The fitness industry has a remarkable ability to take something simple and futz with it until you need a spreadsheet. Apparently, just going to the gym wasn’t complicated enough. Now we have optimal meal timing, optimal sleep timing, optimal supplement timing, optimal carbohydrate timing and, of course, optimal training timing. Your biological clock must be consulted before squats. God forbid you train legs at 10:30 a.m. when your circadian rhythm had you scheduled for 4 p.m.
Well, some researchers actually put this one to the test, and they did it considerably better than the usual exercise study involving eleven college kids and a leg-extension machine. A randomized controlled trial published Sept. 25 in the Journal of Cachexia, Sarcopenia and Muscle took 108 men and women between 60 and 80 years old and first figured out when each person was actually strongest. They tested them at 8 a.m., noon, 4 p.m. and 8 p.m. on separate days. Then they assigned them to train either around their personal strongest time, their weakest time, or not train at all.
That’s a pretty clever setup because people really did have stronger and weaker times. On average, strength varied about 11 percent during the day, although individuals ranged from almost no difference to a whopping 34 percent. Peak strength showed up most often in the afternoon and evening. So the premise wasn’t stupid. You’re probably stronger at certain times of day, and the researchers proved it.
Then came the part Instagram optimization gurus aren’t going to like.
Does Training at Your Biological Peak Time Produce Bigger Muscle Gains?
After 12 weeks, training when the subjects were naturally strongest produced no clear advantage in strength or lean-mass gains over training when they were naturally weakest. The researchers also compared people training at the various fixed times and couldn’t find a consistent superior time there either. Basically, your body may perform somewhat better at 4 p.m. than 8 a.m., but that didn’t translate into noticeably more muscle or strength over the course of the study.
Now, don’t run wild with this. These were healthy older adults, average age 67, not 25-year-old competitive bodybuilders on 8,000 calories a day and enough gear to make a racehorse nervous. Ninety-three participants made it into the final analysis. They resistance-trained twice a week with five exercises, three sets each, plus one moderate cycling session. So we can’t automatically declare that time of day never matters for anybody under any training circumstance. Science doesn’t give you that license.
But this study does reinforce something people who have trained for a long time already know. The best time to train is very often the time you can actually keep training.
The adherence numbers were over 90 percent in both training groups. That’s the part I find more interesting than whether someone’s quads possess a circadian sweet spot. A perfect program you miss twice a week isn’t a perfect program. A theoretically inferior workout you do religiously for ten years is going to kick its ass.
Peak Performance vs. Muscle Adaptation: What the Research Shows
There’s also an important distinction between performance and adaptation. You may very well feel stronger later in the day. The subjects frequently were stronger later in the day. If you’re attempting a one-rep max, competing in powerlifting or trying to produce your absolute best performance at a particular hour, that could matter. What this study says is that being temporarily stronger when you train didn’t result in better long-term muscular adaptation in this particular population. That’s not the same question.
Which brings us back to the guy setting his alarm for 4:17 because somebody on a podcast told him testosterone, cortisol and Jupiter’s gravitational field make that the anabolic window.
Relax.
Train when your life allows you to train hard and consistently. Eat correctly. Recover. Add weight or reps when you can. Keep doing it.
We’ve spent 50 years trying to discover the secret time to lift weights.
Turns out the important part may still be lifting the weights.