I’ve been doing a little detective work and here’s what I’ve found:
CrossFit (or at least my opinion of CrossFit’s opinion 🙂 ):
Keep the time of day that you train constantly varied. You should condition yourself to be able to perform on demand at any task assigned. Routine is the enemy… and you know what we do to our enemies (ok, I might have added in the last sentence).
Marks Daily Apple (full article):
Performance: “Raw power and performance in weight lifting, cycling, and sprinting is highest in the afternoon and evening. Stamina does not increase or decrease, however, and the changes in performance may be mitigated by more extensive warmups. If you’re a high level athlete or really interested in how you perform, afternoons and evenings are best. If you’re just trying to get and/or stay fit, strong, and healthy, morning workouts are just fine.”
Hormonal Effects: “Don’t hop directly under the bar in your pajamas with bleary eyes. Take the time to wake up and relax before working out. That might mean pushing your morning CrossFit class to an afternoon session, or at least a late morning one. We know that cortisol is normally elevated in the mornings, and exercise increases cortisol, so be aware of how the two interact.”
Health: “Evening/afternoon sessions seem to be somewhat more protective and beneficial, but morning sessions are also helpful – just less so. And there are other parameters on which diurnal variation has no effect, so it’s not a clear cut answer either way. Let’s put it this way – both are good.”
“As for me, I like late morning workouts, but that’s just because late morning works best for me and my schedule. I’m not trying to optimize my hormonal responses, boost my metabolism, or maximize my workout grip strength. I’m just working regular exercise into my daily routine, when and where it fits.
You can read the research and follow the links, but ultimately, the best time of day to exercise is the time of day that works for you. If you’re dead tired after work, perhaps a morning session is the answer. If late night workouts keep you buzzed and awake, move them back an hour and go from there. Also, as the context of your life changes, you’ll have to mix up your workout schedule on the fly. Get a bad night’s sleep? Your cortisol is raging, and a late afternoon workout is probably better than an early morning one.”
BodyBuilding.com (full article):
The following compilation reviews points of interest for the average circadian rhythm:
-Testosterone is at it’s daily peak.
-Mental alertness peaks late morning.
-Memory works best.
-Body temperature is still low.
-Pain tolerance is highest.
-Possible point of low energy around noon.
-Late afternoon, adrenalin and body temperature has a rising trend.
-Late afternoon, there is an optimum period of mental/physical function balance.
-Coordination, stamina, body temperature at a peak.
-Lung performance is best.
-Flexibility and strength at their greatest.
-Mental focus is waning.
-Starting around 9pm, the body produces additional melatonin, preparing for sleep.
-Bodily processes should be slowing down in preparation for sleep.
Notice that many systems will not be at peak performance at the same times of day. Because of this, and with the addition of individual differences, it is difficult to give a time at which a person will be at their best. But with the given information so far, I would suggest late afternoon as a time of optimum performance in most of your body’s processes.
The Russians (or at least the Russians of the late 70’s and early 80’s):
YV Shcherbin and PM Mironenko did a study of weightlifters (Olympic Lifters) in 1980 and found that:
“the electrical activity of the neuromuscular apparatus over a 24-hour period increases in activity were noted from 12PM-2PM and 6PM-8PM”
“there are two periods during the day when there are rises in strength — from 11AM-2PM and from 6PM-9PM. Muscular power increases by 10-30% at these times.”
I’ll spare you the accompanying typewriter chart/graph. I’ve added a link to “typewriter” for Kale and Kailen:)
Overall what’s posted above is also what I’ve experienced. It seems like training sometime in the afternoon/evening is the best bet. Personally I’ve found when I’m strictly training 3PM-5PM yields the best results, my heads in the game, my body is generally warmed up, and I feel primed to get after it. These days though I train between 10:30AM and 12PM as it affords me the longest recovery before night classes and makes the most logistical sense. I’ve trained late in the day and found anything up to 9PM is good and anything after 9PM negatively affects my sleep. I’ve never trained in the morning prior to 9AM as I find it hard enough to count my balls and get the same number twice. That said it’s important to keep in mind we’ve been talking about optimal times of day to train based on performance and training as a priority. You still have to take into account life (daily commutes, jobs, kids/family, etc) which may offset the best time for you to train.