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Alexei Wong and Arturo Figueroa

concluded that traditional high-intensity RET (70–80% 1-repetition maximum) appears to have no negative or positive effects on resting CAF, regardless of age ( Kingsley & Figueroa, 2016 ). In addition, a marked increase in sympathetic activity and blood pressure occurs during and in the first few minutes

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José Naranjo Orellana, Blanca de la Cruz Torres, Elena Sarabia Cachadiña, Moisés de Hoyo and Sergio Domínguez Cobo

Purpose:

The application of Poincaré-plot analysis to heart-rate variability (HRV) is a common method for the assessment of autonomic balance. However, results obtained from the indexes provided by this analysis tend to be difficult to interpret. In this study the authors aimed to prove the usefulness of 2 new indexes: the stress score (SS) and the sympathetic:parasympathetic ratio (S:PS ratio).

Methods:

25 professional Spanish soccer players from same team underwent 330 resting measurements of HRV. All subjects experienced 10 min of HRV monitoring through an R-R-interval recorder. The following parameters were calculated: (1) Poincaré-plot indexes: SD1 (transverse axis), which is proportional to parasympathetic activity; SD2 (longitudinal axis), which is inversely proportional to sympathetic activity; and the SD1:SD2 ratio; (2) time-domain parameters: standard deviation of R-R intervals (SDNN), root-mean-square differences of successive heartbeat intervals (rMSSD), and percentage of successive R-R-interval pairs differing in more than 50 ms in the entire recording divided by the total number of R-R intervals (pNN50); and (3) the proposed 2 new indexes: the SS and the S:PS ratio.

Results:

The study found a high negative correlation between the SS and SDNN (R 2 = .94). The S:PS ratio correlated inversely to rMSSD (R 2 = .95), SDNN (R 2 = .94), and pNN50 (R 2 = .74). The S:PS ratio showed a strong correlation with SD1 (R 2 = .95) and SS (r = .87, R 2 = .88).

Conclusions:

The application of the SS as sympathetic-activity index and the S:PS ratio as a representation of autonomic balance (SS:SD1) provides a better understanding of the Poincaré-plot method in HRV.

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Alexei Wong, Arturo Figueroa, Marcos A. Sanchez-Gonzalez, Won-Mok Son, Oksana Chernykh and Song-Young Park

low parasympathetic (vagal) and high sympathetic activity, leading to an increased sympathovagal balance (the relationship between sympathetic and vagal activity) ( Cohen et al., 2000 , 2001 ; Furlan et al., 2005 ; Martínez-Lavín, Hermosillo, Rosas, & Soto, 1998 ). HRV indexes in the frequency

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Fernando S. Lobo, Andreia C.C. Queiroz, Natan D. Silva Junior, Fabio L. Medina, Luiz A.R. Costa, Tais Tinucci and Claudia L.M. Forjaz

control sessions may seem odd at first, but it has already been reported, 23 , 25 and has been explained by the increase in peripheral sympathetic activity that occurs along time due to circadian rhythms when the experiments were conducted in the morning, and to the deactivation of cardiopulmonary reflex

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Kara N. Gange, Michael C. Kjellerson and Christiane J. Berdan

(mild heating) causes mild inflammation and accelerates the metabolic rate, whereas a 2–3°C increase (moderate heating) reduces muscle spasm, pain, and chronic inflammation and increases blood flow within the tissue. Vigorous heating (≥4°C increase) inhibits sympathetic activity and increases collagen

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), root mean square of successive differences (RMSSD) and mean EDA as indicators of parasympathetic and sympathetic activity were calculated from movement free 3 minute segments. Subjective perceived exertion was assessed by questionnaire. Results.— Subjectively perceived exertion (difference between

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Jose A. Rodríguez-Marroyo, José G. Villa, Raúl Pernía and Carl Foster

also be caused by the reduction in sympathetic activity. 17 It might be expected that other factors contribute to the performance decrement. In this sense, oxidative and muscular damage has been identified across the Vuelta in cyclists that performed similar exercise intensities to those in this study

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Ben T. Stephenson, Christof A. Leicht, Keith Tolfrey and Victoria L. Goosey-Tolfrey

; 12 ( suppl 2 ): S2-87 – S2-94 . PubMed ID: 27834554 doi:10.1123/ijspp.2016-0404 10.1123/ijspp.2016-0404 29. Leicht CA , Paulson TAW , Goosey-Tolfrey VL , Bishop NC . Salivary alpha amylase not chromogranin A reflects sympathetic activity: exercise responses in elite male wheelchair

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Jaqueline P. Batista, Igor M. Mariano, Tállita C.F. Souza, Juliene G. Costa, Jéssica S. Giolo, Nádia C. Cheik, Foued S. Espindola, Sarah Everman and Guilherme M. Puga

sympathetic activity, baroreflex activity, and reduced cardiac output, or a decrease in systolic volume ( Halliwill, Buck, Lacewell, & Romero, 2013 ). Previous studies have shown that different exercises mode, duration and intensity, impact the magnitude and duration of PEH ( Anunciação & Polito, 2011

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Pedro L. Valenzuela, Guillermo Sánchez-Martínez, Elaia Torrontegi, Zigor Montalvo, Alejandro Lucia and Pedro de la Villa

D , Calmels P , Pichot V , Bethoux F , Roche F . Effects of compression stockings on sympathetic activity and heart rate variability in individuals with spinal cord injury . J Spinal Cord Med . 2012 ; 35 ( 2 ): 81 – 88 . PubMed ID: 22333734 doi:10.1179/2045772311Y.0000000054