---
title: How the Body Budget Works- What Keys Alleviate Exhaustion
description: Your brain runs a body budget of glucose, oxygen and water. Why mental stress drains you like a marathon, and how to read your own statement.
author: Dr Marina Nani (Editor-in-Chief)
date: 2026-06-19T07:35:22.289Z
updated: 2026-07-26T21:19:53.508Z
canonical: https://richhealthmagazine.com/article/how-the-body-budget-works-and-why-a-desk-day-can-leave-you-as-drained-as-a-marathon
image: https://cdn.nanimediahouse.com/resume-genius-f2JMVDnarks-unsplash.jpg
categories: Sleep & Recovery
content_type: Guide
region: Global
publication: Rich Health Magazine
access: members
schema_type: Article
---

*The brain's real job is balancing your body's biological resources, and learning to read the statement explains the exhaustion that discipline cannot.*

Your brain is not, whatever you were told, mainly for thinking. Its first and most important job is to keep a budget. Every second it is allocating and spending your body's biological resources, the glucose, oxygen, water and salt that keep you alive and moving, and it takes the task so seriously that it spends about a fifth of all your energy running the accounts. The neuroscientist [Lisa Feldman Barrett ](https://richwoman.co/book/how-emotions-are-made)named this the body budget. Once you can read the statement, the exhaustion that discipline never seems to cure stops being a mystery and stops being your fault.

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