Validity and Reliability of Dynamic and Functional Balance Tests in People Aged 19-54: A Systematic Review.

Evaluating an impairment in an individual's capacity to maintain, achieve, or restore balance suggests a deficiency in postural control. For effective identification of individuals at risk for falls, balance assessment should exhibit reliability, validity, and ease of use. This systematic review concentrated on dynamic and functional balance assessment methods and their validity in healthy adults aged 19-54. The objective was to clarify the tools that health professionals can utilize to assess balance in this healthy population. Methods: A systematic literature search conducted in August 2019 yielded nine articles meeting predefined selection criteria. Inclusion criteria required studies featuring healthy adult participants aged 19-54, published in English, and focusing on dynamic and functional balance testing. Exclusion criteria excluded studies involving participants with chronic diseases or musculoskeletal disorders, systematic reviews, professional athletes, and those lacking specific participant age information. The quality of the studies was evaluated using a modified PEDro scale. Results: This review analyzed ten distinct postural balance tests. The Star Excursion Balance Test and Y-Balance Test exhibited moderate to high reliability, establishing them as dependable measures of dynamic balance. The Nintendo Wii Balance Board, Clever Balance Board, and Posturomed device also displayed excellent reliability for assessing dynamic postural balance. Comparing one-arm and two-arm functional reach tests, the one-arm reach test emerged as a more suitable option for evaluating dynamic balance among young adults. Moreover, an investigation comparing three dynamic balance tests (one-leg jump landing, Posturomed device, and stimulated forward fall) revealed a low correlation among these tests, indicating a measurement of different balance constructs. Discussion: In conclusion, the Y-Balance Test stands out as the most practical dynamic balance assessment for clinical use, characterized by a standardized protocol, good repeatability, affordability, and ease of application. The Nintendo Wii Balance Board also presents itself as a cost-effective and reliable tool for dynamic balance evaluation in clinical settings. It is crucial to recognize that these tests appraise discrete postural skills, preventing direct comparisons between test outcomes. This review equips healthcare professionals with valuable insights into optimal balance assessment methods for the healthy, 19 to 54 aged population. Levels of evidence: Level 3.

Altered Expiratory Flow Dynamics at Peak Exercise in Adult Men With Well-Controlled Type 1 Diabetes.

Type 1 diabetes may, in time, cause lung dysfunction including airflow limitation. We hypothesized that ventilatory flow morphology during a cardiopulmonary exercise test (CPET) would be altered in adult men with well-controlled type 1 diabetes. Thirteen men with type 1 diabetes [glycated hemoglobin A1c 59 (9) mmol/mol or 7.5 (0.8)%, duration of diabetes 12 (9) years, and age 33.9 (6.6) years] without diagnosed diabetes-related complications and 13 healthy male controls [age 37.2 (8.6) years] underwent CPET on a cycle ergometer (40 W increments every 3 min until volitional fatigue). We used a principal component analysis based method to quantify ventilatory flow dynamics throughout the CPET protocol. Last minute of each increment, peak exercise, and recovery were examined using linear mixed models, which accounted for relative peak oxygen uptake and minute ventilation. The type 1 diabetes participants had lower expiratory peak flow (P = 0.008) and attenuated slope from expiration onset to expiratory peak flow (P = 0.012) at peak exercise when compared with the healthy controls. Instead, during submaximal exercise and recovery, the type 1 diabetes participants possessed similar ventilatory flow dynamics to that of the healthy controls. In conclusion, men with relatively well-controlled type 1 diabetes and without clinical evidence of diabetes-related complications exhibited attenuated expiratory flow at peak exercise independently of peak oxygen uptake and minute ventilation. This study demonstrates that acute exercise reveals alterations in ventilatory function in men with type 1 diabetes but not until peak exercise.

Asthma, allergies and respiratory symptoms in different activity groups of swimmers exercising in swimming halls.

BACKGROUND: Respiratory symptoms are common in competitive swimmers. However, among these and in swimmers at other activity levels the swimming distance, the total spent time in swimming halls and their medical background varies. Our objectives were, first, to assess their medical histories and the associations with respiratory symptoms among swimmers in different activity groups and then second, to study the pulmonary function findings and related medications in competitive swimmers who exercise in swimming hall environments the most. METHODS: First, 1118 participants consisting of 133 competitive-, 734 fitness- and 251 occasional swimmers answered questionnaires concerning their medical background, their respiratory symptoms in connection to swimming distance and their amount of time spent in swimming halls. Secondly, in 130 competitive swimmers, pulmonary function was tested by spirometry and a specific questionnaire was used to assess respiratory symptoms, medical histories and prescribed medication. RESULTS: Respiratory symptoms were reported by 18% of the studied swimmers. Competitive swimmers had significantly more symptoms than fitness- and occasional swimmers. Naturally competitive swimmers swum more than 2000 m and stayed by the pool more than 90 min, longer than the other activity groups of swimmers. Spirometry testing showed airway obstruction in 15 swimmers, which was 12% of the 130 competitive swimmers. 21 of them, had physician-diagnosed asthma and 16 of these individuals had prescribed medication for it. CONCLUSIONS: Competitive swimmers had the highest swimming hall exposure and reported significantly more respiratory symptoms. A high prevalence of airway obstruction findings in competitive swimmers with asthma and allergies suggests a need for future recommendations for regular testing and special medical care for competitive swimmers.

Frequent physical activity is associated with reduced risk of severe diabetic retinopathy in type 1 diabetes.

AIMS: The aim of this study was to investigate whether leisure-time physical activity (LTPA) is associated with the development of severe diabetic retinopathy in individuals with type 1 diabetes. METHODS: Prospective observational analysis as part of the Finnish diabetic nephropathy (FinnDiane) Study with a mean follow-up time of 10.7 years was performed. A total of 1612 individuals with type 1 diabetes were recruited, and LTPA was assessed at baseline using a validated self-report questionnaire. Severe diabetic retinopathy was defined as the initiation of laser treatment due to severe nonproliferative, proliferative retinopathy or diabetic maculopathy (identified from the Care Register for Health Care). RESULTS: A total of 261 patients received laser treatment during the follow-up. Higher frequency of LTPA was associated with a lower incidence of severe diabetic retinopathy (p = 0.024), a finding that remained significant after adjustment for gender, duration, age at onset of diabetes, kidney function, BMI, triglycerides and systolic blood pressure. However, when HbA1c and smoking were added to the Cox regression model the association was no more significant. CONCLUSIONS: Frequent LTPA is associated with a lower incidence of severe diabetic retinopathy during the follow-up. The total amount or the other components of LTPA (intensity or duration of a single session) were not associated with severe diabetic retinopathy.

One-year unsupervised individualized exercise training intervention enhances cardiorespiratory fitness but not muscle deoxygenation or glycemic control in adults with type 1 diabetes.

Adaptations to long-term exercise training in type 1 diabetes are sparsely studied. We examined the effects of a 1-year individualized training intervention on cardiorespiratory fitness, exercise-induced active muscle deoxygenation, and glycemic control in adults with and without type 1 diabetes. Eight men with type 1 diabetes (T1D) and 8 healthy men (CON) matched for age, anthropometry, and peak pulmonary O2 uptake, completed a 1-year individualized training intervention in an unsupervised real-world setting. Before and after the intervention, the subjects performed a maximal incremental cycling test, during which alveolar gas exchange (volume turbine and mass spectrometry) and relative concentration changes in active leg muscle deoxygenated (Δ[HHb]) and total (Δ[tHb]) hemoglobin (near-infrared spectroscopy) were monitored. Peak O2 pulse, reflecting peak stroke volume, was calculated (peak pulmonary O2 uptake/peak heart rate). Glycemic control (glycosylated hemoglobin A1c (HbA1c)) was evaluated. Both T1D and CON averagely performed 1 resistance-training and 3-4 endurance-training sessions per week (∼1 h/session at ∼moderate intensity). Training increased peak pulmonary O2 uptake in T1D (p = 0.004) and CON (p = 0.045) (group × time p = 0.677). Peak O2 pulse also rose in T1D (p = 0.032) and CON (p = 0.018) (group × time p = 0.880). Training increased leg Δ[HHb] at peak exercise in CON (p = 0.039) but not in T1D (group × time p = 0.052), while no changes in leg Δ[tHb] at any work rate were observed in either group (p > 0.05). HbA1c retained unchanged in T1D (from 58 ± 10 to 59 ± 11 mmol/mol, p = 0.609). In conclusion, 1-year adherence to exercise training enhanced cardiorespiratory fitness similarly in T1D and CON but had no effect on active muscle deoxygenation or glycemic control in T1D.

Physical Activity Reduces Risk of Premature Mortality in Patients With Type 1 Diabetes With and Without Kidney Disease.

OBJECTIVE: The aims of the study were to assess how baseline leisure-time physical activity (LTPA) and its exercise components intensity, duration, and frequency are associated with all-cause and cardiovascular mortality in patients with type 1 diabetes 1) overall, 2) stratified by presence or absence of chronic kidney disease (CKD), and 3) stratified by sex. RESEARCH DESIGN AND METHODS: The study design was prospective and observational and included 2,639 patients with type 1 diabetes from the ongoing nationwide multicenter Finnish Diabetic Nephropathy (FinnDiane) Study. Mean follow-up time was 11.4 ± 3.5 years. LTPA was assessed by using a validated self-report questionnaire. Three hundred ten patients (11.7%) had CKD defined as an estimated glomerular filtration rate of ≤60 mL/min/1.73 m2. RESULTS: During follow-up, 270 deaths occurred. LTPA and all its components were associated with all-cause mortality, even after adjustment for the potential confounders sex, diabetic nephropathy, duration of diabetes, age at onset of diabetes, systolic blood pressure, triglycerides, BMI, and HbA1c. Only exercise intensity was associated with cardiovascular mortality after adjustment for the confounders. Of the patients with CKD, 127 died during follow-up. The total amount of LTPA and exercise frequency were independently associated with lower risk of all-cause mortality when adjusted for covariates. CONCLUSIONS: Exercise is associated with a lower risk of premature all-cause and cardiovascular mortality in patients with type 1 diabetes. This study also demonstrates that physical activity is associated with a lower risk of mortality in patients with type 1 diabetes and CKD.

The effects of health counseling and exercise training on self-rated health and well-being in middle-aged men: a randomized trial.

BACKGROUND: Few community-based lifestyle interventions have examined subjective well-being. We examined the effects of health counseling and exercise training on self-rated health (SRH), self-rated well-being (SRW) and depressive symptoms in middle-aged men at increased risk for cardiovascular disease (CVD) in a randomized controlled trial. METHODS: Men (N.=168) with at least two CVD risk factors engaging in leisure-time physical activity less than three times/week were randomized into: A) a group receiving single-session health counseling; B) a group receiving single-session health counseling and three months of weekly structured group exercise training; or C) a control group. We assessed SRH and SRW using visual analogue scales and depressive symptoms using a brief depression screener (the Patient Health Questionnaire-2, PHQ-2). RESULTS: Generalized estimating equation (GEE) models showed that, after 3 and 12 months, SRH (P=0.024) and SRW (P=0.014) improved across all groups. We found no differences between the groups (group by time effect, P=0.44 and P=0.80). The proportion of men with PHQ-2 scores ≥3 (positive depression screen) decreased in groups A (from 27% to 13%) and B (from 34% to 18%), but increased among controls (from 26% to 31%) (group by time effect, P=0.078). CONCLUSIONS: We found improvements in SRH and SRW, with a diminishing proportion of men screening positive for depression one year after a single health counseling session and a three-month exercise-training program. We detected, however, no statistically significant differences when comparing men who received health counseling or health counseling combined with exercise training to controls.

Frequent and intensive physical activity reduces risk of cardiovascular events in type 1 diabetes.

AIMS/HYPOTHESIS: Cardiovascular disease (CVD) is the most common cause of premature death and disability among patients with type 1 diabetes. Diabetic nephropathy accounts for the increased cardiovascular morbidity and mortality of these patients. We recently showed that the intensity of exercise predicts the incidence and progression of diabetic nephropathy in patients with type 1 diabetes. Little is known about the relationship between physical activity and CVD. Therefore, we studied how physical activity affects the risk of CVD events in patients with type 1 diabetes. METHODS: A 10 year follow-up study including 2180 type 1 diabetes patients from the nationwide multicentre Finnish Diabetic Nephropathy Study (FinnDiane). Leisure time physical activity (LTPA) was assessed by a previously validated self-report questionnaire. A CVD event was defined as a verified myocardial infarction, coronary procedure or stroke. Patients were analysed separately for the risk of developing a first ever CVD event and for the risk of a recurrent CVD event following a baseline event. RESULTS: A total of 206 patients had an incident CVD event during follow-up. A higher total LTPA and higher intensity, frequency and duration of activity were associated with a lower risk of incident CVD events. The observed association between exercise frequency and incident CVD remained significant when adjusted for classic risk factors. Exercise intensity also had a borderline effect on the recurrence-free time in patients with a major CVD event at baseline. CONCLUSIONS/INTERPRETATION: This study suggests that exercise, particularly high frequency and high intensity exercise, may reduce the risk of CVD events in patients with type 1 diabetes.

Altered cardiorespiratory response to exercise in overweight and obese women with polycystic ovary syndrome.

In polycystic ovary syndrome (PCOS), cardiovascular risk is increased. Peak O2 uptake (V˙O2peak) predicts the cardiovascular risk. We were the first to examine the contribution of systemic O2 delivery and arteriovenous O2 difference to V˙O2peak in overweight and obese women with PCOS. Fifteen overweight or obese PCOS women and 15 age-, anthropometry-, and physical activity-matched control women performed a maximal incremental cycling exercise test. Alveolar gas exchange (volume turbine and mass spectrometry), arterial O2 saturation (pulse oximetry), and cardiac output (CO) (impedance cardiography) were monitored. Hb concentration was determined. Arterial O2 content and arteriovenous O2 difference (C(a-v)O2) (Fick equation) were calculated. Insulin resistance was evaluated by homeostasis model assessment (HOMA-IR). PCOS women had lower V˙O2peak than controls (40 ± 6 vs. 46 ± 5 mL/min/kg fat-free mass [FFM], P = 0.011). Arterial O2 content was similarly maintained in the groups throughout the exercise test (P > 0.05). Linear regression analysis revealed a pronounced response of CO to increasing V˙O2 in PCOS women during the exercise test: A ∆CO/∆V˙O2 slope was steeper in PCOS women than in controls (ß = 5.84 vs. ß = 5.21, P = 0.004). Eventually, the groups attained similar peak CO and peak CO scaled to FFM (P > 0.05). Instead, C(a-v)O2 at peak exercise was lower in PCOS women than in controls (13.2 ± 1.6 vs. 14.8 ± 2.4 mL O2/100 mL blood, P = 0.044). HOMA-IR was similar in the groups (P > 0.05). The altered cardiorespiratory responses to exercise in overweight and obese PCOS women indicate that PCOS per se is associated with alterations in peripheral adjustments to exercise rather than with limitations of systemic O2 delivery.

Leisure-time physical activity and development and progression of diabetic nephropathy in type 1 diabetes: the FinnDiane Study.

AIMS/HYPOTHESIS: The aim of this study was to assess how physical activity predicts the development and progression of diabetic nephropathy in patients with type 1 diabetes. METHODS: This prospective study (follow-up time 6.4 ± 3.1 years) included 1,390 patients (48.5% men, mean age 37.0 ± 12.4 years, duration of diabetes 20.4 ± 12.3 years) participating in the nationwide multicentre Finnish Diabetic Nephropathy (FinnDiane) Study. Leisure-time physical activity (LTPA) was assessed using a validated self-report questionnaire. Renal status was defined according to standard clinical cut-off values for urinary AER. RESULTS: The total amount of LTPA was not associated with progression in renal status. For the intensity of LTPA, however, the 10 year cumulative progression rate was 24.0% (95% CI 18.8, 28.8), 13.5% (95% CI 10.3, 16.6) or 13.1% (95% CI 10.3%, 16.6%; p = 0.01) of the patients with low, moderate or high intensity LTPA. This pattern was similar to that for the development of de novo microalbuminuria. Corresponding progression rates for LTPA frequency of <1, 1-2 or >2 sessions/week was 24.7% (95% CI 18.3, 30.7), 14.7% (95% CI 10.2, 19.0) or 12.6% (95% CI 9.4, 15.7), respectively (p = 0.003). CONCLUSIONS/INTERPRETATION: This study demonstrates for the first time in a prospective setting the relationship between physical activity and the risk of diabetic nephropathy in patients with type 1 diabetes. The data suggest that physical activity, and in particular its intensity, may have an impact on the initiation and progression of diabetic nephropathy in type 1 diabetes.

Central and peripheral cardiovascular impairments limit VO(2peak) in type 1 diabetes.

PURPOSE: Cardiovascular risk, predicted by peak O2 uptake (VO(2peak)), is increased in type 1 diabetes. We examined the contribution of central and peripheral mechanisms to VO(2peak) in physically active adults with type 1 diabetes. METHODS: Seven men with type 1 diabetes and 10 healthy age-, anthropometry-, and physical activity-matched men performed incremental cycling exercise until volitional fatigue. Alveolar gas exchange (turbine and mass spectrometry), cardiac function and systemic vascular resistance (impedance cardiography), and local active leg muscle deoxygenation and blood flow (near infrared spectroscopy) were monitored. Arterial-venous O2 difference was calculated (Fick principle). Blood volume (BV) (carbon monoxide rebreathing method) and glycemic control (glycosylated hemoglobin) were determined. RESULTS: The group with diabetes had lower VO(2peak) than controls (47 ± 5 vs 56 ± 7 mL·min·kg fat-free mass, P < 0.05). At peak exercise, fat-free mass-adjusted stroke volume (SV) and cardiac output (CO) were lower and systemic vascular resistance was higher in the group with diabetes than those in controls (P < 0.05). Leg muscle blood flow was reduced independently of CO in the group with diabetes at peak exercise (P < 0.05), whereas arterial-venous O2 difference was similar in the groups throughout the exercise (P > 0.05). The group with diabetes had lower relative BV than controls (P < 0.01), and BV correlated positively with peak SV and peak CO (P < 0.001). In the group with diabetes, peak SV and peak CO correlated (P < 0.05) and peak leg muscle blood flow tended to correlate (P = 0.070) inversely with glycosylated hemoglobin. CONCLUSIONS: Both central and peripheral cardiovascular impairments limit VO(2peak) in physically active adults with type 1 diabetes. Importantly, central limitations, and probably peripheral limitations as well, are associated with glycemic control.

Ventilatory chemosensitivity, cerebral and muscle oxygenation, and total hemoglobin mass before and after a 72-day mt. Everest expedition.

BACKGROUND: We investigated the effects of chronic hypobaric hypoxic acclimatization, performed over the course of a 72-day self-supported Everest expedition, on ventilatory chemosensitivity, arterial saturation, and tissue oxygenation adaptation along with total hemoglobin mass (tHb-mass) in nine experienced climbers (age 37±6 years, [Formula: see text] 55±7 mL·kg(-1)·min(-1)). METHODS: Exercise-hypoxia tolerance was tested using a constant treadmill exercise of 5.5 km·h(-1) at 3.8% grade (mimicking exertion at altitude) with 3-min steps of progressive normobaric poikilocapnic hypoxia. Breath-by-breath ventilatory responses, Spo2, and cerebral (frontal cortex) and active muscle (vastus lateralis) oxygenation were measured throughout. Acute hypoxic ventilatory response (AHVR) was determined by linear regression slope of ventilation vs. Spo2. PRE and POST (<15 days) expedition, tHb-mass was measured using carbon monoxide-rebreathing. RESULTS: Post-expedition, exercise-hypoxia tolerance improved (11:32±3:57 to 16:30±2:09 min, p<0.01). AHVR was elevated (1.25±0.33 to 1.63±0.38 L·min(-1.)%(-1) Spo2, p<0.05). Spo2 decreased throughout exercise-hypoxia in both trials, but was preserved at higher values at 4800 m post-expedition. Cerebral oxygenation decreased progressively with increasing exercise-hypoxia in both trials, with a lower level of deoxyhemoglobin POST at 2400, 3500 and 4800 m. Muscle oxygenation also decreased throughout exercise-hypoxia, with similar patterns PRE and POST. No relationship was observed between the slope of AHVR and cerebral or muscle oxygenation either PRE or POST. Absolute tHb-mass response exhibited great individual variation with a nonsignificant 5.4% increasing trend post-expedition (975±154 g PRE and 1025±124 g POST, p=0.17). CONCLUSIONS: We conclude that adaptation to chronic hypoxia during a climbing expedition to Mt. Everest will increase hypoxic tolerance, AHVR, and cerebral but not muscle oxygenation, as measured during simulated acute hypoxia at sea level. However, tHb-mass did not increase significantly and improvement in cerebral oxygenation was not associated with the change in AHVR.

Alveolar gas exchange, oxygen delivery and tissue deoxygenation in men and women during incremental exercise.

We investigated whether leg and arm skeletal muscle, and cerebral deoxygenation, differ during incremental cycling exercise in men and women, and if women's lower capacity to deliver O2 affects tissue deoxygenation. Men (n=10) compared to women (n=10), had greater cardiac output, which with greater hemoglobin concentration produced greater absolute (QaO2) and body size-adjusted oxygen delivery (QaO2i) at peak exercise. Despite women's lower peak QaO2, their leg muscle deoxygenation was similar at a given work rate and QaO2, but less than in men at peak exercise (Δtissue saturation index -27.1 ± 13.2% vs. -11.8 ± 5.7%, P<0.01; Δ[deoxyhemoglobin] 15.03 ± 8.57 µM vs. 3.73 ± 3.98 µM, P<0.001). At peak exercise, oxygen uptake was associated both with QaO2 and leg muscle deoxygenation (both P<0.01). Arm muscle and cerebral deoxygenation did not differ between sexes at peak exercise. Thus, both high O2 delivery and severe active muscle deoxygenation are determinants of good exercise performance, and active muscle deoxygenation responses are regulated partly in a sex-specific manner with an influence of exercise capacity.

Low total haemoglobin mass, blood volume and aerobic capacity in men with type 1 diabetes.

Blood O2 carrying capacity affects aerobic capacity (VO2max). Patients with type 1 diabetes have a risk for anaemia along with renal impairment, and they often have low VO2max. We investigated whether total haemoglobin mass (tHb-mass) and blood volume (BV) differ in men with type 1 diabetes (T1D, n = 12) presently without complications and in healthy men (CON, n = 23) (age-, anthropometry-, physical activity-matched), to seek an explanation for low VO2max. We determined tHb-mass, BV, haemoglobin concentration ([Hb]), and VO2max in T1D and CON. With similar (mean ± SD) [Hb] (144 vs. 145 g l(-1)), T1D had lower tHb-mass (10.1 ± 1.4 vs. 11.0 ± 1.1 g kg(-1), P < 0.05), BV (76.8 ± 9.5 vs. 83.5 ± 8.3 ml kg(-1), P < 0.05) and VO2max (35.4 ± 4.8 vs. 44.9 ± 7.5 ml kg(-1) min(-1), P < 0.001) than CON. VO2max correlated with tHb-mass and BV both in T1D (r = 0.71, P < 0.01 and 0.67, P < 0.05, respectively) and CON (r = 0.54, P < 0.01 and 0.66, P < 0.001, respectively), but not with [Hb]. Linear regression slopes were shallower in T1D than CON both between VO2max and tHb-mass (2.4 and 3.6 ml kg(-1) min(-1) vs. g kg(-1), respectively) and VO2max and BV (0.3 and 0.6 ml kg(-1) min(-1) vs. g kg(-1), respectively), indicating that T1D were unable to reach similar VO2max than CON at a given tHb-mass and BV. In conclusion, low tHb-mass and BV partly explained low VO2max in T1D and may provide early and more sensitive markers of blood O2 carrying capacity than [Hb] alone.

Heart rate variability changes at 2400 m altitude predicts acute mountain sickness on further ascent at 3000-4300 m altitudes.

OBJECTIVE: If the body fails to acclimatize at high altitude, acute mountain sickness (AMS) may result. For the early detection of AMS, changes in cardiac autonomic function measured by heart rate variability (HRV) may be more sensitive than clinical symptoms alone. The purpose of this study was to ascertain if the changes in HRV during ascent are related to AMS. METHODS: We followed Lake Louise Score (LLS), arterial oxygen saturation at rest (R-SpO(2)) and exercise (Ex-SpO(2)) and HRV parameters daily in 36 different healthy climbers ascending from 2400 m to 6300 m altitudes during five different expeditions. RESULTS: After an ascent to 2400 m, root mean square successive differences, high-frequency power (HF(2 min)) of HRV were 17-51% and Ex-SpO(2) was 3% lower in those climbers who suffered from AMS at 3000 to 4300 m than in those only developing AMS later (≥5000 m) or not at all (all p < 0.01). At the altitude of 2400 m RMSSD(2 min) ≤ 30 ms and Ex-SpO(2) ≤ 91% both had 92% sensitivity for AMS if ascent continued without extra acclimatization days. CONCLUSIONS: Changes in supine HRV parameters at 2400 m were related to AMS at 3000-4300 m Thus, analyses of HRV could offer potential markers for identifying the climbers at risk for AMS.

Cardiovascular autonomic nervous system function and aerobic capacity in type 1 diabetes.

Impaired cardiovascular autonomic nervous system (ANS) function has been reported in type 1 diabetes (T1D) patients. ANS function, evaluated by heart rate variability (HRV), systolic blood pressure variability (SBPV), and baroreflex sensitivity (BRS), has been linked to aerobic capacity (VO(2peak)) in healthy subjects, but this relationship is unknown in T1D. We examined cardiovascular ANS function at rest and during function tests, and its relations to VO(2peak) in T1D individuals. Ten T1D patients (34 ± 7 years) and 11 healthy control (CON; 31 ± 6 years) age and leisure-time physical activity-matched men were studied. ANS function was recorded at rest and during active standing and handgrip. Determination of VO(2peak) was obtained with a graded cycle ergometer test. During ANS recordings SBPV, BRS, and resting HRV did not differ between groups, but alpha1 responses to maneuvers in detrended fluctuation analyses were smaller in T1D (active standing; 32%, handgrip; 20%, medians) than in CON (active standing; 71%, handgrip; 54%, p < 0.05). VO(2peak) was lower in T1D (36 ± 4 ml kg(-1) min(-1)) than in CON (45 ± 9 ml kg(-1) min(-1), p < 0.05). Resting HRV measures, RMSSD, HF, and SD1 correlated with VO(2peak) in CON (p < 0.05) and when analyzing groups together. These results suggest that T1D had lower VO(2peak), weaker HRV response to maneuvers, but not impaired cardiovascular ANS function at rest compared with CON. Resting parasympathetic cardiac activity correlated with VO(2peak) in CON but not in T1D. Detrended fluctuation analysis could be a sensitive detector of changes in cardiac ANS function in T1D.

Alveolar gas exchange and tissue oxygenation during incremental treadmill exercise, and their associations with blood O(2) carrying capacity.

The magnitude and timing of oxygenation responses in highly active leg muscle, less active arm muscle, and cerebral tissue, have not been studied with simultaneous alveolar gas exchange measurement during incremental treadmill exercise. Nor is it known, if blood O(2) carrying capacity affects the tissue-specific oxygenation responses. Thus, we investigated alveolar gas exchange and tissue (m. vastus lateralis, m. biceps brachii, cerebral cortex) oxygenation during incremental treadmill exercise until volitional fatigue, and their associations with blood O(2) carrying capacity in 22 healthy men. Alveolar gas exchange was measured, and near-infrared spectroscopy (NIRS) was used to monitor relative concentration changes in oxy- (Δ[O(2)Hb]), deoxy- (Δ[HHb]) and total hemoglobin (Δ[tHb]), and tissue saturation index (TSI). NIRS inflection points (NIP), reflecting changes in tissue-specific oxygenation, were determined and their coincidence with ventilatory thresholds [anaerobic threshold (AT), respiratory compensation point (RC); V-slope method] was examined. Blood O(2) carrying capacity [total hemoglobin mass (tHb-mass)] was determined with the CO-rebreathing method. In all tissues, NIPs coincided with AT, whereas RC was followed by NIPs. High tHb-mass associated with leg muscle deoxygenation at peak exercise (e.g., Δ[HHb] from baseline walking to peak exercise vs. tHb-mass: r = 0.64, p < 0.01), but not with arm muscle- or cerebral deoxygenation. In conclusion, regional tissue oxygenation was characterized by inflection points, and tissue oxygenation in relation to alveolar gas exchange during incremental treadmill exercise resembled previous findings made during incremental cycling. It was also found out, that O(2) delivery to less active m. biceps brachii may be limited by an accelerated increase in ventilation at high running intensities. In addition, high capacity for blood O(2) carrying was associated with a high level of m. vastus lateralis deoxygenation at peak exercise.

Acute mountain sickness, two cases and their treatment in the field.

OBJECTIVE: The number of lowland dwellers traveling at high altitudes has greatly increased in recent decades. Business travelers flying to La Paz or Lhasa are at risk of altitude illnesses, similarly to miners and soldiers transported to high altitudes. Traveling to high altitude requires adaptation and if this process fails due to too rapid an ascent rate or susceptibility of the climber, acute mountain sickness (AMS) may result. Doctors and nurses in travel clinics, health centers and occupational health care clinics may face patients asking advice on how to plan their trips or manage AMS, or the health care personnel may take part in a travel to high altitude environment. METHODS: Two patients, aged 29 and 47 years, who fulfilled the criteria for AMS were studied. The clinical findings and treatment in the field are described including the review of the current recommendations for prevention and treatment of AMS. RESULTS: Both patients developed a severe AMS due to too rapid ascent and their denial of the symptoms. CONCLUSIONS: Prevention is the safest and the most efficient method in the care concerning AMS. Realizing the risk of mountain sickness, active inquiry about the symptoms and correctly timed reaction to them, in other words interrupting the ascent or descending, help to reduce and even to prevent the development of serious problems.

Life events and change in leisure time physical activity: a systematic review.

The global epidemic of chronic non-communicable diseases is closely related to changes in lifestyle, including decreasing leisure time physical activity (PA). Physical inactivity is a major public health challenge. To respond to that challenge, it is essential to know which personal and environmental factors affect PA behaviour. Certain life events may be one contributing factor, by creating emotional distress and disrupting a person's daily routine. The aim was to examine the literature concerning the effects of life events on changes in PA. A systematic literature search was performed on studies that assessed at least one major change in life circumstances and a change in PA. To be included, studies had to assess PA at two timepoints at least (before and after the event). Diseases as life events were excluded from this review. Thirty-four articles met the inclusion criteria. The studies examined the following life-change events: transition to university; change in employment status; marital transitions and changes in relationships; pregnancy/having a child; experiencing harassment at work, violence or disaster; and moving into an institution. The studies reviewed showed statistically significant changes in leisure PA associated with certain life events. In men and women, transition to university, having a child, remarriage and mass urban disaster decreased PA levels, while retirement increased PA. In young women, beginning work, changing work conditions, changing from being single to cohabiting, getting married, pregnancy, divorce/separation and reduced income decreased PA. In contrast, starting a new personal relationship, returning to study and harassment at work increased PA. In middle-aged women, changing work conditions, reduced income, personal achievement and death of a spouse/partner increased PA, while experiencing violence and a family member being arrested or jailed decreased PA. In older women, moving into an institution and interpersonal loss decreased PA, while longer-term widowhood increased PA. In addition, experiencing multiple simultaneous life events decreased PA in men and women. Major life events have a strong effect on leisure PA behaviour. Consequently, people experiencing life events could be an important target group for PA promotion. More research is needed to examine the short- and long-term effects of different life events on PA, gender differences in the effects of life events and the specific determinants of PA change during life events.