[manmal]

Yes! My pool was quite drained 1 or 2 years ago, but I managed to enlarge it by taking longer breaks, shutting down completely on weekends, eliminating foods I'm intolerant to (gluten & lactose inflame my gut pretty quickly), introducing intermittent fasting (no food until noon), adding fish oil and vit D, switching from cardio to HIIT workouts, and keeping caffeine intake constant. I can now be highly productive for at least 7-8h per day, and then still focus on my family (vs turning into a couch zombie). Lack of sleep (< 6h; optimum is 8h) still kills me though.

I think intermittent fasting and fish oil did the most for me in this regard. Since quality of sleep is really important to my focus, it might be worth mentioning that zinc supplements do a lot for me here (but at least this remedy is purely anecdotal).