Perception of effort in morning-type cyclists is lower when exercising in the morning

Abstract

A recent study found that South African endurance athletes are likely to be morning-types and carry the PER3(5) allele, which has been associated with a preference for mornings. The aim of this study was to measure the response of morning-type cyclists to a standardised bout of exercise performed at different times of the day. Participants ncluded 20 trained male cyclists (age: 39.8 ± 7.7 years, VO2max: 51.0 ± 7.0 ml · kg(-1) · min(-1), training: 166 ± 98 km · wk(-1)), categorised as morning-types (mean Horne-Östberg score: 68.3 ± 5.5) and carrying the PER3(5) allele. They completed a 17-min sub-maximal cycling test at 60%, 80% and 90% of maximum heart rate (HRmax) at 06h00, 10h00, 14h00, 18h00 and 22h00. These morning-type cyclists reported higher ratings of perceived exertion when cycling at 60% (P = 0.044), 80% (P < 0.001) and 90% (P < 0.001) of HRmax during the evening (18h00 and 22h00) compared to the other sessions (0600, 10h00 and 14h00). This was despite absolute power output, speed and cadence displaying no time-of-day differences. Thus, morning-type cyclists perceive the same relative intensity workload to be harder in the evening compared to the morning. This may have implications for both training and competition scheduling, and highlights the importance of considering individual chronotype in sports in which diurnal variation may be relevant to training and competition.

Cronobiological effects over performance in individual sports: a systematic review (2000-2015)

“…Noutros cinco estudos verifica-se a interferência dos ritmos circadianos em algumas das variáveis estudadas, mas não em todas elas (Martin et al, 2001;Atkinson et al, 2005;Bessot et al, 2006;Hobson et al, 2009, Kunorozva et al, 2014.…”

“…Um estudo não verificou alterações ao longo do dia , um trabalho encontrou valores superiores de manhã (Martin et al, 2001) e um outro observou valores superiores de tarde, mas em atletas de cronotipo matutino (Kunorozva et al, 2014), o que poderá justificar este resultado.…”

“…Dois estudos debruçaram-se sobre a frequência de pedalada, com resultados divergentes: um não verificou alterações ao longo do dia (Kunorozva et al, 2014) mas um outro registou valores superiores de tarde (Moussay et al, 2003).…”

“…Quatro estudos não verificaram influências dos ritmos circadianos nos valores de potên-cia (Bardis et al, 2008;Cruz et al, 2014a;Kunorozva et al, 2014;Cruz et al, 2014b).…”

“…Apenas um estudo não encontrou diferenças significativas ao longo do dia (Blonc et al, 2010). No entanto, em testes superiores a 5 minutos essas diferenças não se verificaram para a maioria dos autores (Bardis et al, 2008;Cruz et al, 2014a;Cruz et al, 2014b;Kunorozva et al, 2014).…”