Modeling the Power-Duration Relationship in Professional Cyclists During the Giro d'Italia.

ABSTRACT: Vinetti, G, Pollastri, L, Lanfranconi, F, Bruseghini, P, Taboni, A, and Ferretti, G. Modeling the power-duration relationship in professional cyclists during the Giro d'Italia. J Strength Cond Res 37(4): 866-871, 2023-Multistage road bicycle races allow the assessment of maximal mean power output (MMP) over a wide spectrum of durations. By modeling the resulting power-duration relationship, the critical power ( CP ) and the curvature constant ( W' ) can be calculated and, in the 3-parameter (3-p) model, also the maximal instantaneous power ( P0 ). Our aim is to test the 3-p model for the first time in this context and to compare it with the 2-parameter (2-p) model. A team of 9 male professional cyclists participated in the 2014 Giro d'Italia with a crank-based power meter. The maximal mean power output between 10 seconds and 10 minutes were fitted with 3-p, whereas those between 1 and 10 minutes with the 2- model. The level of significance was set at p < 0.05. 3-p yielded CP 357 ± 29 W, W' 13.3 ± 4.2 kJ, and P0 1,330 ± 251 W with a SEE of 10 ± 5 W, 3.0 ± 1.7 kJ, and 507 ± 528 W, respectively. 2-p yielded a CP and W' slightly higher (+4 ± 2 W) and lower (-2.3 ± 1.1 kJ), respectively ( p < 0.001 for both). Model predictions were within ±10 W of the 20-minute MMP of time-trial stages. In conclusion, during a single multistage racing event, the 3-p model accurately described the power-duration relationship over a wider MMP range without physiologically relevant differences in CP with respect to 2-p, potentially offering a noninvasive tool to evaluate competitive cyclists at the peak of training.

Follow-up of Acute Respiratory Disorders in Cyclists Competing in the 100th Giro d'Italia.

Acute respiratory disorder is a common sub-clinical condition affecting elite cyclists. Monitoring the perturbations of the immunological cells in the respiratory tract, indicative of a likely proinflammatory state, during an International Cycling Union world tour is a challenging task. The aim of this study was to follow up on the sign and symptoms of upper way respiratory infections with or without asthma, using non-invasive methods, during a 21-day race (100° Giro d'Italia, 2017). Nine male elite cyclists of the Bahrain Merida Team were evaluated before the training season and daily during the race. Clinical history, skin prick and spirometric test, acute respiratory symptoms were measured using validated questionnaires, and values of fraction of exhaled nitric oxide were collected longitudinally. Four of the 9 athletes had allergies with/or consistent abnormal spirometric curves before the race. During the race, 5 athletes had a fraction of exhaled nitric oxide values >20 ppb which correlated with respiratory symptoms collected through questionnaires. These were related to the environmental characteristics of the places travelled through in the race. The athletes with a predisposition to chronic respiratory inflammation in the pre-competitive season were more likely to develop acute respiratory symptoms during the race.

QTc dispersion and interval changes in drug-free borderline personality disorder adolescents.

Emotional instability and dysregulation represent a core feature of borderline personality disorder (BPD) and abnormal patterns of sympathetic/parasympathetic activity have been repeatedly investigated in individuals with this disorder. Such abnormalities may represent the substrate for an arrhythmogenic risk that could materialize the following specific drug exposure. In this work, we decided to assess basal-corrected QT interval and dispersion (QTc and QTcd) for estimating such risk in a sample of drug-free adolescents with diagnosis of BPD. In this cross-sectional comparative study, we recruited n = 70 female adolescent BPD (14.7 ± 1.3 years), free of medications, alcohol or recreational drugs. Furthermore, n = 70 matched female healthy controls (CTRL, 14.6 ± 1.5 years) were enrolled. QTc and QTcd were manually assessed on a standard 12-lead ECG by a single experienced investigator who was unaware of clinical outcomes. QTcd was increased by 7 ms on average in BPD vs. CTRL (+ 18%, p = 0.03). QTc was decreased by about 15 ms on average in BPD vs. CTRL (p = 0.003). A mild correlation was found between QTc and QTcd in BPD (r = 0.25, p = 0.03) that was not present in CTRL. No correlation was found between either QTc or QTcd, and age in both groups. Mildly increased QTcd characterizes the cardiac activity regardless of drug exposure in female adolescents with BPD. This information may be of value to clinicians striving to use neuroleptic and antidepressant drugs with a lower risk of QTcd increase.

QT interval and dispersion in drug-free anorexia nervosa adolescents: a case control study.

Long QT values have been reported in patients with anorexia nervosa of the restricting type (ANr) potentially increasing the risk of fatal arrhythmia, especially if psychotropic drug treatment is required. Nevertheless, the previous studies on this topic are biased by drug exposure, long disease durations, and small sample sizes. This study is aimed at assessing QTc and QTcd values in ANr adolescents with recent onset and drug free, as compared to subjects affected by psychiatric disorders other than ANr. We evaluated QTc and its dispersion (QTcd) in a population of 77 drug-free ANr female adolescents and compared to an equal number of healthy controls (H-CTRL) and pathological controls (P-CTRL, mixed psychiatric disorders). The QT determination was performed on a standard simultaneous 12-lead ECG in blind by a single experienced investigator. QTc was calculated by the Bazett's formula and QTcd was determined as the difference between the maximum and minimum QTc intervals in different leads. Only for ANr patients, clinico-demographic data, hormones, and electrolytes were obtained. QTc was slightly reduced in ANr patients (27.7 ms, < 10%, p < 0.0003) vs. controls, while QTcd was increased in P-CTRL (30%, p < 0.0003). Heart rate was significantly lower in ANr patients vs. controls (25%; p < 0.003). Tyroid hormones and serum potassium showed weak although significant positive correlations with QTc in ANr patients. QTcd displayed a weak negative correlation with the BMI percentile (r = - 0.262, p = 0.03). We reject the hypothesis that QTc and QTcd are increased in drug-free ANr adolescents with a relatively short-disease duration. Further studies are needed to understand if the previously reported increase might be related to other associated chronic disorders, such as hormonal or electrolyte imbalance.

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 ± 4.7 yr, 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.

The Impact of a Precision-Based Exercise Intervention in Childhood Hematological Malignancies Evaluated by an Adapted Yo-Yo Intermittent Recovery Test.

During cancer treatments in childhood hematological malignancies, reduced exercise tolerance is one of the main hardships. Precision-based training programs help children, adolescents, and young adults and their families to resume regular physical activity, exercise, and sports once they return to their communities after the intensive phases spent in hospital. This study was aimed at verifying whether an intermittent recovery test, the Yo-Yo AD, could provide a simple and valid way to evaluate an individual's capacity to perform repeated intense exercise and to follow up on the impact of tailored exercise in children, adolescents, and young adults with hematological malignancies. The Yo-Yo AD involved the repetition of several shuttles to muscle exhaustion, at pre-established speeds (walking and slow running). The heart rate (HR) and oxygen saturation (SaO2) were monitored during the test. The total distance and the walking/running ability, measured as the slope of the HR vs. distance correlation, were investigated before (T0) and after 11 weeks (T1) of precision exercise intervention. The Yo-Yo AD was also performed by healthy children (CTRL). Ninety-seven patients (10.58 ± 4.5 years, 46% female) were enrolled. The Yo-Yo AD showed the positive impact of the exercise intervention by increasing the distance covered by the individuals (T0 = 946.6 ± 438.2 vs. T1 = 1352.3 ± 600.6 m, p < 0.001) with a more efficient walking/running ability (T0 = 2.17 ± 0.84 vs. T1 = 1.73 ± 0.89 slope, p < 0.0164). CTRLs performed better (1754.0 ± 444.0 m, p = 0.010). They were equally skillful (1.71 ± 0.27 slope) when compared to the patients after they received the precision-based intervention. No adverse events occurred during the Yo-Yo AD and it proved to be an accurate way of correctly depicting the changes in performance in childhood hematological malignancies.

Functional assessment of long bone fracture healing in Samburu County Referral Hospital (Kenya): the squat and smile challenge.

BACKGROUND: The burden of musculoskeletal trauma is increasing in low- and middle-income countries. Due to the low clinical follow-up rates in these regions, the Squat-and-Smile test (S&S) has previously been proposed as a proxy to assess bone healing (BH) capacity after surgery involving bone fractures. This study deals with various aspects of using S&S and bone radiography examination to obtain information about an individual's ability to recover after a trauma. In summary, we performed the S&S test to assess the possibility of recovering biomechanical function in lower limbs in a remote area of Kenya (Samburu County). METHODS: Eighty-nine patients (17.9% F; 31.7 ±â€Š18.9 yrs) who underwent intramedullary nail treatment for femur or tibia fractures were enrolled in this study. Both S&S [evaluated by a goal attainment scale (GAS)] and x-ray (evaluated by REBORNE, Bone Healing Score) were performed at 6 and 24 weeks, postoperatively. An acceptable margin for satisfactory S&S GAS scores was determined by assessing its validity, reliability, and sensitivity. RESULTS: S&S GAS scores increased over time: 80.2% of patients performed a satisfactory S&S at the 24-weeks follow-up with a complete BH. A high correlation between S&S GAS and REBORNE at the 6- and 24- weeks' timepoint was found. Facial expression correlated partially with BH. The S&S proved to be accurate at correctly depicting the BH process (75% area fell under the Receiver Operator Curve). CONCLUSION: The S&S provides a possible substitution for bone x-ray during BH assessment. The potential to remotely follow up the BH is certainly appealing in low- and middle-income countries, but also in high-income countries; as was recently observed with the Covid-19 pandemic when access to a hospital is not conceivable.

Osteopathic Treatment and Evaluation in the Clinical Setting of Childhood Hematological Malignancies.

Children: adolescents, and young who are adults affected with hematological malignancies (CAYA-H) and who are undergoing intensive phases of cancer treatment, including hematopoietic stem cell transplantation (HSCT), experience diminished functional ability. This study was aimed at assessing the feasibility, efficacy, safety, and satisfaction of an osteopathic intervention in CAYA-H attending an 11-week precision-based exercise program (PEx). All of the participants were given 4-10 treatments according to the prescription ordered by the sports medicine doctor in charge of the PEx, and the following outcomes were assessed: (1) spinal column range of motion (ROM) by palpation; (2) lower and upper limb joints ROM by a goniometer; (3) orthostatic posture by plumb line assessment; (4) chest and abdomen mobility by inspection and palpation; (5) cranial-sacral rhythmic impulse (CRI) by palpation; and (6) adverse effects. Goal attainment scaling (GAS) was used to identify the accomplishment of a desired clinical result. Moreover, HSCT patients who were affected with graft-versus-host disease and/or osteonecrosis had their joints assessed in terms of ROM as tools to monitor the effectiveness of immunosuppressive treatment. A total of 231 CAYA-H were identified, and 104 participated in the study (age 10.66 ± 4.51 yrs; 43% F). PEx plus osteopathy reached positive GAS scores by improving the ROMs of the spinal column and/or limbs (81% and 78%, respectively), chest and abdomen mobility (82%), and CRI (76%). Only minor reversible adverse effects were noticed during the study. Together, our data seem to initiate a new course where osteopathy could be useful in evaluating structural edges due to the clinical history of each CAYA-H. Given the contributions that were obtained by the GAS scores, osteopathic treatment seems to reveal interesting potential that can be targeted in the future.

Precision-based exercise as a new therapeutic option for children and adolescents with haematological malignancies.

Children and adolescents with haematological malignancies (PedHM) are characterized by a severe loss of exercise ability during cancer treatment, lasting throughout their lives once healed and impacting their social inclusion prospects. The investigation of the effect of a precision-based exercise program on the connections between systems of the body in PedHM patients is the new frontier in clinical exercise physiology. This study is aimed at evaluating the effects of 11 weeks (3 times weekly) of combined training (cardiorespiratory, resistance, balance and flexibility) on the exercise intolerance in PedHM patients. Two-hundred twenty-six PedHM patients were recruited (47% F). High or medium frequency participation (HAd and MAd) was considered when a participant joined; > 65% or between 30% and < 64% of training sessions, respectively. The "up and down stairs'' test (TUDS), "6 min walking" test (6MWT), the "5 Repetition Maximum strength" leg extension and arm lateral raise test (5RM-LE and 5RM-ALR), flexibility (stand and reach), and balance (stabilometry), were performed and evaluated before and after training. The TUDS, the 5RM-LE and 5RM-ALR, and the flexibility exercises showed an increase in HAd and MAd groups (P < 0.05), while the 6MWT and balance tests showed improvement only in HAd group (P < 0.0001). These results support the ever-growing theory that, in the case of the treatment of PedHM, 'exercise is medicine' and it has the potential to increase the patient's chances of social inclusion.

Tailored Exercise Training Counteracts Muscle Disuse and Attenuates Reductions in Physical Function in Individuals With Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease, characterized by the progressive loss of motor neurons, which leads to a reduction in strength and exercise capacity. Although the concept of "Exercise is Medicine" is accepted for many diseases, the role of exercise in individuals with ALS is still debated. The aim of this study was to propose a tailored exercise training program that was both safe and effective for individuals with ALS, and to evaluate the effects of this combined, moderate-intensity, aerobic and strength training program on aerobic capacities, strength, and physical function. Sixteen individuals with ALS were randomly assigned to either a training (three times a week for 12 weeks; TRAIN, n = 8) or usual care (continued their usual standard of care and served as control; UC, n = 8) group. Peak power, peak oxygen uptake, as well as the gas exchange threshold (GET) during a cardiopulmonary exercise test (CPET) on a cycle ergometer, and the maximal strength (1RM) of the knee extensor muscles, were evaluated before and after 12 weeks. Participants also performed the "Timed Up and Go" (TUG) and the "6-min walking" (6MWT) tests. The ALS Functional Rating Scale revisited (ALSFRS-R), the ALS Severity Scale (ALS-SS), and the McGill quality of life (QoL) questionnaire were also measured. The GET increased from 0.94 ± 0.08 to 1.06 ± 0.10 L min-1 in TRAIN (p = 0.009) and decreased from 0.79 ± 0.17 to 0.72 ± 0.17 L min-1 in UC (p = 0.001). There was a significant difference between groups for changes in TUG (9.1 ± 5.5% improvement in TRAIN and 56.8 ± 18.5% worsening in UC, p = 0.002), ALSFRS-R (4.7 ± 2.6% decrease in TRAIN and 23.0 ± 5.6% decrease in UC, p = 0.007), and for the ALS-SS (2.2 ± 2.1% decrease in TRAIN and 12.4 ± 4.4% decrease in UC, p = 0.04). Even if the 1RM of the knee-extensor muscles showed a tendency to increase in TRAIN (70.1 ± 30.0%, p = 0.07), there was not a statistically significant difference (p = 0.57) with respect to the changes in the UC group (44.9 ± 20.7% increase, p = 0.11). This study showed that a combined moderate-intensity aerobic and strength training program, tailored to the physical capacities of each individual, can improve aerobic fitness and maintain physical function in individuals with ALS.

Impact of Hanging Motionless in Harness on Respiratory and Blood Pressure Reflex Modulation in Mountain Climbers.

Harness hang syncope (HHS) is a risk that specifically affects safety of harness users in mountain climbing. Aims: To evaluate individual patterns of breathing resulting from deranged cardiovascular reflexes triggering a syncopal event when a mismatch between cerebral O2 demand and supply is present. Results: Forty healthy participants [aged 39.1 (8.2) years] were enrolled in a motionless suspension test while hanging in harness. Respiratory gas exchange values were analyzed to assess the pattern of breathing (EpInWel, respiratory elastic power) and cardiovascular parameters were monitored (BP, blood pressure). Four participants experienced HHS after 30.0 (7.6) minutes, with an early manifestation of loss of control of both a sustainable EpInWel and BP, starting after 10-12 minutes. Among the other participants, two different reactions were observed during suspension: (1) group G1 tolerated 32.7 (11.4) minutes of suspension by a favorable adaptation of the EpInWel and BP parameters and (2) group G2 showed significantly shorter time of suspension 24.0 (10.4) minutes with unfavorable increase in EpInWel and BP. Conclusions: Greater resistance to HHS occurs in people developing less marked fluctuations of both respiratory and cardiovascular reflex responses. Conversely, wider fluctuations both in control of EpInWel and BP were observed in the event of decreased suspension tolerance or in syncopal events.

The Elusive Path of Brain Tissue Oxygenation and Cerebral Perfusion in Harness Hang Syncope in Mountain Climbers.

Lanfranconi, Francesca, Luca Pollastri, Giovanni Corna, Manuela Bartesaghi, Massimiliano Novarina, Alessandra Ferri, and Giuseppe Andrea Miserocchi. The elusive path of brain tissue oxygenation and cerebral perfusion in harness hang syncope in mountain climbers. High Alt Med Biol. 18:363-371, 2017. AIM: Harness hang syncope (HHS) is a risk that specifically affects wide ranges of situations requiring safety harnesses in mountains. An irreversible orthostatic stasis could lead to death if a prompt rescue is not performed. We aimed at evaluating the risk of developing HHS and at identifying the characteristics related to the pathogenesis of HHS. RESULTS: Forty adults (aged 39.1 [8.2] years) were enrolled in a suspension test lasting about 28.7 (11.4) minutes. We measured cardiovascular parameters, and near infrared spectroscopy (NIRS) was used to assess cerebral hypoxia by changes in the concentration of oxyhemoglobin (Δ[HbO2]) and de-oxyhemoglobin (Δ[HHb]). In the four participants who developed HHS: (1) systolic and diastolic blood pressure showed ample oscillations with a final abrupt drop (∼30 mmHg); (2) Δ[HbO2] increased after 8-12 minutes of suspension and reached a plateau before HHS; and (3) Δ[HHb] decreased with a final abrupt increase before syncope. CONCLUSIONS: Participants who developed HHS failed to activate cardiovascular reflexes that usually safeguard O2 availability to match the metabolic needs of the brain tissue. Since cerebral hypoxia was detected as an early phenomenon by Δ[HbO2] and Δ[HHb] changes, NIRS measurement appears to be the most important parameter to monitor the onset of HHS.

Reappraisal of DLCO adjustment to interpret the adaptive response of the air-blood barrier to hypoxia.

DLCO measured in hypoxia must be corrected due to the higher affinity (increase in coefficient θ) of CO with Hb. We propose an adjustment accounting for individual changes in the equation relating DLCO to subcomponents Dm (membrane diffusive capacity) and Vc (lung capillary volume): 1/DLCO=1/Dm+1/θVc. We adjusted the individual DLCO measured in hypoxia (HA, 3269m) by interpolating the 1/DLCO to the sea level (SL) 1/θ value. Nineteen healthy subjects were studied at SL and HA. Based on the proposed adjustment, DLCO increased in HA in 53% of subjects, reflecting the increase in Dm that largely overruled the decrease in Vc. We hypothesize that a decrease in Vc (buffering microvascular filtration) and the increase in Dm (possibly resulting from a decrease in thickness of the air-blood barrier) represent the anti-edemagenic adaptation of the lung to hypoxia exposure. The efficiency of this adaptation varied among subjects as DLCO did not change in 31% of subjects and decreased in 16%.

Air blood barrier phenotype correlates with alveolo-capillary O2 equilibration in hypobaric hypoxia.

The O2 diffusion limitation across the air blood barrier (DO2 and subcomponents Dm and Vc) was evaluated in 17 healthy participants exposed to hypobaric hypoxia (HA, 3840m, PIO2 ∼90mmHg). A 10% decrease in alveolar volume (VA) in all participants suggested the development of sub-clinical interstitial lung edema. In >80% of participants DO2/VA increased, reflecting an individual strategy to cope with the hypoxia stimulus by remodulating Vc or Dm. Opposite changes in Dm/Vc ratio were observed and participants decreasing Vc showed reduced alveolar blood capillary transit time. The interplay between diffusion and perfusion (cardiac output) was estimated in order to investigate the individual adaptive response to hypoxia. It appears remarkable that despite individual differences in the adaptive response to HA, diffusion limitation did not exceed ∼11% of the alveolar-venous PO2 gradient, revealing an admirable functional design of the air-blood barrier to defend the O2 diffusion/perfusion function when facing hypobaric hypoxia corresponding to 50mmHg decreased PAO2.

Noninvasive evaluation of skeletal muscle oxidative metabolism after heart transplant.

PURPOSE: The main aim of the present study was to investigate skeletal muscle oxidative metabolism in heart transplant recipients (HTR) by noninvasive tools. METHODS: Twenty male HTR (age 50.4 +/- 2.6 yr; mean +/- SE) and 17 healthy untrained age-matched controls (CTRL) performed an incremental exercise (IE) and a series of constant-load (CLE) moderate-intensity exercise tests on a cycloergometer. The following variables were determined: heart rate (HR); breath-by-breath pulmonary O2 uptake (VO2); and skeletal muscle (vastus lateralis) oxygenation indices by continuous-wave near-infrared spectroscopy. Changes in concentration of deoxygenated hemoglobin (Hb) and myoglobin (Mb) (Delta[deoxy(Hb + Mb)]), expressed as a fraction of values obtained during a transient limb ischemia, were taken as an index of skeletal muscle O2 extraction. "Peak" values were determined at exhaustion during IE. Kinetics of adjustment of variables were determined during CLE. RESULTS: VO2peak, HRpeak, and Delta[deoxy(Hb + Mb)] peak were significantly lower in HTR than in CTRL (17.1 +/- 0.7 vs 34.0 +/- 1.9 mL.kg(-1).min(-1), 133.8 +/- 3.8 vs 173.0 +/- 4.8 bpm, and 0.42 +/- 0.03 vs 0.58 +/- 0.04, respectively). In HTR, Delta[deoxy(Hb + Mb)] increase at submaximal workloads was steeper than in CTRL, suggesting an impaired O2 delivery to skeletal muscles, whereas the lower Delta[deoxy(Hb + Mb)] peak values suggest an impaired capacity of O2 extraction at peak exercise. VO2 and HR kinetics during CLE were significantly slower in HTR than in CTRL, whereas, unexpectedly, no significant differences were found for Delta[deoxy(Hb+Mb)] kinetics (mean response time: 21.3 +/- 1.1 vs 20.2 +/- 1.2 s). CONCLUSION: The findings confirm the presence of both "central" (cardiovascular) and "peripheral" (at the skeletal muscle level) impairments to oxidative metabolism in HTR. The noninvasiveness of the measurements will allow for serial evaluation of the patients, in the presence and/or absence of rehabilitation programs.

Osteopathic Manual Treatment for Amyotrophic Lateral Sclerosis: A Feasibility Pilot Study.

BACKGROUND: Current interventions in amyotrophic lateral sclerosis (ALS) are focused on supporting quality of life (QoL) and easing pain with a multidisciplinary approach. OBJECTIVE: Primary aim of this pilot work assessed feasibility, safety, tolerability and satisfaction of osteopathic manual treatment (OMT) in 14 ALS outpatients. METHODS: Patients were randomized according to an initial single-blind design (12 weeks, T0-T1), in order to receive OMT (weekly for 4 weeks, and fortnightly for the following 8 weeks) versus usual-care (n=7 each group), followed by an OMT open period (T1-T2, once a week for 8 weeks, n=10). Secondary aims included blind osteopathic assessment of somatic dysfunctions (SD) for goal attainment scale (GAS) calculation, Brief Pain Inventory-short form and McGill QoL-16 items. RESULTS: OMT was demonstrated feasible and safe and patients displayed high satisfaction (T1-VAS=8.34 ± 0.46; T2-VAS=8.52 ± 0.60). Considering secondary aims no significant differences emerged. Finally, at study entry (T0), a cervico-dorsal SD was found in 78% of ALS patients versus 28% of healthy matched controls (p<0.01). CONCLUSION: OMT was found feasible, safe and satisfactory in ALS. The lack of secondary aim differences can be due to the limited sample size. OMT could be an interesting option to explore in ALS.

Inter-individual differences in control of alveolar capillary blood volume in exercise and hypoxia.

We compared by non-invasive technique the adaptive response of alveolar capillary network to edemagenic conditions (exercise and high altitude [HA, PIO2 107mmHg] in subjects with different resting sea level (SL) capillary blood volume (normalized to alveolar volume, Vc/Va): Group 1 (N=10, Vc/Va=16.1±6.8ml/L- mean±SD) and Group 2 (N=10, Vc/Va=25±7.7). In Group 1 Vc/Va remained unchanged in HA at rest and increased during exercise at SL (26.3±8.6) and HA (28.75±10.2); in Group 2 Vc/Va significantly decreased in HA (19±6) and did not increase in exercise at SL and HA. We hypothesize that Group2 exerts a tight control on Vc/Va being more exposed to the risk of lung edema due to inborn greater microvascular permeability. Conversely, Group 1 appears more resistant to lung edema given the large capillary recruitment in the most edemagenic condition. The 4-fold increase in frequency dependence of respiratory resistance in Group2 in HA stems for greater proneness for lung water perturbation compared to Group 1.

Near infrared spectroscopy (NIRS) as a new non-invasive tool to detect oxidative skeletal muscle impairment in children survived to acute lymphoblastic leukaemia.

BACKGROUND: Separating out the effects of cancer and treatment between central and peripheral components of the O2 delivery chain should be of interest to clinicians for longitudinal evaluation of potential functional impairment in order to set appropriate individually tailored training/rehabilitation programmes. We propose a non-invasive method (NIRS, near infrared spectroscopy) to be used in routine clinical practice to evaluate a potential impairment of skeletal muscle oxidative capacity during exercise in children previously diagnosed with acute lymphoblastic leukaemia (ALL). The purpose of this study was to evaluate the capacity of skeletal muscle to extract O2 in 10 children diagnosed with ALL, 1 year after the end of malignancy treatment, compared to a control group matched for gender and age (mean±SD = 7.8±1.5 and 7.3±1.4 years, respectively). METHODS AND FINDINGS: Participants underwent an incremental exercise test on a treadmill until exhaustion. Oxygen uptake ([Formula: see text]), heart rate (HR), and tissue oxygenation status (Δ[HHb]) of the vastus lateralis muscle evaluated by NIRS, were measured. The results showed that, in children with ALL, a significant linear regression was found by plotting [Formula: see text] vs Δ[HHb] both measured at peak of exercise. In children with ALL, the slope of the HR vs [Formula: see text] linear response (during sub-maximal and peak work rates) was negatively correlated with the peak value of Δ[HHb]. CONCLUSIONS: The present study proves that the NIRS technique allows us to identify large inter-individual differences in levels of impairment in muscle O2 extraction in children with ALL. The outcome of these findings is variable and may reflect either muscle atrophy due to lack of use or, in the most severe cases, an undiagnosed myopathy.