IJCS | Volume 32, Nº4, July/August 2019

407 70. Dobbs WC, Fedewa MV, MacDonald HV, Holmes CJ, Cicone ZS, Plews DJ, et al. The accuracy of acquiring heart rate variability from portable devices: a systematic review and meta-analysis. Sports Med. 2019;49(3):417-35. 71. Silva BM, Vianna LC, Oliveira RB, Ricardo DR, Araujo CG. Similar cardiac vagal withdrawal at the onset of arm and leg dynamic exercise. Eur J Appl Physiol. 2008;102(6):695-701. 72. Nobrega AC, Araujo CG. Heart rate transient at the onset of active and passive dynamic exercise. Med Sci Sports Exerc. 1993;25(1):37-41. 73. Araujo CG, Nobrega AC, Castro CL. Heart rate responses to deep breathing and 4-seconds of exercise before and after pharmacological blockade with atropine and propranolol. Clin Auton Res. 1992;2(1):35-40. 74. Araújo CG, Nóbrega AC, Castro CL. Vagal activity: effect of age, sex and physical activity pattern. Braz J Med Biol Res. 1989;22(7):909-11. 75. Almeida MB, Ricardo DR, Araújo CGS. Heart rate variability in a truly maximum exercise testing. Rev SOCERJ. 2005;18(6):534-41. 76. Araújo CG, Castro CLB, Franca JF, Ramos PS. 4-second exercise test: reference values for ages 18-81 years. Arq Bras Cardiol. 2015;104(5):366-74. 77. AlmeidaMB, RicardoDR, AraújoCGS. Validation of the 4-SecondExercise test in the orthostatic position. Arq Bras Cardiol. 2004;83(2):155-9. 78. Pimentel AS, Alves ES, Alvim RO, Nunes RT, Costa CMA, Lovisi JCM, et al. Polar S810 as an alternative resource to the use of the electrocardiogram in the 4-second exercise test. Arq Bras Cardiol. 2010;94(5):580-4. 79. Silva B, Silva B, Wichi R, Oliveira J, Almeida M. Cardio-frequency meter does not replace EKG for orthostatic 4-second exercise test. Rev Bras Cardiol. 2012;25(5):377-83. Almeida et al. HR monitors and apps in exercise Int J Cardiovasc Sci. 2019;32(4):396-407 Review Article This is an open-access article distributed under the terms of the Creative Commons Attribution License