The Gender Factor

Purpose Antarctic residence holds many challenges to human physiology, like increased psycho-social tension and altered circadian rhythm, known to influence sleep. We assessed changes in sleep patterns during 13 months of overwintering at the German Stations Neumayer II and III from 2008 to 2014, with focus on gender, as many previous investigations were inconclusive regarding gender-based differences or had only included men. Materials & Methods Time in bed, sleep time, sleep efficiency, number of arousals, sleep latency, sleep onset, sleep offset, and physical activity level were determined twice per month during seven overwintering campaigns of n = 54 participants (37 male, 17 female) using actimetry. Data were analyzed using polynomial regression and analysis of covariance for change over time with the covariates gender, inhabited station, overwintering season and influence of physical activity and local sunshine radiation. Results We found overall longer times in bed (p = 0.004) and sleep time (p = 0.014) for women. The covariate gender had a significant influence on time in bed (p<0.001), sleep time (p<0.001), number of arousals (p = 0.04), sleep latency (p = 0.04), and sleep onset (p<0.001). Women separately (p = 0.02), but not men (p = 0.165), showed a linear increase in number of arousals. Physical activity decreased over overwintering time for men (p = 0.003), but not for women (p = 0.174). The decline in local sunshine radiation led to a 48 minutes longer time in bed (p<0.001), 3.8% lower sleep efficiency (p<0.001), a delay of 32 minutes in sleep onset (p<0.001), a delay of 54 minutes in sleep offset (p<0.001), and 11% less daily energy expenditure (p<0.001), for all participants in reaction to the Antarctic winter’s darkness-phase. Conclusions Overwinterings at the Stations Neumayer II and III are associated with significant changes in sleep patterns, with dependences from overwintering time and local sunshine radiation. Gender appears to be an influence, as women showed a declining sleep quality, despite that their physical activity remained unchanged, suggesting other causes such as a higher susceptibility to psycho-social stress and changes in environmental circadian rhythm during long-term isolation in Antarctica

Cardiac Autonomic Modulation and Response to Sub-Maximal Exercise in Chilean Hypertensive Miners

Cardiac autonomic modulation in workers exposed to chronic intermittent hypoxia (CIH) has been poorly studied, especially considering hypertensive ones. Heart rate variability (HRV) has been proven as valuable tool to assess cardiac autonomic modulation under different conditions. The aim of this study is to investigate the cardiac autonomic response related to submaximal exercise (i.e., six-minute walk test, 6MWT) in hypertensive (HT, n = 9) and non-hypertensive (NT, n = 10) workers exposed for > 2 years to CIH. Participants worked on 7-on 7-off days shift between high altitude (HA: > 4.200 m asl) and sea level (SL: < 500 m asl). Data were recorded with electrocardiography (ECG) at morning upon awakening (10 min supine, baseline), then at rest before and after (5 min sitting, pre and post) the 6MWT, performed respectively on the first day of their work shift at HA, and after the second day of SL sojourn. Heart rate was higher at HA in both groups for each measurement (p < 0.01). Parasympathetic indices of HRV were lower in both groups at HA, either in time domain (RMSSD, p < 0.01) and in frequency domain (log HF, p < 0.01), independently from measurement’s time. HRV indices in non-linear domain supported the decrease of vagal tone at HA and showed a reduced signal’s complexity. ECG derived respiration frequency (EDR) was higher at HA in both groups (p < 0.01) with interaction group x altitude (p = 0.012), i.e., higher EDR in HT with respect to NT. No significant difference was found in 6MWT distance regarding altitude for both groups, whereas HT covered a shorter 6MWT distance compared to NT (p < 0.05), both at HA and SL. Besides, conventional arm-cuff blood pressure and oxygen blood saturation values (recorded before, at the end and after 5-min recovery from 6MWT), reported differences related to HA only. HA is the main factor affecting cardiac autonomic modulation, independently from hypertension. However, presence of hypertension was associated with a reduced physical performance independently from altitude, and with higher respiratory frequency at HA

The Association of Fatigue With Decreasing Regularity of Locomotion During an Incremental Test in Trained and Untrained Healthy Adults

Fatigue is a key factor that affects human motion and modulates physiology, biochemistry, and performance. Prolonged cyclic human movements (locomotion primarily) are characterized by a regular pattern, and this extended activity can induce fatigue. However, the relationship between fatigue and regularity has not yet been extensively studied. Wearable sensor methodologies can be used to monitor regularity during standardized treadmill tests (e.g., the widely used Bruce test) and to verify the effects of fatigue on locomotion regularity. Our study on 50 healthy adults [27 males and 23 females; <40 years; five dropouts; and 22 trained (T) and 23 untrained (U) subjects] showed how locomotion regularity follows a parabolic profile during the incremental test, without exception. At the beginning of the trial, increased walking speed in the absence of fatigue is associated with increased regularity (regularity index, RI, a. u., null/unity value for aperiodic/periodic patterns) up until a peak value (RI = 0.909 after 13.8 min for T and RI = 0.915 after 13.4 min for U subjects; median values, n. s.) and which is then generally followed (after 2.8 and 2.5 min, respectively, for T/U, n. s.) by the walk-to-run transition (at 12.1 min for both T and U, n. s.). Regularity then decreases with increased speed/slope/fatigue. The effect of being trained was associated with significantly higher initial regularity [0.845 (T) vs 0.810 (U), p < 0.05 corrected], longer test endurance [23.0 min (T) vs 18.6 min (U)], and prolonged decay of locomotor regularity [8.6 min (T) vs 6.5 min (U)]. In conclusion, the monitoring of locomotion regularity can be applied to the Bruce test, resulting in a consistent time profile. There is evidence of a progressive decrease in regularity following the walk-to-run transition, and these features unveil significant differences among healthy trained and untrained adult subjects

Peripheral skin cooling during hyper-gravity: hemodynamic reactions

Introduction: Orthostatic dysregulation occurs during exposure to an increased gravitational vector and is especially common upon re-entering standard Earth gravity (1 g) after an extended period in microgravity (0 g). External peripheral skin cooling (PSC) has recently been described as a potent countermeasure against orthostatic dysregulation during heat stress and in lower body negative pressure (LBNP) studies. We therefore hypothesized that PSC may also be an effective countermeasure during hyper-gravity exposure (+Gz). Methods: To investigate this, we designed a randomized short-arm human centrifuge (SAHC) experiment (“Coolspin”) to investigate whether PSC could act as a stabilizing factor in cardiovascular function during +Gz. Artificial gravity between +1 g and +4 g was generated by a SAHC. 18 healthy male volunteers completed two runs in the SAHC. PSC was applied during one of the two runs and the other run was conducted without cooling. Each run consisted of a 10-min baseline trial followed by a +Gz step protocol marked by increasing g-forces, with each step being 3 min long. The following parameters were measured: blood pressure (BP), heart rate (HR), stroke volume (SV), total peripheral resistance (TPR), cardiac output (CO). Furthermore, a cumulative stress index for each subject was calculated. Results: +Gz led to significant changes in primary as well as in secondary outcome parameters such as HR, SV, TPR, CO, and BP. However, none of the primary outcome parameters (HR, cumulative stress-index, BP) nor secondary outcome parameters (SV, TPR, CO) showed any significant differences—whether the subject was cooled or not cooled. Systolic BP did, however, tend to be higher amongst the PSC group. Conclusion: In conclusion, PSC during +Gz did not confer any significant impact on hemodynamic activity or orthostatic stability during +Gz. This may be due to lower PSC responsiveness of the test subjects, or an insufficient level of body surface area used for cooling. Further investigations are warranted in order to comprehensively pinpoint the exact degree of PSC needed to serve as a useful countermeasure system during +Gz

The deconditioned and the trained heart: responses to physical exercise in pathological and physiological extreme conditions

The human heart is an amazing hydraulic pump that pushes a non-Newtonian fluid in a system of non-rigid vessels millions of times over the course of a lifetime. The mechanic work of this pump is finely regulated by a complex electrical structure that operates with sophisticated feedback systems. These latter are equipped with peripheral sensors and central and peripheral effectors, in order to ensure that the blood flow to all the body systems is sufficient to satisfy the various basic metabolic needs of life, and to supply of adequate energy necessary for the completion of any external work. The muscle activity required by physical exercise, which goes from simply get up from a chair in an elder to preserve the autonomy at home, to the performance of an ultra-marathon runner, finalized to complete a race against extreme environmental conditions, represents the most important physiologic stress for the heart. To cope with the exercise challenge, the cardiovascular system must be therefore able to adapt its performance ranging from a minimum activation level to the capacity of supporting for long time the maximum cardiac output. Amazingly, the physical work required by the exercise to the heart can be done in a cardiovascular continuum of performance that goes from the diseased heart (as in heart failure and primarily cardiac diseases) to the trained heart of the elite athlete. The five articles reported in this dissertation are linked by an important fil rouge: the ability of the cardiovascular system to cope with extreme conditions, in which the exceptional nature of the stimulus is due to very different factors: for a pathology that directly compromises the heart's response to exercise, the light muscle movements necessary to move an electric-wheelchair can be very "demanding" for the cardiovascular system, while for the trained heart the physical activity requested in conditions of extreme environment underlines an adaptation ability near to the tolerable limits of human possibilities. Throughout this continuum of cardiovascular performance of the human heart, the interaction between the environment (simple daily relation life, microgravity, extreme ambient conditions) and the cardiac response to exercise highlights very close links between the heart and the main control system of its mechanical action, the autonomic nervous system, which represents one of the most ancestral (and thereby important) parts of the entire nervous system. In all the conditions in which the cardiac performance was studied in these five articles, it was important to be able to measure as directly and simultaneously as possible both, the cardiac internal load during exercise and the efficiency of its main neural control factors. In these papers it is shown how, despite the extreme variability of environmental stimuli and the stressful factors that influence the cardiovascular system, HR and HRV represent two adequate tools for synchronously assessing cardiac performance on the one hand and the efficiency of his autonomic control during physical exercise on the other. Furthermore, in some study conditions depicted in these articles, physical stress was also added to mental/psychologic stress: again, the HRV tool proved to be adequate in describing the heart's response to these types of non-muscular stress on the heart. If one considers that this monitoring system is absolutely non-invasive, that it can be analyzed starting from a single biological signal (the electrical activity of the heart), that it easy to use, that does not require sophisticated and expensive instruments, its usefulness in evaluating the adaptability of the heart, both pathological and trained, to the continuous "challenges" that the cardiovascular system has to face is clear. Nevertheless, some aspects are still to be evaluated and will require further studies about the use of these analysis systems: for example, i) finding more correct descriptors of the sympatho-vagal balance, ii) better exploring the non-linear components of the cardiac signal, aiming at evaluating the responses of the systems that do not depend on simple action-reaction feedback mechanisms, iii) assessing new ECG signal descriptors that are more directly correlated with the mechanical characteristics of the heart, iv) evaluating the efficiency of new HR and HRV monitoring systems that do not require the strict processing of the cardiac electrical signal (such as the vascular photoplethysmography), v) evaluating the determination capacity of these analysis tools with respect to the onset of fatigue during a continuous recording, vi) better focusing on the crucial relationships between cardiac and respiratory activity, vii) evaluating the effects of senescence both on the mechanical part and on the autonomic control of the heart, are just some of the several challenges that we will face in the next years. However, I believe that the results obtained so far are very promising and I hope that this field of investigation can be deepened and enriched with new methods to evaluate the cardiovascular efficiency during exercise, especially by expanding the prognostic capabilities of these measurements in the field of cardiovascular pathologies, which is still one of the most important health issues to be addressed in the near future

Effect of sprint versus ball-drill training on physical fitness in young basketball players

Basketball involves high-intensity bouts interspersed with brief/incomplete recovery periods. As a result repeated-sprint ability and change of direction training assume logical validity in basketball. Ball-drill games (BD) were suggested as a viable training to provide a range of specific physiological adaptation in basketball. Therefore, the aim of this study was to compare the effects of BD with Sprint Training (ST), and Generic Training (GT) on sprint ability and agility in basketball players. Thirty male regional-level players (17.3 \ub1 0.8 years, 74.2 \ub1 9.8 kg, 181.7 \ub1 7.3 cm) were matched according to VO2max and Anthropometrics and randomly assigned to 3 training groups: BDG (n=12, 4x4min 3 vs 3 at 95% of HRmax with 3-min passive recovery), STG (n=9, 3x6x20m shuttle running with 20-sec and 4-min recovery between bouts and series respectively) and GTG (n=9, control group, generic basketball technical/tactical exercises). Players were tested before and after 8 training weeks (2 sessions/week, 2hrs/session), for force platform Squat Jump and Countermovement Jump; Yo-Yo Intermittent Recovery Test level 1 (YYIRTL1); Agility T-test (forward, lateral, and backward running); Line sprinting over 5/10/20 m and Line drill (LD). No time x group differences were found in jumping and sprinting performance. Significant improvements were reported for YYIRTL1 in BDG (+21%, p<0.05) and STG (+30%, p<0.05). Agility T-test performance showed significant improvements in BDG (-3.4%, p<0.05) and STG (-4.7%, p<0.05). LD test performance was enhanced in the BDG (-1.3 %, p<0.05) and STG (-2.2%, p<0.05). No significant changes in performance occurred in the GTG. These results showed that BD and ST may enhance aerobic and anaerobic fitness if added to usual training. BD, promoting skill development, should be considered as a valuable training tool when pursuing a holistic performance development in basketball players. Researches addressing the concurrent use of BD and ST are warranted

Occupational Disorders, Daily Workload, and Fitness Levels Among Fitness and Swimming Instructors

7sinoneFew data have been published on occupational disorders among sports instructors, especially regarding those who are expected to continuously practice while teaching. As the number of sports instructors increases, new specific information about their possible injuries, daily workload, and fitness levels is needed. The aim of this study was to assess occupational disorders, cardiorespiratory fitness, and daily workload of fitness (FI) and swimming instructors (SI). An online survey addressing occupational disorders was conducted among 435 instructors (256 FI and 179 SI). In one subgroup (57 FI and 42 SI), cardiorespiratory fitness levels were evaluated using maximal oxygen consumption ((Formula presented.) O2max) as an indicator. Daily workload was assessed by monitoring the heart rate and perception of exertion (using the Borg scale). Of the two groups, FI exhibited a higher 2-year prevalence of musculoskeletal injuries and SI experienced more upper respiratory tract infections. (Formula presented.) O2max ranged from 47.0 to 51.9 ml·kg−1·min−1 and was similar for both FI and SI. Regarding the daily workload, female SI had significantly higher mean heart rate and mean heart rate to maximal heart rate ratio compared to female FI, but no significant differences between male FI and SI were found. No significant differences were observed between the perceived exertion of FI and SI. Preventive strategies for the reduction of occupational disorders in FI and SI are needed.noneMerati G.; Bonato M.; Agnello L.; Grevers D.; Gunga H.-C.; Mendt S.; Maggioni M.A.Merati, G.; Bonato, M.; Agnello, L.; Grevers, D.; Gunga, H. -C.; Mendt, S.; Maggioni, M. A

Cardio-pulmonary evaluation of mentally disabled soccer players

Aim. The aim of this study was to evaluate the cardio-pulmonary adaptations during training and during a match of the regular season in a mentally disabled soccer players' team, in order to better organize a training protocol specific to this disability and to provide information for a more accurate clinical decision about the agonistic practice ability carried out in the Sports Medical Centres. Methods. Nine mentally disabled male subjects (group DIS) and seven able-bodied soccer players (group NOR) matched for age, BMI and years of training volunteered the study. Heart rate (FC), oxygen uptake (VO2) and pulmonary ventilation (VE) were monitored either on field, during 1) a session of athletic training; 2) a simulated game-training protocol; 3) a match of the regular season, or in a laboratory setting; 4) during a submaximal ergometric incremental test. A body composition analysis and a standard spirometry were also performed during the laboratory session. Results. Overall, with respect to NOR subjects DIS athletes were overweight and showed an increased fat mass. During simulated training protocol, DIS group reached lower values of FC, VE and VO2 than NOR group. During training and match, FC in the DIS group were similar, and did not seem to be influenced by the surrounding contest. Conversely, during the laboratory incremental ergometric test, DIS group showed higher values of VE and VO2 than NOR group at each submaximal load. Conclusion. Soccer training for mentally disabled players should be mainly centred on aerobic exercises (i.e. 50% VO2max) with a prevalent ludic component. The use of a heart rate monitor during training to control cardiopulmonary effort should be recommended

Sleep Quality Changes during Overwintering at the German Antarctic Stations Neumayer II and III: The Gender Factor.

PURPOSE:Antarctic residence holds many challenges to human physiology, like increased psycho-social tension and altered circadian rhythm, known to influence sleep. We assessed changes in sleep patterns during 13 months of overwintering at the German Stations Neumayer II and III from 2008 to 2014, with focus on gender, as many previous investigations were inconclusive regarding gender-based differences or had only included men. MATERIALS & METHODS:Time in bed, sleep time, sleep efficiency, number of arousals, sleep latency, sleep onset, sleep offset, and physical activity level were determined twice per month during seven overwintering campaigns of n = 54 participants (37 male, 17 female) using actimetry. Data were analyzed using polynomial regression and analysis of covariance for change over time with the covariates gender, inhabited station, overwintering season and influence of physical activity and local sunshine radiation. RESULTS:We found overall longer times in bed (p = 0.004) and sleep time (p = 0.014) for women. The covariate gender had a significant influence on time in bed (p<0.001), sleep time (p<0.001), number of arousals (p = 0.04), sleep latency (p = 0.04), and sleep onset (p<0.001). Women separately (p = 0.02), but not men (p = 0.165), showed a linear increase in number of arousals. Physical activity decreased over overwintering time for men (p = 0.003), but not for women (p = 0.174). The decline in local sunshine radiation led to a 48 minutes longer time in bed (p<0.001), 3.8% lower sleep efficiency (p<0.001), a delay of 32 minutes in sleep onset (p<0.001), a delay of 54 minutes in sleep offset (p<0.001), and 11% less daily energy expenditure (p<0.001), for all participants in reaction to the Antarctic winter's darkness-phase. CONCLUSIONS:Overwinterings at the Stations Neumayer II and III are associated with significant changes in sleep patterns, with dependences from overwintering time and local sunshine radiation. Gender appears to be an influence, as women showed a declining sleep quality, despite that their physical activity remained unchanged, suggesting other causes such as a higher susceptibility to psycho-social stress and changes in environmental circadian rhythm during long-term isolation in Antarctica