---
title: How to bust your energy and alleviate afternoon crashes this autumn 
description: Sleep pressure peaks a second time at about 2pm in laboratory studies, a standard coffee needs to be at least 8.8 hours before bed to leave sleep untouched, ...
author: Dr Marina Nani (Editor-in-Chief)
date: 2026-09-07T21:52:46.880Z
updated: 2026-09-07T21:52:46.895Z
canonical: https://richwoman.co/article/afternoon-slump-body-clock-autumn-caffeine-nap
image: https://cdn.nanimediahouse.com/pexels-a-weary-office-worker-leans-over-a-desk-in-a-modern-indoor-s-8465072.jpg
categories: Nutrition, Sleep & Recovery
content_type: Feature
region: United Kingdom
publication: Rich Health Magazine
access: members
schema_type: Article
---

In a [study led by Timothy Monk](https://pubmed.ncbi.nlm.nih.gov/8877121/), twelve volunteers had their lunch taken away and replaced with a small liquid feed every hour, and five of them still had a dip in alertness in the early afternoon. The researchers tied it to a twelve-hour rhythm in body temperature. Twelve people is a small study, but later work has put a second daily peak in the pull towards sleep at about 2pm, whatever was eaten at one.

Autumn leaves the dip where it is and shortens the daylight around it. On 1 October London gets 11 hours 41 minutes of daylight and the sun sets at 18:40. On 25 October the clocks go back, the day is 10 hours 9 minutes long and sunset is at 16:48. By 30 November the sun rises at 07:40 and sets at 15:57. The slump that arrived at two in September now arrives with the dark less than three hours behind it.

Of the standard advice for the afternoon slump, a caffeine curfew, a short nap, [ten minutes on the stairs](https://richhealthmagazine.com/article/small-walks-big-wins-how-ten-minutes-or-less-can-improve-your-mood-blood-sugar-and-energy), a smaller lunch and [regular sleep times](https://richhealthmagazine.com/article/8-steps-to-think-with-clarity-and-feel-renewed-energy-this-autumn) have trials behind them. Bright cool lighting, extra water for people at desks, the split of carbohydrate and protein at lunch and the idea of a 22C office optimum have weaker evidence than the advice suggests. The 90-minute coffee delay has none.

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