Effect of menstrual cycle phase on physiological responses in healthy women at rest and during submaximal exercise at high altitude.

As more women engage in high-altitude activities, understanding how ovarian hormone fluctuations affect their cardiorespiratory system is essential for optimizing acclimatization to these environments. This study investigates the effects of menstrual cycle (MC) phases on physiological responses at rest, during and after submaximal exercise, at high-altitude (barometric pressure 509 ± 6 mmHg; partial pressure of inspired oxygen 96 ± 1 mmHg; ambient temperature 21 ± 2 °C and relative humidity 27 ± 4%) in 16 eumenorrheic women. Gas exchange, hemodynamic responses, heart rate variability and heart rate recovery (HRR) were monitored at low altitude, and then at 3375 m on the Mont Blanc (following nocturnal exposure) during both the early-follicular (EF) and mid-luteal (ML) phases.

Hematological and performance adaptations to altitude training (2,320 m) in elite middle-distance and distance swimmers.

Purpose: Elite swimmers often schedule altitude training camps ahead of major events in an attempt to maximize performance. However, the relationships between altitude-induced hematological changes, markers of training adaptation, and performance changes in such context are unclear. This study assessed hematological status, markers of daily adaptation, and swimming performance in elite middle-distance and distance swimmers during a 22-day altitude training camp at 2,320 m, 2 weeks prior to World Championship qualification competition.

Impact of the Menstrual Cycle on the Cardiovascular and Ventilatory Responses During Exercise in Normoxia and Hypoxia.

Citherlet, Tom, Antoine Raberin, Giorgio Manferdelli, Nicolas Bourdillon, and Grégoire P Millet. Impact of the menstrual cycle (MC) on the cardiovascular and ventilatory responses during exercise in normoxia and hypoxia. 00:00-00, 2024.

Difference in expiratory flow limitations development in normoxia and hypoxia in healthy individuals.

The present study investigated the maintenance/repeatability of expiratory flow limitation (EFL) between normoxia and hypoxia. Fifty-one healthy active individuals (27 men and 24 women) performed a lung function test and a maximal incremental cycling test in both normoxia and hypoxia (inspired oxygen fraction = 0.14) on two separate visits.

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 ).

Fitness Level- and Sex-Related Differences in Pulmonary Limitations to Maximal Exercise in Normoxia and Hypoxia.

Purpose: Both maximal-intensity exercise and altitude exposure challenge the pulmonary system that may reach its maximal capacities. Expiratory flow limitation (EFL) and exercise-induced hypoxemia (EIH) are common in endurance-trained athletes. Furthermore, because of their smaller airways and lung size, women, independently of their fitness level, may be more prone to pulmonary limitations during maximal-intensity exercise, particularly when performed in hypoxic conditions.

Daily cardiac autonomic responses during the Tour de France in a male professional cyclist.

Background: Heart rate variability (HRV) is a common means of monitoring responses to training, yet in professional cycling, one may question its usefulness, particularly during multi-day competitions such as Grand Tours.

Objectives: This study aims to report and analyze HRV responses in a male professional cyclist over a season, including the Tour de France.

Methods: A professional cyclist recorded resting and exercise inter-beat intervals during 5 months, comprising a training period with two altitude sojourns and two competition blocks, including the Tour de France.

Baroreflex sensitivity is blunted in hypoxia independently of changes in inspired carbon dioxide pressure in prematurely born male adults.

Premature birth may result in specific cardiovascular responses to hypoxia and hypercapnia, that might hamper high-altitude acclimatization. This study investigated the consequences of premature birth on baroreflex sensitivity (BRS) under hypoxic, hypobaric and hypercapnic conditions. Seventeen preterm born males (gestational age, 29 ± 1 weeks), and 17 age-matched term born adults (40 ± 0 weeks) underwent consecutive 6-min stages breathing different oxygen and carbon dioxide concentrations at both sea-level and high-altitude (3375 m).

Impaired cerebrovascular CO reactivity at high altitude in prematurely born adults.

Premature birth impairs cardiac and ventilatory responses to both hypoxia and hypercapnia, but little is known about cerebrovascular responses. Both at sea level and after 2 days at high altitude (3375 m), 16 young preterm-born (gestational age, 29 ± 1 weeks) and 15 age-matched term-born (40 ± 0 weeks) adults were exposed to two consecutive 4 min bouts of hyperoxic hypercapnic conditions (3% CO-97% O; 6% CO-94% O), followed by two periods of voluntary hyperventilation-induced hypocapnia. We measured middle cerebral artery blood velocity, end-tidal CO, pulmonary ventilation, beat-by-beat mean arterial pressure and arterialized capillary blood gases.

Recommendations for Women in Mountain Sports and Hypoxia Training/Conditioning.

The (patho-)physiological responses to hypoxia are highly heterogeneous between individuals. In this review, we focused on the roles of sex differences, which emerge as important factors in the regulation of the body's reaction to hypoxia. Several aspects should be considered for future research on hypoxia-related sex differences, particularly altitude training and clinical applications of hypoxia, as these will affect the selection of the optimal dose regarding safety and efficiency.

Women at Altitude: Sex-Related Physiological Responses to Exercise in Hypoxia.

Sex differences in physiological responses to various stressors, including exercise, have been well documented. However, the specific impact of these differences on exposure to hypoxia, both at rest and during exercise, has remained underexplored. Many studies on the physiological responses to hypoxia have either excluded women or included only a limited number without analyzing sex-related differences.

Ventilatory responses to independent and combined hypoxia, hypercapnia and hypobaria in healthy pre-term-born adults.

Pre-term birth is associated with physiological sequelae that persist into adulthood. In particular, modulated ventilatory responsiveness to hypoxia and hypercapnia has been observed in this population. Whether pre-term birth per se causes these effects remains unclear.

The V˙O2max Legacy of Hill and Lupton (1923)-100 Years On.

One hundred years ago, Hill and Lupton introduced the concept of maximal oxygen uptake (V˙O2max), which is regarded as "the principal progenitor of sports physiology." We provide a succinct overview of the evolvement of research on V˙O2max, from Hill and Lupton's initial findings to current debates on limiting factors for V˙O2max and the associated role of convective and diffusive components. Furthermore, we update the current use of V˙O2max in elite endurance sport and clinical settings.

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 ).

AltitudeOmics: effects of 16 days acclimatization to hypobaric hypoxia on muscle oxygen extraction during incremental exercise.

Acute altitude exposure lowers arterial oxygen content ([Formula: see text]) and cardiac output ([Formula: see text]) at peak exercise, whereas O extraction from blood to working muscles remains similar. Acclimatization normalizes [Formula: see text] but not peak [Formula: see text] nor peak oxygen consumption (V̇o). To what extent acclimatization impacts muscle O extraction remains unresolved.

End-tidal carbon dioxide tension is a reliable surrogate of arterial carbon dioxide tension across different oxygen, carbon dioxide and barometric pressures.

https://bit.ly/3YuKPAY.

High-Intensity Interval Training, Performance, and Oxygen Uptake Kinetics in Highly Trained Traditional Rowers.

Purpose: Oxygen uptake kinetics (VO2kinetics) is a measure of an athlete's capacity to respond to variations in energy demands. Faster VO2kinetics is associated with better performance in endurance sports, but optimal training methods to improve VO2kinetics remain unclear. This study compared the effects of 2 high-intensity interval-training (HIIT) programs on traditional rowing performance and VO2kinetics.

Physiological Responses to Exercise in Hypoxia in Preterm Adults: Convective and Diffusive Limitations in the O 2 Transport.

Purpose: Premature birth induces long-term sequelae on the cardiopulmonary system, leading to reduced exercise capacity. However, the mechanisms of this functional impairment during incremental exercise remain unclear. Also, a blunted hypoxic ventilatory response was found in preterm adults, suggesting an increased risk for adverse effects of hypoxia in this population.

Both Hypoxia and Hypobaria Impair Baroreflex Sensitivity but through Different Mechanisms.

Baroreflex sensitivity (BRS) is a measure of cardiovagal baroreflex and is lower in normobaric and hypobaric hypoxia compared to normobaric normoxia. The aim of this study was to assess the effects of hypobaria on BRS in normoxia and hypoxia. Continuous blood pressure and ventilation were recorded in eighteen seated participants in normobaric normoxia (NNx), hypobaric normoxia (HNx), normobaric hypoxia (NHx) and hypobaric hypoxia (HHx).

Brain-muscle interplay during endurance self-paced exercise in normobaric and hypobaric hypoxia.

Hypoxia is one major environmental factor, supposed to mediate central motor command as well as afferent feedbacks at rest and during exercise. By using a comparison of normobaric (NH) and hypobaric (HH) hypoxia with the same ambient pressure in oxygen, we examined the potential differences on the cerebrovascular and muscular regulation interplay during a self-paced aerobic exercise. Sixteen healthy subjects performed three cycling time-trials (250 kJ) in three conditions: HH, NH and normobaric normoxia (NN) after 24 h of exposure.

RMSSD Is More Sensitive to Artifacts Than Frequency-Domain Parameters: Implication in Athletes' Monitoring.

Easy-to-use and accurate heart rate variability (HRV) assessments are essential in athletes' follow-up, but artifacts may lead to erroneous analysis. Artifact detection and correction are the purpose of extensive literature and implemented in dedicated analysis programs. However, the effects of number and/or magnitude of artifacts on various time- or frequency-domain parameters remain unclear.