Andrew William Sheel

..Further concerns have been raised in regard to the artificial experimental preparations that Guyton used. Recently reported measurements in humans support Guyton's theoretical and animal work...

..It was hypothesized that as climbing difficulty increased, oxygen consumption ([V02] and heart rate would increase, and that climbing would require utilization of a significant fraction of maximal cycling values...

..We interpret these observations to mean that other factors are more important in determining hypoxic ventilatory control than physical conditioning per se...

..Administration of sildenafil citrate had no effect on heart rate or blood pressure during penile vibratory stimulation in men with spinal cord injury...

..Women use a greater fraction of their ventilatory reserve and have a higher metabolic cost of breathing...

..e., generations spanning millennia). Lastly, the third paper uses acute hypoxia to better understand cardio-pulmonary interactions during exercise. Collectively, these reviews are intended to stimulate additional study and debate...

..We also suggest future directions for this relatively young field, including potential clinical applications of IH research...

..However, detailed sex comparisons are difficult because the number of subjects studied to date has been woefully small...

..The determinants of climbing performance are not clear but may be attributed to trainable variables rather than specific anthropometric characteristics...

..To provide a systematic review of the studies assessing exercise training and inspiratory muscle training (IMT) in individuals for the improved respiratory function of patients with spinal cord injury (SCI)...

..Q(L) and increases in LVR. We attribute these changes to a metaboreflex originating in the diaphragm. Diaphragm and forearm muscle fatigue showed very similar time-dependent effects on LVR and .Q(L)...

..Lastly, we review the effects of healthy aging and recent evidence for a male-female difference with respect to exertional-related dyspnea...

..We attribute the limb vasoconstriction to a metaboreflex originating in the diaphragm, which reaches its threshold for activation during fatiguing contractions...

..We also highlight new findings and controversial questions that would benefit from additional study...

..In males and females matched for lung size women had significantly smaller airway luminal areas. The larger conducting airways in females are significantly smaller than those of males even after controlling for lung size...

..CONCLUSION: The vibrostimulation procedure induced electrocardiographic abnormalities and autonomic dysreflexia in subjects with either cervical or high thoracic SCI...

..The purpose of this study was to test the hypothesis that IH would increase systemic inflammatory markers in healthy human males...

..This brief review summarizes the literature as it pertains to the work of breathing, expiratory flow limitation, and exercise-induced diaphragmatic fatigue in healthy humans...

..Scientific debate surrounds the site of NO production and the stimuli for production. Resolution of these controversial issues will explain the significance of exhaled NO during exercise...

..We suggest that future research should be focused towards understanding the role of altered ventilatory responses in human breath-hold athletes as well as in patients suffering from sleep-disordered breathing...

..30) and day 12 (r = 0.47; P > 0.05). Our findings point to a lack of functional significance of increasing HVR via intermittent hypoxia on ventilatory responses to exercise at sea level...

..Furthermore, we discuss unresolved questions dealing with pulmonary system limitations during exercise in women...

..There is no evidence that the short exposure to hypoxia as part of HVR measurement is a co-intervention when measured repeatedly over 5 days in physiological studies...

..Thus, it appears that intermittent hypoxia has direct cerebrovascular effects that can occur in the absence of changes to the ventilatory and neurovascular control systems...

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..53) (P < 0.05) but AHVR was unrelated to Sa(O(2)) for any groups (P > 0.05). We conclude that resting AHVR does not have a significant role in maintaining Sa(O(2)) during sea-level maximal cycle exercise in men or women...

..These results suggest that during cycling exercise at intensities of 75% VO2max or less, regular training may result in higher %ENT and that ENT is not transferable to an unfamiliar mode of exercise using different muscle groups...

..It also appears that patients with cardiac and noncardiac transplants have an increased reliance on anaerobic energy systems during exercise conditions compared with healthy control subjects...

..In this brief review, we describe the characteristics and causes of each of these proposed pulmonary limitations and their consequences to maximal O2 uptake and exercise performance...

..Recent evidence suggests that these respiratory influences contribute significantly to sympathetic vasomotor outflow and to the distribution of systemic vascular conductances and blood flow in the exercising human...

..This review summarises the current literature on the physiology of RM training in healthy individuals and critically evaluates the possible implications for exercise performance...

..The evidence suggests that these effects are mediated primarily via a muscle metaboreflex with a minor, variable contribution from augmented central expiratory motor output...

..These results also suggest that the two methods of measuring CO(2) response are not completely concordant and that the changes in CO(2) control do not correlate with the increase in the HVR...

..We attribute our findings to a reduced activity of chemosensitive afferents within the inspiratory muscles and may provide a mechanism for some of the whole-body exercise endurance improvements associated with IMT...

..05). The findings in this study conclude that IMF, observed immediately following maximal exercise, demonstrated the same pattern of recovery for both genders...

..9652, respectively) and the mean bias values were low (-0.102+/-2.91, 0.033+/-0.207 and -0.715+/-8.362, respectively). These data suggest that the ambulatory RIP provides reasonable estimates of ventilation during rest and exercise...

..Our findings indicate that the vascular processes required to control blood flow and oxygen supply to cerebral tissue in a healthy human are hindered following exposure to 12 days of isocapnic intermittent hypoxia...

..01), but not when compared with days 4 or 5 (P > 0.05). RMT increases MIP and may improve exercise performance; however, improvements are variable with no differences between men and women...

..This study determined the dose-response effects of inhaled salbutamol (SAL) on time-trial performance and urine concentrations of SAL (cSAL)...

..82) during the post-IH trial. Following IH the rise in MSNA burst frequency was strongly related to the change in HVR (r = 0.79, P < 0.05) suggesting that these sympathetic and ventilatory responses may have common central control...

..Collectively, these findings suggest that women utilize a greater majority of their ventilatory reserve compared to men and this is associated with a higher cost of breathing...

..Transient interstitial pulmonary edema did not occur following sustained steady-state cycling exercise in N or H, indicating that transient edema does not result from pulmonary capillary leakage during sustained submaximal exercise...

..Mean lung density did not change from pre (0.138 +/- 0.014 g/ml)- to postexercise (0.137 +/- 0.011 g/ml). These findings suggest that pulmonary edema does not occur in highly trained females following intense normobaric hypoxic exercise...

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..CONCLUSION: It appears that the prevalence of EIAH in women is slightly greater than the 50% prevalence value that is typically reported for highly fit men...