Yes, this was actually explained as one of the secrets that some successful people have by Brian Tracy, it's called productivity cycle or something like that, and it lasts 4 or 6 weeks if I remember correctly.

Basically you can't expect to have the same level of energy and good mood every day, you'll be a bit different each day, but you can predict how you'll feel in advance. If you keep track of your general mood at the end of the day (or the impact this had on your activities like you're doing already), you'll soon be able to predict which days you'll be performing at your best.

Now what does this mean in practice? Two things. First, if you know in advance in which days you'll be at your top, you can plan activities that require your maximum concentration during those days. Second, if you know in advance which days are the worse, you can use mood-enforcing techniques like self affirmation to keep your energy levels high.

Does it really work? I don't have enough data to back this up, but you know from your direct experience that this cycle does indeed exist for you, and I know from mine as well. That's why I'm including a way to track your mood in one of the projects that I'm working on.

I'm curious to hear is someone else has similar experiences.

Hey
I get very similar patterns when working with deadlines. I might have to be on for three solid days to meet a big deadline and then once i'm done, i always feel great and try to bring the same intensity and energy to a non time sensitive project. However I can never maintain that peak for long and it always drops off a little. And i'm left cursing my screen. I used to call it deadline hangover. Now after 3-4 days of high intensity work i usually build some downtime into my schedule. While i want to be firing on all cylinders 24/7, I've learned that forcing myself to take time out and rest and renew is vital to my overall productivity.

Hey, great suggestion here Oscar. I already do a lot of tracking, so I can go back through my old notes and look... I'll do that, cheers for the idea. Sounds promising.

All good suggestions. Re: not pushing too hard, I used to think that was nonsense, but I've come around. Burnout is real. When you feel yourself coming up to your limit, much better to scale down instead of try to crash through. Well, that's if it's your *real* limit and not just fear/procrastination/whatever. Knowing the difference is kind of an art, but important and value. Good comment here, cheers.

I've noticed a similar pattern with myself. When sustained effort does not give sustained results, that sounds a lot like habituation (http://en.wikipedia.org/wiki/Habituation), where the brain does not respond as strongly to stimuli it has been exposed to for some time. If that is the case, then the solution might be to change project for a few days until the stimuli is novel again, as the OP suggested. Of course, fatigue may also play a role, so taking it easier for a day could help in combination. This also reminds me of One Week On, One Week Off that Steve Pavlina describes.

I've noticed the exact same thing, in fact, I've spent faaar to much time reading your blog today, but the past few days have been immensely productive.

I actually think it's a good thing. It gives us a chance to assimilate our new knowledge. It's like the work equivalent of REM sleep. I don't feel guilty for not being 100% "on" every day. Because even the bad days are productive in their own way. You stumble around and learn random things that you don't have an immediate use for, but expands your general awareness of the world.