muscle Damage.

Purpose: In recent years, there has been significant advancement in the guidelines for recovery protocols involving heat or cold water immersion. However, 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, CWI 11 ), hot water immersion (41°C, HWI 41 ), or warm-bath control (36°C, CON 36 ).

Intermittent normobaric hypoxia alters substrate partitioning and muscle oxygenation in individuals with obesity: implications for fat burning.

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, %CHO), and fat oxidation (FAT, %FAT) in nine individuals with obesity pre and post: ) breathing normoxic air [normoxic sham control (NS-control)], ) breathing continuous hypoxia (CH), or ) 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.

Hot water immersion: Maintaining core body temperature above 38.5°C mitigates muscle fatigue.

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 ), HWI (41°C, HWI ) or warm water immersion (36°C, CON ).

Possible causes of narcosis-like symptoms in freedivers.

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.

Pre-acclimation to altitude in young adults: choosing a hypoxic pattern at sea level which provokes significant haematological adaptations.

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) 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 = 85%, ~ 70 min of hypoxia.

Post-exercise Heart Rate Variability: Whole-body Cryotherapy vs. Contrast Water Therapy.

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.

Autonomic regulation of the heart and arrhythmogenesis in trained breath-hold divers.

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.

Intermittent not continuous hypoxia provoked haematological adaptations in healthy seniors: hypoxic pattern may hold the key.

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 = 21%) (3) 5 days of intermittent hypoxia (IH) tailored to achieve a mean peripheral oxygen saturation (SpO) 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 = 85%, ~ 70 min).

Do elite breath-hold divers suffer from mild short-term memory impairments?

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.

Intermittent hypoxia revisited: a promising non-pharmaceutical strategy to reduce cardio-metabolic risk factors?

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)].

The oxygen-conserving potential of the diving response: A kinetic-based analysis.

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]), deoxyhaemoglobin ([HHb]), total haemoglobin ([tHb]), tissue saturation index (TSI)] and peripheral oxygen saturation (SpO) 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.

Ischaemia-modified albumin during experimental apnoea.

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.

Modeling the diving bradycardia: Toward an "oxygen-conserving breaking point"?

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.

Doppler detection in Ama divers of Japan.

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.

Effect of additional respiratory muscle endurance training in young well-trained swimmers.

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).

Cardio-ventilatory responses to poikilocapnic hypoxia and hypercapnia in trained breath-hold divers.

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).

Hemodynamic adjustments during breath-holding in trained divers.

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.