Case-Studies in Physiology: The exercise pressor response to indoor rock climbing

Introduction. This paper assessed the blood pressure, heart rate, and mouth-pressure responses to indoor rock climbing (bouldering) and associated training exercises. Case Presentation. Six well-trained male rock climbers (mean ± SD age = 27.7 ± 4.7 y; stature = 177.7 ± 7.3 cm; mass = 69.8 ± 12.1 kg) completed two boulder problems (6b and 7a+ on the Fontainebleau Scale) and three typical training exercises (Maximum voluntary contraction [MVC] isometric pull-up, 80% MVC pull-ups to fatigue, campus-board to fatigue). Blood pressure and heart rate were measured via an indwelling femoral arterial catheter, and mouth pressure via a mouthpiece manometer. Bouldering evoked a peak systolic pressure of 200 ± 17 mmHg (44 ± 21% increase from baseline), diastolic pressure of 142 ± 26 mmHg (70 ± 32% increase), mean arterial pressure of 163 ± 18 mmHg (56 ± 25% increase), and heart rate of 157 ± 20 b⸱min−1 (81 ± 30% increase). The highest systolic pressure was observed during the campus-board exercise (218 ± 33 mmHg), although individual values as high as 273/189 mmHg were recorded. Peak mouth pressure during climbing was 31 ± 46 mmHg, and this increased independent of climb difficulty. Conclusions. Indoor rock climbing and associated exercises evoke a substantial pressor response, resulting in high blood pressures that may exceed those observed during other resistance exercises. These findings may inform risk stratification for climbers

MEDEX2015: greater sea-level fitness is associated with lower sense of effort during Himalayan trekking without worse acute mountain sickness

This study examined the complex relationships of fitness and hypoxic sensitivity with submaximal exercise responses and acute mountain sickness (AMS) at altitude. Determining these relationships is necessary before fitness or hypoxic sensitivity tests can be recommended to appraise individuals' readiness for altitude. Forty-four trekkers (26 men; 18 women; 20-67 years) completed a loaded walking test and a fitness questionnaire in normoxia to measure and estimate sea-level maximal aerobic capacity (maximum oxygen consumption [[Formula: see text]O2max]), respectively. Participants also completed a hypoxic exercise test to determine hypoxic sensitivity (cardiac, ventilatory, and arterial oxygen saturation responses to acute hypoxia, fraction of inspired oxygen [Fio2] = 0.112). One month later, all participants completed a 3-week trek to 5085 m with the same ascent profile. On ascent to 5085 m, ratings of perceived exertion (RPEascent), fatigue by Brunel Mood Scale, and AMS were recorded daily. At 5085 m, RPE during a fixed workload step test (RPEfixed) and step rate during perceptually regulated exercise (STEPRPE35) were recorded. Greater sea-level [Formula: see text]O2max was associated with, and predicted, lower sense of effort (RPEascent; r = -0.43; p < 0.001; RPEfixed; r = -0.69; p < 0.001) and higher step rate (STEPRPE35; r = 0.62; p < 0.01), but not worse AMS (r = 0.13; p = 0.4) or arterial oxygen desaturation (r = 0.07; p = 0.7). Lower RPEascent was also associated with better mood, including less fatigue (r = 0.57; p < 0.001). Hypoxic sensitivity was not associated with, and did not add to the prediction of submaximal exercise responses or AMS. In conclusion, participants with greater sea-level fitness reported less effort during simulated and actual trekking activities, had better mood (less fatigue), and chose a higher step rate during perceptually regulated exercise, but did not suffer from worse AMS or arterial oxygen desaturation. Simple sea-level fitness tests may be used to aid preparation for high-altitude travel

Local intravascular pressure responses to external negative pressure

Project investigating intravascular pressure responses to cycles of external negative pressure in the lower limb

Cardiorespiratory demands of competitive rock climbing

Rock climbing has become a mainstream sport, contested on the Olympic stage. The work/rest pattern of bouldering is unique among disciplines, and little is known about its physiological demands. This study characterised the cardiorespiratory responses to simulated competition. Eleven elite boulderers (7 male) volunteered to participate (age = 23.3 ± 4.5 years; mass = 68.2 ± 9.7 kg; stature = 1.73 ± 0.06 m; body fat = 10.4% ± 5%). Subjects completed incremental treadmill running to determine maximal capacities. On a separate day, they undertook a simulated Olympic-style climbing competition comprising 5 boulder problems, each separated by 5 min of rest. Pulmonary ventilation, gas exchange, and heart rate were assessed throughout. Total climbing time was 18.9 ± 2.7 min. Bouldering elicited a peak oxygen uptake of 35.8 ± 7.3 mL·kg−1·min−1 (∼75% of treadmill maximum) and a peak heart rate of 162 ± 14 beats·min−1 (∼88% of maximum). Subjects spent 22.9% ± 8.6% of climbing time above the gas exchange threshold. At exercise cessation, there was an abrupt and significant increase in tidal volume (1.4 ± 0.4 vs. 1.8 ± 0.4 L; p = 0.006, d = 0.83) despite unchanged minute ventilation. Cardiorespiratory parameters returned to baseline within 4 min of the rest period. In conclusion, competitive bouldering elicits substantial cardiorespiratory demand and evidence of tidal volume constraint. Further studies are warranted to explore the effect of cardiorespiratory training on climbing performance. Novelty: • Competitive bouldering evokes a high fraction of maximal oxygen uptake and prolonged periods above the gas exchange threshold. • Climbing appears to impose a constraint on tidal volume expansion. • Cardiorespiratory indices in elite climbers return to baseline within 2–4 min.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Initiation of continuous renal replacement therapy versus intermittent hemodialysis in critically ill patients with severe acute kidney injury: a secondary analysis of STARRT-AKI trial

Background: There is controversy regarding the optimal renal-replacement therapy (RRT) modality for critically ill patients with acute kidney injury (AKI). Methods: We conducted a secondary analysis of the STandard versus Accelerated Renal Replacement Therapy in Acute Kidney Injury (STARRT-AKI) trial to compare outcomes among patients who initiated RRT with either continuous renal replacement therapy (CRRT) or intermittent hemodialysis (IHD). We generated a propensity score for the likelihood of receiving CRRT and used inverse probability of treatment with overlap-weighting to address baseline inter-group differences. The primary outcome was a composite of death or RRT dependence at 90-days after randomization. Results: We identified 1590 trial participants who initially received CRRT and 606 who initially received IHD. The composite outcome of death or RRT dependence at 90-days occurred in 823 (51.8%) patients who commenced CRRT and 329 (54.3%) patients who commenced IHD (unadjusted odds ratio (OR) 0.90; 95% confidence interval (CI) 0.75-1.09). After balancing baseline characteristics with overlap weighting, initial receipt of CRRT was associated with a lower risk of death or RRT dependence at 90-days compared with initial receipt of IHD (OR 0.81; 95% CI 0.66-0.99). This association was predominantly driven by a lower risk of RRT dependence at 90-days (OR 0.61; 95% CI 0.39-0.94). Conclusions: In critically ill patients with severe AKI, initiation of CRRT, as compared to IHD, was associated with a significant reduction in the composite outcome of death or RRT dependence at 90-days