... Among the 101 experimental studies, the majority involved a single exposure to caffeine among adults and monitoring heart rate at various times thereafter. Among those, 15 reported an increase in heart rate following ingestion of a single dose (130e560 mg) of caffeine (Astorino et al., 2013;Bunsawat et al., 2015;Buscemi et al., 2009Buscemi et al., , 2011Del Coso et al., 2012;Grasser et al., 2014Grasser et al., , 2015Lane et al., 1998Lane et al., , 2002Miles-Chan et al., 2015;Passmore et al., 1987;Peveler et al., 2016;Stadheim et al., 2013;Steinke et al., 2009;Stubbs and Macdonald, 1995), 19 reported a decrease after 80e350 mg (Addicott et al., 2009;Arciero and Ormsbee, 2009;Awaad et al., 2011;Berry et al., 2003;Domotor et al., 2015;Hajsadeghi et al., 2016;Hartley et al., 2004;Lovallo et al., 1996;Molnar and Somberg, 2015a;Papaioannou et al., 2006;Pincomb et al., 1996;Sung et al., 1994Sung et al., , 1995Temple et al., 2010;Turley and Gerst, 2006;Turley et al., 2007Turley et al., , 2008Vlachopoulos et al., 2003a;Waring et al., 2003) -including all four studies that involved children (Temple et al., 2010;Turley and Gerst, 2006;Turley et al., 2007Turley et al., , 2008) -while the majority (55) reported no significant change in heart rate after 250e570 mg Ammon et al., 1983;Arciero et al., 1998;Astorino et al., 2013;Bak and Grobbee, 1991;Barry et al., 2005;Baum and Weiss, 2001;Blaha et al., 2007;Bonnet et al., 2005;Bortolotti et al., 2014;Brothers et al., 2016;Burr et al., 1989;Buscemi et al., 2010;Chen and Parrish, 2009;Childs and de Wit, 2006;Daniels et al., 1998;Doerner et al., 2015;Donnerstein et al., 1998;Duncan et al., 2013;Engels et al., 1999;Fernandez-Elias et al., 2015;Garcia et al., 2016;Giacomin et al., 2008;Hajsadeghi et al., 2016;Hodgson et al., 1999;Hoffman et al., 2006;Humayun et al., 1997;Kennedy et al., 2008;Kurtz et al., 2013;Lemery et al., 2015;Miles-Chan et al., 2015;Molnar and Somberg, 2015a,b;Mosqueda-Garcia et al., 1990;Nash et al., 2002;Noguchi et al., 2015;Nussberger et al., 1990;Paton et al., 2015;Pettersen et al., 2014;Peveler et al., 2016;Phan and Shah, 2014;Ragsdale et al., 2010;Rashti et al., 2009;Scott et al., 2015;Shah et al., 2016;Shechter et al., 2011;Sondermeijer et al., 2002;Souza et al., 2014;Sudano et al., 2005;Tse et al., 2009;Turley et al., 2007;Umemura et al., 2006;Vlachopoulos et al., 2003bVlachopoulos et al., , 2006Yeragani et al., 2005;Zimmermann-Viehoff et al., 2016). In some cases, the effect on heart rate from caffeine consumption at similar levels may have appeared to be administration-dependent (i.e., pure caffeine; coffee (filtered, boiled, or espresso); energy drink) but it was not consistent. ...