As a night owl, I view morning people with a mix of admiration and jealousy, or if I am prematurely awoken by one, outright hostility. On the flip side, many people just can't fathom the idea of working out in the evening because their bodies and minds are already halfway to the land of nod.
It has been known for ages that some people just perform better at certain times of day, and believe it or not, there is genetic basis for our patterns of sleep and waking, otherwise known as your "circadian rhythm". Scientists have found a gene variant called PER35 that is expressed in morning people but not in those who feel more alert at night.
A group of researchers looked into this further and subjected a group of early risers from South Africa who carry the PER35 gene variation, who also happened to be endurance athletes, to a battery of cycling tests.
The athletes were made to cycle at various output levels at different times of day and night while the researchers measured parameters such as speed, power, cadence, and the athletes' perception of the amount of work they had done.
While the measured biological parameters remained identical through tests at various times of the day, the athletes reported feeling as though they were working a lot harder in the evening, despite clocking up exactly the same amount of work they were doing in the morning.
These results reinforce what many of us already know – the time of day that we train can influence motivation and feelings of fatigue. A workout that feels less like work is going to be easier and more enjoyable than the one you're struggling through when you feel like you should be asleep, and will leave you more inclined to push further for bigger gains.
Although training at less than optimal times during the day or night is sometimes necessary because of the other things that go on in life, aiming to work out during your peak alertness period is a great idea to maximise benefits and make hard work feel less like hard work, and there's now science to prove it.
Kunorozva L, Roden LC, Rae DE. Perception of effort in morning-type cyclists is lower when exercising in the morning. J Sports Sci. 2014 Jan 30.