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Autonomic nervous system changes during 21 half-marathon in 21 days: a case report
No full textIntroduction. Heart Rate Variability (HRV) has recently been proposed to detect the Autonomic Nervous System (ANS) adaptations to endurance training and performance. However, the effect of training on HRV indexes remains inconclusive. To assess whether the morning short-term HR recording in clinostatic position may be useful in evaluating the training-induced autonomic changes, detecting fatigue and predict the possible overtraining.
Methods. A 42 yrs old woman (height 162 cm; body mass 52 kg; fat mass 16,6%; VO2max 45,9 mlkg-1min-1), voluntarily perform 21 half-marathons in 21 days, one half-marathon each day. Every day before the half marathon, the subject performed RR series were recorded after awakening supine (10 min) positions. The HRV parameters considered were LogRMSSD, LogpNN50, LogHF, [0.15-0.40 Hz]. Frequencies: absolute powers, LF/HF ratio, and the non-linear index Sample Entropy (SampEn) and Detrended Fluctuations (1). In addition the velocity (kmh-1) of each half-marathon was reported.
Results. ANS changed in relation to half-marathon performances. The mean velocity of all half-marathons was 11.00.5 kmh-1. A positively correlation between RMSSD (r=0.63), pNN50 (r=0.53), HF (r=0.57), SampEn (r=0.42) index and the number of half-marathon (p<0.05), while negative correlation in LF/HF ratio (r=-0.57) and DFA1 (r=-0.57) (p=ns), was found. In particular, HRV indexes of cardiac vagal tone comparing the 21th half-marathon with the 1st tended to increase (LogRMSSD: 2.18 vs 1.95, +11.8%; LogpNN50: 1.72 vs 1.65, + 4.2%; LogHF: 3.65 vs 3.20, +14.1%; SampEn: 1.60 vs 1.42, +12.7%). The cardiac sympathovagal balance tended to decrease (LF/HF ratio: 1.19 vs 5.74, -79.3%; 1: 0.92 vs 1.30, -29.3%). A positively correlation between RMSSD (r=0.45, p<0.05), pNN50 (r=0.58, p<0.05), HF (r=0.52, p<0.05), SampEn (r=0.45, p=0.057) index and the velocity during half-marathon, while negative correlations in LF/HF ratio (-0.57, p<0.05) and 1 (-0.57, p<0.05) was found. Especially, the min – max velocity during all half-marathons was respectively 10.1 – 11.6 kmh-1, and in this range of velocities there is a changing in HRV indexes: RMSSD (+41.9%), pNN50 (+52.1%), HF (+78.0%), SampEN (+100.0%), LF/HF (+707.6%), 1 (+70.7%).
Conclusions.
A large amount of exercise is related to parasympatic modulation. In fact, during the 21 half-marathons cardiac autonomic balance shift to sympathetic over parasympathetic drive. HRV may be useful in detecting the autonomic changes induced by endurance performance. This type of changes could be determined by fatigue or a result of possible overtraining
Cardiorespiratory Improvements Achieved by American College of Sports Medicine's Exercise Prescription Implemented on a Mobile App
Get PDFBackground: Strong evidence shows that an increase in cardiorespiratory fitness (CRF) and physical activity (PA) reduces
cardiovascular disease risk.
Objective: To test whether a scientifically endorsed program to increase CRF and PA, implemented on an easy-to-use,
always-accessible mobile app would be effective in improving CRF.
Methods: Of 63 healthy volunteers participating, 18 tested the user interface of the Cardio-Fitness App (CF-App); and 45
underwent a 2-week intervention period, of whom 33 eventually concluded it. These were assigned into three groups. The
Step-based App (Step-App) group (n=8), followed 10,000 steps/day prescription, the CF-App group (n=13), and the Supervised
Cardio-Fitness (Super-CF) group (n=12), both followed a heart rate (HR)-based program according to American College of Sports
Medicine (ACSM) guidelines, but either implemented on the app, or at the gym, respectively. Participants were tested for CRF,
PA, resting systolic and diastolic blood pressures (SBP, DBP), resting, exercise, and recovery HR.
Results: CRF increased in all groups (+4.9%; P<.001). SBP decreased in all groups (-2.6 mm Hg; P=.03). DBP decrease was
higher in the Super-CF group (-3.5 mm Hg) than in the Step-App group (-2.1 mm Hg; P<.001). Posttest exercise HR decreased
in all groups (-3.4 bpm; P=.02). Posttest recovery HR was lower in the Super-CF group (-10.1 bpm) than in the other two groups
(CF-App: -4.9 bpm, Step-App: -3.3 bpm; P<.001). The CF-App group, however, achieved these improvements with more training
heart beats (P<.01).
Conclusions: A 10,000 steps/day target-based app improved CRF similar to an ACSM guideline-based program whether it was
implemented on a mobile app or in supervised gym sessions.
(JMIR Mhealth Uhealth 2016;4(2):e77) doi:10.2196/mhealth.551
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Risposte fisiologiche e psicologiche a seguito di 21 mezze maratone consecutive: un caso studio
No full textVariations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Effects of 21 half-marathon in 21 days on autonomic nervous system and psychological parameters : a case report
No full textAim. Heart Rate Variability (HRV) measurement is a non-invasive method used to investigate the Autonomic Nervous System (ANS) responsiveness in healthy as well as patients. Even if consequences of a short term training period on ANS is well ancknoledged, the long-term (>15 days) effect of repeated submaximal exercise remains elusive. We investigated the cardiac ANS adaptation to 21 consecutive half-marathons and its possible relationships with psychological fatigue.
Methods. A 42 yrs old woman (BMI: 19.8; VO2max: 45,9 ml/kg/min), voluntarily performed 21 half-marathons in 21 consecutive days. Every morning, after awakening, heart rate (HR) for 10 min on a beat-to-beat basis (RR series) in supine position. RR series spectral powers, indexes of vagal (HFnu; 0.15-0.40 Hz), mixed para- and sympathetic tone (LFnu; 0.04-0.15 Hz) and sympatho-vagal balance (LF/HF ratio), were derived. A 32-item profile of mood states (POMS) questionnaire and Session RPE (mins x RPE 10 points scale) were daily collected.
Results. Running time did not change significantly (1h54’55’’± 4’55’’; p=0.44, r=-0.18). Number of consecutive running days (NcRD) negatively linearly correlated with HR rest (p<0.001, r=-0.7) and LogLF/HF (p<0.01, r=0.64), and positively with LogHF Power (n.u.) (p<0.01, r=0.62). NcRD did not linearly correlated with LogLF Power (n.u.) (p<0.01, r2=0.55). NcRD negatively linearly correlated with the Energy Index (EI) (p<0.0001, r=-0.87). NcRD positively correlated with session-RPE (p<0.01, r=0.62), whose scores ranged between 0.3 and 5. A positive correlation between LogLF/HF ratio and EI (p<0.01, r=0.61) and a negative correlation between LogHF Power (n.u.) (p<0.01, r=-0.61) were found. There were no correlations between EI (vigor-fatigue) and LogLF Power (n.u.).
Conclusions. Twenty-one consecutive half-marathons at sub-maximal intensity led to a continuous improvement of cardio-vagal control and sympatho-vagal balance, without a clear plateau. This suggests a training effect, that could be extended further. The EI increase seemed to reveal an accumulation of psychological fatigue, probably due to lack of recovery days and monotony of training. Therefore, long-term daily repetitions of sub-maximal exercise seems to improve cardio-vagal tone, but to induce also a psychological fatigue accumulation, which could demotivate the atlete in continuing the training.
References
1. Aubert AE et al.(2003) Heart Rate Varibility in Athletes. Sports Med.;33(12):889-919
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