My n=1 anecdotal experience is that being used to morning workouts doesn’t help that much. At least when I was running a lot, my afternoon runs were probably 30-40 seconds per mile faster for the same RPE. Despite most of the workouts being at 6 in the morning.
While it’s true that people generally perform best in the PM, in practice I perform much better in the early AM. When I wait till the PM, I feel tired by the time I start. Training after 4 pm is a disaster and messes with sleep. Of course, if I would wake up at 7 am instead of 4:30 the preferred times would change but I’m guessing it would still be shortly after waking up. Eating solid food before an intense work-out often creates a problem - if I simply start drinking carbs the moment I start peddling I perform best.
Back in my college days I always ran my best races under the lights at night. In my studies I remember finding research articles that found VO2 levels were actually higher in the evening than morning. That was a while ago though. The hard part is waiting around all day for the race…
Now days morning works best… not from a performance standpoint but due to convenience.
I guess I’m the outlier, as I much prefer getting in TR before work. I’m a chef, so I’m on my feet all day, and I commute to work via bike, so my legs are generally more tired in the evenings, and I struggle to complete workouts. I pretty much nail them in the AM tho
Studies show that your glycogen levels are at their lowest upon waking up. Thus, no matter how we fuel at dinner the night before, it’s still at its lowest. With lower glycogen in the morning our bodies pull fuel from fat stores. And I think we all know now how much we use sugar/glycogen/carbs for energy on our hard efforts. Fat for those slow burn workouts ie Z2. So it would make sense most, not all, people struggle to put in efforts early morning.
Prime time of day to train, is that 1-2:00pm range.
I’m no scientist, but I have slept at a holiday inn express once!!
Haven’t read everything, but your body temp is another factor, and I believe peaks in early afternoon. I can remember listening to a podcast about this related to strength training (Huberman and Andy Galpin?) where that late morning - early afternoon was the optimal time based on body temp, glycogen, etc. and that there was a performance difference.
N=1 - I’m stronger and have more in the tank if I wake up, have coffee and breakfast, and wait a couple hours after that at least. But, beyond early afternoon and then I start to go the other way. Sweet spot is after breakfast and coffee, but have lunch and bigger meals later. But, if the time I have is 5:30 AM, then game on, get up, down a caffeinated gel, and get after it.
And yes, performing better can mean better adaptation if you’re able to do more work (e.g. lifted heavier or more reps, or finished an all out interval stronger / longer) but if it was just the RPE of a bike workout, I don’t think there’s a difference there.
What you do during the day definitively matters. I feel like I only have so much energy to spend during a day, and whatever comes first (training or work) gets the larger chunk. Train first, but be very tired in the afternoon, or work first, but don’t have any motivation left to train after.
Contridicts the one on the TR podcast then which I am sure said 2:30 - 3pm
A quick google and I can find several studies that say peak performances was found to be in the late afternoon to early evening. One was on strength though a peakbmuscle contractions.
There is also a study that says continously training in the morning can raise morning performance to afternoon levels, however if the same training was done in the afternoon performance improves more and the gap to morning performance widens.
Google and there is plenty of info… too lazy to link them all, I go up at 4:45am lol
Without reading any of the studies… “early afternoon” is likely the largest overlap between “larks” and “owls”. Everybody can somewhat perform in the middle of the day. We are also culturally habituated to be awake and in performance mood at that time. (It might be interesting to repeat that study somewhere where people normally have a long day-time fiesta?)
My old trainer used to have us do FTP tests at the start of Mt Baldy (a nice ramp for a nicer FTP number), yet most of my training was done on one of the local dry river bed trails or rolling canyon roads.