Diurnal variation in cycling performance: Influence of warm-up

Abstract

We examined the effects of time of day on a cycling time trial with and without a prolonged warm-up, among cyclists who tended towards being high in "morningness". Eight male cyclists (mean +/- s: age = 24.9 +/- 3.5 years, peak power output = 319 +/- 34 W, chronotype = 39 +/- 6 units) completed a 16.1-km time trial without a substantial warm-up at both 07:30 and 17:30 h. The time trial was also completed at both times of day after a 25-min warm-up at 60% of peak power. Power output, heart rate, intra-aural temperature and category ratings of perceived exertion (CR-10) were measured throughout the time trial. Post-test blood lactate concentration was also recorded. Warm-up generally improved time trial performance at both times of day (95% CI for improvement = 0 to 30 s), but mean cycling time was still significantly slower at 07:30 h than at 17:30 h after the warm-up (95% CI for difference = 33 to 66 s). Intra-aural temperature increased as the time trial progressed (P < 0.0005) and was significantly higher throughout the time trials at 17:30 h (P = 0.001), irrespective of whether the cyclists performed a warm-up or not. Blood lactate concentration after the time trial was lowest at 07:30 h without a warm-up (P = 0.02). No effects of time of day or warm-up were found for CR-10 or heart rate responses during the time trial. These results suggest that 16.1-km cycling performance is worse in the morning than in the afternoon, even with athletes who tend towards 'morningness', and who perform a vigorous 25-min warm-up. Diurnal variation in cycling performance is, therefore, relatively robust to some external and behavioural factors.

Effects of Circadian Rhythm on Balance Performance

“…In studies that support the findings of our study, the physical performance of swimmers [41] and cyclists [30,42] was reported to gradually increase throughout the day, and a positive correlation with body temperature was found. In a study on the comparison of body temperature and jumping score at 10:00 and 17:00, body temperature (36.9 vs. 37.2°C; p < 0.001) and peak power output of jumping (5248 vs. 5413 W; p < 0.001) were found to increase at 17:00.…”

“…Some other factors like age, the type and intensity of exercise, jet-lag, and sleeplessness also affect these daily changes [15,29,30].…”

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.…”

Human circadian rhythms and exercise: Significance and application in real-life situations

“…Oxygen consumption and heart rate at the lactate threshold intensity 39) Time to exhaustion in the heat 42) 16.1-km cycling time trial 41) Short-term power output 27,28) No time of day variation Adverse cardiovascular events 45,46,55,56) Exercise-induced adverse cardiovascular events 57,58) Higher risk in the morning than in the afternoon and evening…”

“…Interestingly, studies examining other indices of endurance capacity have demonstrated a circadian rhythm or diurnal variation suggesting evening superiority: higher oxygen consumption and heart rate at the lactate threshold intensity 39) , higher aerobic contribution to energy production during 30 seconds of maximal pedaling 40) , and a faster record in a 16.1 km cycling time trial (about 23 minutes) 41) .…”