Kai Schenk

Bike Transalp 2008: liquid intake and its effect on the body's fluid homeostasis in the course of a multistage, cross-country, MTB marathon race in the central Alps.

Objectives:To investigate the drinking behavior of the participants in a multi-day mountain bike (MTB) cross-country competition, to monitor its effect on the bodys fluid compartments and body mass, and to evaluate the prevalence of exercise-associated dysnatremia. Design:Descriptive field study. Setting:The Jeantex Bike Transalp Competition 2008 (8 stages; 665.40 km; 21 691 m height). Participants:Twenty-five male, amateur MTB cyclists. Independent Variables:Reported fluid intake during the race, air temperature. Main Outcome Measures:Changes in body mass and body composition from pre to post race and throughout the competition week, serum sodium concentration at finish line of stages 5 and 6. Results:Mean (±SD) hourly fluid intake during the race correlated with air temperature (r = 0.868, P < .05) and ranged between 494 ± 191 mL/h and 754 ± 254 mL/h. In absence of exercise-induced hyponatremia (EAH) cases, we report 5 and 4 cases of asymptomatic post-race hypernatremia, on days 5 and 6, respectively. When related to race time and body mass, the liquid intake during the race (in mL·kg−1·h−1) correlated with post-race serum sodium concentration (stage 5: r = −0.463, P < .05, n = 24; stage 6: r = −0.589, P < .01, n = 23); no correlation was found between the change in body mass from pre to post race and serum sodium concentration at finish line. Conclusions:Ad libitum fluid consumption during competition was spontaneously adjusted to the unsettled weather conditions in the course of the 2008 “Bike Transalp.” The inverse linear relationship between hourly fluid intake and post-race serum sodium concentrations suggests underdrinking to be one contributing factor to the high reported incidence of hypernatremia in the absence of EAH. Experimental studies are requested to confirm this hypothesis and to further examine the pathogenesis of exercise-associated dysnatremia. In this setting, body mass monitoring was not an accurate instrument to control body fluid homeostasis.

Serum 25-hydroxy vitamin D and exercise capacity in COPD.

Janssens and colleagues1 have recently reported that vitamin D deficiency is very common in patients affected by chronic obstructive pulmonary disease (COPD) and that vitamin D status correlates with lung function. In the same issue of Thorax, Quint and Wedzicha2 discuss potential effects of vitamin D deficiency and supplementation in COPD with special focus on immunomodulatory function. However, they do not consider a potential impact of the hormone on muscle mass and function, and consequently on exercise capacity in these patients.3 Since exercise …

Bioimpedance Identifies Body Fluid Loss after Exercise in the Heat: A Pilot Study with Body Cooling

Purpose Assessment of post-exercise changes in hydration with bioimpedance (BI) is complicated by physiological adaptations that affect resistance (R) and reactance (Xc) values. This study investigated exercise-induced changes in R and Xc, independently and in bioelectrical impedance vector analysis, when factors such as increased skin temperature and blood flow and surface electrolyte accumulation are eliminated with a cold shower. Methods Healthy males (n = 14, 24.1±1.7 yr; height (H): 182.4±5.6 cm, body mass: 72.3±6.3 kg) exercised for 1 hr at a self-rated intensity (15 BORG) in an environmental chamber (33°C and 50% relative humidity), then had a cold shower (15 min). Before the run BI, body mass, hematocrit and Posm were measured. After the shower body mass was measured; BI measurements were performed continuously every 20 minutes until R reached a stable level, then hematocrit and Posm were measured again. Results Compared to pre-trial measurements body mass decreased after the run and Posm, Hct, R/H and Xc/H increased (p<0.05) with a corresponding lengthening of the impedance vector along the major axis of the tolerance ellipse (p<0.001). Changes in Posm were negatively related to changes in body mass (r = −0.564, p = 0.036) and changes in Xc/H (r = −0.577, p = 0.041). Conclusions Present findings showed that after a bout of exercise-induced dehydration followed by cold shower the impedance vector lengthened that indicates fluid loss. Additionally, BI values might be useful to evaluate fluid shifts between compartments as lower intracellular fluid loss (changed Xc/R) indicated greater Posm increase.

Ski mountaineering competition: fit for it?

Objective:To examine the physiological characteristics of experienced ski mountaineers and to determine the physical demands of ski mountaineering competition. Design:Descriptive field study. Setting:An international ski mountaineering competition characterized by 20 400 m distance and 1869 m altitude difference that took place in March 2009 in the South Tyrolean Alps (Italy). Participants:Nine healthy and experienced male ski mountaineers. Interventions:Bioimpedance measurements for body composition definition; maximal exercise testing (Bruce protocol) to determine maximal heart rate (HRmax), maximal oxygen uptake (&OV0312;o2max), and ventilatory thresholds (VT1 and VT2) and to define individual exercise intensity zones; HR registration during competition. Main Outcome Measures:Exercise intensity distribution, occurrence of respiratory symptoms. Results:Ventilatory thresholds were found on average at 70.5% ± 5.0% (VT1) and 90.9% ± 2.6% (VT2) of &OV0312;o2max (68.18 ± 6.11 mL·kg−1·minute−1). The overall exercise intensity, defined by the ratio between mean HR during competition and maximal HR in the laboratory (0.87 ± 0.02), was high. Partial times (% of race time) spent competing in 4 defined performance zones were on average 20.4% ± 17.0% (maximal intensity), 59.8% ± 12.5% (high intensity), 12.8% ± 5.6% (moderate intensity), and 7.0% ± 5.9% (low intensity). Five participants reported respiratory discomfort during competition, with cough being the most frequent symptom. Statistical analysis revealed percent body fat mass to correlate with the partial time performed above VT2 (r = 0.782, P < 0.05); the latter was associated with a worse final placement (r = 0.734, P < 0.05). Conclusions:Competitive ski mountaineering is characterized by an important cardiopulmonary strain and requires a high degree of physical fitness.

Effects of massage under hypoxic conditions on exercise-induced muscle damage and physical strain indices in professional soccer players.

Reports based on experiences from masseurs and players, mostly without any scientific background, suggest that the combination of a classical regeneration method (i.e. massage) with exposure to hypoxia may enhance regeneration in soccer. The aim of this study was to evaluate whether this specific combination could affect blood parameters related to muscle damage and physical strain after a soccer game. Approximately 15 hours after two separate championship games, 10 professional male outfield players of the first Austrian division were exposed to normobaric hypoxia (FiO2 13.5% ∼ 4000m) or normoxia for 1 hour (30 minutes rest followed by 30 min massage) (cross-over design). Creatine kinase (CK), urea and uric acid (UA) were measured 4 days before the first game, and 15 and 63 hours after the two games. Match play increased CK values independently of the intervention. No effect of the massage in combination with hypoxia was seen. A trend was found between Δ UA ([UA] 48 hours after exposure minus [UA] before exposure) in response to hypoxia and SaO2 measured in hypoxia (r=0.612, p=0.06). Results show that massage under hypoxic conditions had no additional positive effect on the measured parameters compared to massage alone. Solely the trend of a relationship for Δ UA and SaO2 might indicate that redox alterations are a potential consequence of hypoxic exposure.

Body fluid status and physical demand during the Giro d’Italia

The aim of the study was to investigate changes in hydration status by means of bioelectrical impedance vector analyses (BIVA) and to assess its influence on power output and rating of perceived exertion (RPE) during the Giro d’Italia 2014. Daily bioelectrical impedance analysis were performed on 9 professional road cyclists (age: 28.2 ± 4.7yr, height: 176.0 ± 5.5 cm, weight: 64.7 ± 3.4 kg) during the race. Additionally, body weight, RPE, and power output were recorded throughout the race. Impedance vectors shortened during the race, whereas body weight remained unchanged at the end of the tour when compared to pre-tour. Vector changes were not related to power output or RPE. The shortening of the BIVA vector indicates that fluid gain occurred during the Giro d’Italia. This fluid gain was not reflected by body weight measurements and might be mainly attributed to muscle edema and/or haemodilution. Furthermore, power output and RPE, mostly depending on team tactic, were not affected by the body water increases.

Race performance and exercise intensity of male amateur mountain runners during a multistage mountain marathon competition are not dependent on muscle strength loss or cardiorespiratory fitness.

Abstract Gatterer, H, Schenk, K, Wille, M, Raschner, C, Faulhaber, M, Ferrari, M, and Burtscher, M. Race performance and exercise intensity of male amateur mountain runners during a multistage mountain marathon competition are not dependent on muscle strength loss or cardiorespiratory fitness. J Strength Cond Res 27(8): 2149–2156, 2013—The aims of this study were to quantify the cardiorespiratory fitness level of amateur mountain runners and to characterize the related cardiorespiratory and muscular strain during a multistage competition. Therefore, 16 male amateur participants performed an incremental treadmill test before the Transalpine-Run 2010. Besides race time, heart rate (HR) was monitored using portable HR monitors during all stages, and countermovement jump ability was assessed after each stage. Overall race time and race times of the single stages were not related to any of the cardiorespiratory fitness parameters assessed during the incremental treadmill test (e.g., V[Combining Dot Above]O2max, ventilatory threshold). Average HR during the first stage was 81 ± 7% of the maximal HR and decreased to 73 ± 6% during the following stages. Creatine kinase activity as an indirect marker of muscle damage and strain amounted to 1,100 ± 619 U·L−1 after the third stage and was related to the decrease in the mean HR between stage 1 and stage 2 (r = −0.616, p < 0.05). Jump ability decreased continuously in the course of the race but was not related to exercise intensity. In conclusion, this study showed that race performance during a multistage mountain marathon does not depend on cardiorespiratory fitness parameters determined in the laboratory. Furthermore, the mean HR decreased after the first stage and remained constant during the following stages independent of the decreased muscle strength. We interpret these data to mean that performance differences were a result of insufficient recovery after the first day of multistage mountain running and the different individual pacing strategies. It is worth mentioning that also other factors, not determined in this investigation, could be responsible for the present outcomes (e.g., nutrition, genetics, psychological and environmental factors, or different training programs).

Effects of snow properties on humans breathing into an artificial air pocket - an experimental field study

Breathing under snow, e.g. while buried by a snow avalanche, is possible in the presence of an air pocket, but limited in time as hypoxia and hypercapnia rapidly develop. Snow properties influence levels of hypoxia and hypercapnia, but their effects on ventilation and oxygenation in humans are not fully elucidated yet. We report that in healthy subjects breathing into snow with an artificial air pocket, snow density had a direct influence on ventilation, oxygenation and exhaled CO2. We found that a rapid decline in O2 and increase in CO2 were mainly associated with higher snow densities and led to premature interruption due to critical hypoxia (SpO2 ≤ 75%). However, subjects in the low snow density group demonstrated a higher frequency of test interruptions than expected, due to clinical symptoms related to a rapid CO2 accumulation in the air pocket. Snow properties determine the oxygen support by diffusion from the surrounding snow and the clearance of CO2 by diffusion and absorption. Thus, snow properties are co-responsible for survival during avalanche burial.

Notfallmedizin im alpinen Gelände – Schock-, Schmerztherapie und Atemwegssicherung

Rescue operations in mountain and remote areas pose special challenges for the rescue team and often differ substantially from rescue missions in the urban environment. Given the growing sports and leisure activities in mountains, incidence of alpine emergencies is expected to rise further. The following article describes the treatment of haemorrhagic shock, analgesic therapy and airway management in mountain rescue.Rettungseinsatze im alpinen Gelande stellen das Rettungsteam vor besondere Herausforderungen und unterscheiden sich oft wesentlich von urbanen Rettungseinsatzen. Angesichts der zunehmenden Sport- und Freizeitaktivitaten in den Bergen ist mit einer weiteren Zunahme von alpinen Notfallen zu rechnen. Nachfolgend wird auf spezielle Aspekte der alpinen Notfallmedizin wie die Therapie des hamorrhagischen Schocks, die Analgesie sowie das Atemwegsmanagement eingegangen.