> [!tldr] Adaptation responds to intensity, not difficulty. In many contexts, "Intense" and "difficult" can often be used interchangeably. If something is *intense*, it is usually also *difficult*.[^1] A particularly [[HIIT|hard sprint]], [[Squat]]ting near a PR is going to be both *intense & difficult*. ![[Intensity and Difficulty are Different 2026-02-18 18.36.49.excalidraw.svg]] %%[[Intensity and Difficulty are Different 2026-02-18 18.36.49.excalidraw.md|🖋 Edit in Excalidraw]]%% Without proper recovery, you cannot really enter into the intensity zone necessary to drive sufficient adaption. Things *feel* intense, but really they are just *hard*. Working out too frequently or otherwise not properly attending to your recovery (drinking, [[Stress]], not [[Protect Sleep|sleeping enough]], etc) is sort of akin to [[Chronic Low-Level Inflammation]]. Your body is constantly in the "this is hard" range without entering into the range necessary to *drive* adaptation or the range necessary to *allow* adaptation. Another view of this, a more zoomed out "holistic" view over the course of days or weeks: ![[Intensity and Difficulty are Different 2026-02-18 19.17.45.excalidraw.svg]] %%[[Intensity and Difficulty are Different 2026-02-18 19.17.45.excalidraw.md|🖋 Edit in Excalidraw]]%% This is [[Avoid the Yellow Zone - Train in Green or Red]]. **** # More ## Source - [^1]: A roller coaster may be a case of "intense but not difficult"