Agree with you 100%.
Your emotional map (software) is linked to your guts (hardware).
This is so true and when accumulated toxins start to send the wrong signals to to the mind, a chemical imbalance is created.
Toxins are acidic thus your legs will feel heavy exacerbated by being sedantary.
The only way to get round this is radically different diet (not easy when you are served dioxin-laden meals on the flight deck) and take mega-doses of probiotics.
You need to sweat sweat sweat it out so sports or steam.
Surprisingly your question is on the cover of a serious French weekly just out!
La bibliothèque - Le Point
"Your Gut, Your Second Brain"