Cardiovascular responses during rest-exercise and exercise-exercise transients

If indeed vagal withdrawal determines the rapid response to exercise (phase I), the a large reduction, if not complete suppression, of phase I should be found, when an exercise transient starts from a previous lower steady state exercise rather than from rest. On 15 healthy young subjects we measured beat-by-beat cardiac output (Q̇, Modelflow from Portapres data) and heart rate (fH, ECG) during these cycle ergometer exercise transients: 0–50 W (transient from rest, RT) and 50–100W (transient from exercise, ET). A double exponential was used to compute amplitudes and time constants of phase I and II (A1 and A2; T1 and T2). At steady state, fH was 87.510.4, 109.312.0, and 139.617.1bpm, and Q̇ was 7.31.5, 12.61.6, and 16,11,9L/min, at rest, 50W and 100W, respectively. In RT, A1 and A2 for fH were 11.78.6 and 11.34.7bpm; the corresponding T1 and T2 were 1.61.9 and 14.421.3s. For Q̇, we had: A1=4.01.8L/min, A2=1.51.4L/min, T1=3.21.8s, T2=11.312.2s. In ET, the double exponential model provided preposterous A1 and T1 values and extremely high T2 values (>100s). Subsequent use of a mono exponential model provided, for fH, A=29.78.9bpm and T=7.74.9s, and for Q̇, A=3.58.6L/min, and T=7.05.7s. The A and T in ET did not differ from the A2 and T2 of RT. We conclude that a single exponential model is more adequate to describe ET and this single exponential corresponds to the second exponential of RT. Our results are compatible with the vagal withdrawal hypothesis

LIFESTYLE ASSESSMENT AND IMPROVEMENT WITH FOCUS ON LEISURE TIME PHYSICAL ACTIVITY AMONG UNIVERSITY STUDENTS: THE #STUDIOXLAVITA PROJECT

INTRODUCTION: Sedentariness, smoking, alcohol abuse and unbalanced feeding are harmful for health, leading to chronic diseases and increasing mortality rate. For young adults, University is a new social and cultural context: parents’ imprinting could be easily altered, new lifestyles take shape and personal choices emerge. Intervention programmes to advance awareness on harmful lifestyle and promote healthy habits are essential. The #studioxlavita project, launched in 2016 by the University of Brescia with these purposes, investigated students’ lifestyle, with special emphasis on physical activity . METHODS: We developed two consecutive facultative surveys, of 15 <1st level> and 52 items <2nd level>, addressed to all the University’s students. Questions were about leisure time physical activity , use of fitness technology, relationship with friends, classmates and parents, feed, physical appearance, body self-perception, physical and mental health, use of certain substances or products , night-time rest and beliefs concerning healthy behaviours. In the 2nd level survey we also adopted the Kessler Psychological Distress Scale and the short form of the International Physical Activity Questionnaire to estimate the amount of PA carried out in the last 7 days. Students who filled in both questionnaires received a personal report including the aggregate data analysis, a comparison with other investigations and indications about healthy habits, according to recommendations and guidelines. RESULTS: 3,436 out of 15,688 students filled in the1st level survey. Of them, 778 accepted to participate in the 2nd level survey, and 456 completed it. 1st level survey revealed that 72% of the students practised LTPA <45% regularly and 27% occasionally>. LTPA is largely performed <44% of the student> in non-competitive form, with recreational and/or health purposes. According to IPAQ-SF categorical score, 24%, 34% and 42% of the students performed low, moderate and high levels of PA, respectively. In 2st level survey, 76% of the students wished to practise more PA; 42% would participate in practical sport courses. CONCLUSION: University is an ideal setting for promoting lifestyle change among a captive audience. Intervention programs to increment PA are acclaimed by students. The students from University of Brescia reported higher LTPA practice than the national average people between 18 and 34 years <47%, data from Italian National Institute of Statistics, 2015>, although this parameter was assessed with different methods

EFFECTS OF PHYSICAL ACTIVITY PROMOTION AMONG UNIVERSITY STUDENTS: THE #STUDIOXLAVITA PROJECT

INTRODUCTION: Sedentariness is a major health problem in our time and physical activity promotion is an imperative commitment for healthcare systems. Recommendations from WHO indicate a minimum of 150 minutes of moderate intensity aerobic exercise as weekly standard for adults. Strategies to increment PA practice are implemented in different settings, such as house care, school, University and workplace. The project #studioxlavita <#SXLV> was launched by the University of Brescia in 2016 with the aim of collecting data about undergraduates lifestyle and encourage healthy behaviours. In particular we focused on PA assessment and promotion in a Universitybased setting. METHODS: Two consecutive surveys were sent to all students . Q0 included the short form of the International Physical Activity Questionnaire , the Kessler Psychological Distress Scale and additional questions on several lifestyle aspects. Among responders, we selected 40 students who agreed to take part in one of the following 15-week practical sport courses: ultimate frisbee, muscle strengthening and dance fitness. Before and after being engaged in practical sport courses, students underwent cardiopulmonary exercise test and skinfold thickness measurements, in order to assess peak oxygen consumption and percent body fat . Finally, to assess possible lifestyle changes, we sent them additional surveys at the end of the practical sport courses and 30 days after . Paired t-test was used to analyse significant differences. RESULTS: 27 students <16 female, 11 male; age: 22.7±3.7> concluded sport activity courses and filled in Q1. Of them, 20 completed also Q2. Overall courses attendance was 57%. At T1 , normalized Q̇O2peak increased with respect to T0 <37.0±6.9 vs 35.2±7.4 ml/min/Kg, p=0.03>. Conversely, percent body fat decreased <16.5±6.4 vs 18.3±7.5, p=0.01>. In Q1, 20 students declared to have a more active lifestyle since the beginning of the courses. In Q2, IPAQ-SF-derived total weekly energy expenditure was higher than in Q0, although not significant <5,839 ±7,035 MET*min vs 2,770±2,457 MET*min, p=0.1>. Q2 showed a reduced K6 scale score with respect to Q0 <13.8±4.6 vs 15.8±4.9, p=0.03>. CONCLUSION: With the sport activity courses established in #SXLV we gave students the opportunity to comply with WHO recommendations. After courses, they appeared to practice more PA, have a higher maximal aerobic capacity, a lower percent body fat and a lower grade of psychological distress than before courses. Simple activities as those proposed by #SXLV are sufficient to reduce sedentariness and improve the quality of life of student

Circulating adrenomedullin estimates survival and reversibility of organ failure in sepsis: the prospective observational multinational Adrenomedullin and Outcome in Sepsis and Septic Shock-1 (AdrenOSS-1) study

Background: Adrenomedullin (ADM) regulates vascular tone and endothelial permeability during sepsis. Levels of circulating biologically active ADM (bio-ADM) show an inverse relationship with blood pressure and a direct relationship with vasopressor requirement. In the present prospective observational multinational Adrenomedullin and Outcome in Sepsis and Septic Shock 1 (, AdrenOSS-1) study, we assessed relationships between circulating bio-ADM during the initial intensive care unit (ICU) stay and short-term outcome in order to eventually design a biomarker-guided randomized controlled trial. Methods: AdrenOSS-1 was a prospective observational multinational study. The primary outcome was 28-day mortality. Secondary outcomes included organ failure as defined by Sequential Organ Failure Assessment (SOFA) score, organ support with focus on vasopressor/inotropic use, and need for renal replacement therapy. AdrenOSS-1 included 583 patients admitted to the ICU with sepsis or septic shock. Results: Circulating bio-ADM levels were measured upon admission and at day 2. Median bio-ADM concentration upon admission was 80.5 pg/ml [IQR 41.5-148.1 pg/ml]. Initial SOFA score was 7 [IQR 5-10], and 28-day mortality was 22%. We found marked associations between bio-ADM upon admission and 28-day mortality (unadjusted standardized HR 2.3 [CI 1.9-2.9]; adjusted HR 1.6 [CI 1.1-2.5]) and between bio-ADM levels and SOFA score (p < 0.0001). Need of vasopressor/inotrope, renal replacement therapy, and positive fluid balance were more prevalent in patients with a bio-ADM > 70 pg/ml upon admission than in those with bio-ADM ≤ 70 pg/ml. In patients with bio-ADM > 70 pg/ml upon admission, decrease in bio-ADM below 70 pg/ml at day 2 was associated with recovery of organ function at day 7 and better 28-day outcome (9.5% mortality). By contrast, persistently elevated bio-ADM at day 2 was associated with prolonged organ dysfunction and high 28-day mortality (38.1% mortality, HR 4.9, 95% CI 2.5-9.8). Conclusions: AdrenOSS-1 shows that early levels and rapid changes in bio-ADM estimate short-term outcome in sepsis and septic shock. These data are the backbone of the design of the biomarker-guided AdrenOSS-2 trial. Trial registration: ClinicalTrials.gov, NCT02393781. Registered on March 19, 2015

Cognitive Reserve and the Prevention of Dementia: the Role of Physical and Cognitive Activities

Purpose of Review: The article discusses the two most significant modifiable risk factors for dementia, namely, physical inactivity and lack of stimulating cognitive activity, and their effects on developing cognitive reserve. Recent Findings: Both of these leisure-time activities were associated with significant reductions in the risk of dementia in longitudinal studies. In addition, physical activity, particularly aerobic exercise, is associated with less age-related gray and white matter loss and with less neurotoxic factors. On the other hand, cognitive training studies suggest that training for executive functions (e.g., working memory) improves prefrontal network efficiency, which provides support to brain functioning in the face of cognitive decline. Summary: While physical activity preserves neuronal structural integrity and brain volume (hardware), cognitive activity strengthens the functioning and plasticity of neural circuits (software), thus supporting cognitive reserve in different ways. Future research should examine whether lifestyle interventions incorporating these two domains can reduce incident dementia

Physiological and anthropometric determinants of critical power, W ′ and the reconstitution of W ′ in trained and untrained male cyclists

From Springer Nature via Jisc Publications RouterHistory: received 2020-01-17, accepted 2020-07-31, registration 2020-08-01, pub-electronic 2020-08-09, online 2020-08-09, pub-print 2020-11Publication status: PublishedAbstract: Purpose: This study examined the relationship of physiological and anthropometric characteristics with parameters of the critical power (CP) model, and in particular the reconstitution of W′ following successive bouts of maximal exercise, amongst trained and untrained cyclists. Methods: Twenty male adults (trained nine; untrained 11; age 39 ± 15 year; mass 74.7 ± 8.7 kg; V̇O2max 58.0 ± 8.7 mL kg−1 min−1) completed three incremental ramps (20 W min−1) to exhaustion interspersed with 2-min recoveries. Pearson’s correlation coefficients were used to assess relationships for W′ reconstitution after the first recovery (W′rec1), the delta in W′ reconstituted between recoveries (∆W′rec), CP and W′. Results: CP was strongly related to V̇O2max for both trained (r = 0.82) and untrained participants (r = 0.71), whereas W′ was related to V̇O2max when both groups were considered together (r = 0.54). W′rec1 was strongly related to V̇O2max for the trained (r = 0.81) but not untrained (r = 0.18); similarly, ∆W′rec was strongly related to V̇O2max (r = − 0.85) and CP (r = − 0.71) in the trained group only. Conclusions: Notable physiological relationships between parameters of aerobic fitness and the measurements of W′ reconstitution were observed, which differed among groups. The amount of W′ reconstitution and the maintenance of W′ reconstitution that occurred with repeated bouts of maximal exercise were found to be related to key measures of aerobic fitness such as CP and V̇O2max. This data demonstrates that trained cyclists wishing to improve their rate of W′ reconstitution following repeated efforts should focus training on improving key aspects of aerobic fitness such as V̇O2max and CP

A Photonic Probe for Antenna Measurements

The paper describes the design and the numerical analysis of a new dielectric probe (DP) for non-invasive near field antenna measurements. The probe consists of a Lithium Niobate (LiNb03) substrate with a Mach-Zehnder (MZ) interferometer in push-pull (PP) configuration integrated in, and an optimized short dipole antenna printed on its surface. The strong electro-optic effect of LiNb03, in combination with the PP behaviour of the MZ interferometer, allows the amplitude modulation of an optical carrier by the external electric field incident on the probe. Moreover, the short dipole antenna guarantees effective selectivity towards the incident field polarization. The numerical analysis estimates a nearly flat frequency response in the band [1-10] GHz and a minimum detectable signal of a 8.8 mV/m √Hz

Single-breath oxygen dilution for the measurement of total lung capacity: Technical description and preliminary results in healthy subjects

Objective. Total lung capacity (TLC) assessment outside of a research laboratory is challenging. We describe a novel method for measuring TLC that is both simple and based only on portable equipment, and report preliminary data in healthy subjects. Approach. We developed an open circuit system to administer a known amount of oxygen to a subject in a single maximal inspiratory maneuver. Oxygen fraction, expired and inspired flows were continuously monitored to allow a precise computation of the mass balance. Values of TLC and functional residual capacity (FRC) were compared with standard methods (body plethysmography and multiple-breath helium dilution). Twenty healthy subjects participated to the study, eleven of which performed the maneuver twice to assess test-retest reliability. Main results. There was high agreement in TLC between the proposed method and the two standard methods (R 2 > 0.98, bias not different from 0, and 95% limits of agreements 0.99 and no bias). Results were similar for FRC, with a slightly higher variability due its sensitivity to changes in posture or breathing pattern. Significance. Single-breath oxygen dilution is accurate and reliable in assessing TLC and FRC in healthy subjects. The technique is appealing for time- or resource-limited settings, such as field physiological research expeditions or mass screenings