The issue you are having, gentlemen, is primarily that you need more:
- Rest and sleep; not just sleep.
- Blood sugar to power your brain while it is processing this massive charge.
- Water.
- Vitamins and minerals.
- Omega 3/6/9 fatty acids
Basically you need more of everything that your brain uses to maintain itself.
It is not lowering your intelligence. It is simply that it is being pushed hard and it's not getting enough of what it needs. I suggest that a good solution is to get half or all of your exposure during the day, and allow your sleep to be unaffected. I will commonly switch it up and do my exposure during the day sometimes, and at night sometimes, and sometimes half and half. It helps a lot.
I also try to keep myself eating several small meals a day at more regular intervals instead of two or three at longer intervals. And I eat quality fish high in the Omega 3/6/9's regularly and frequently.
What we experiencing is a phenomenon where we processing the information we received. It is normal to feel sluggish, because you are processing new information while receiving another information (that need to be processed). And the amount of information is immense.
Not to mention a resistance (overwriting the current programming with a new) that produced while processing the information.