diff --git a/charts.tex b/charts.tex
index a36b6036628d6b75a0506605f7bd8d7ac22c50e9..e501b6ff167a7f706c1e46c3f4c69b1b48ddf2e7 100644
--- a/charts.tex
+++ b/charts.tex
@@ -247,7 +247,7 @@
 
     Fighting & Each round inflicts 1 \gls{fatigue}. \\
 
-    Holding Breath & 1 \gls{fatigue} per round. \\
+    Holding Breath & 1 \gls{fatigue} per negative \glspl{ap}. \\
 
     Marching & 1 \gls{fatigue} per mile. \index{Marching}\\
 
diff --git a/combat.tex b/combat.tex
index d35b0709d874d0e97fbe10f0801363808a60bd14..733c07c62f3e66a98beb3eb39ee568a3de5307fd 100644
--- a/combat.tex
+++ b/combat.tex
@@ -706,6 +706,11 @@ However, they can get up as by spending 1 \gls{ap}.
 
 Gaining the higher ground grants +1 to the Attack Bonus, as you target the enemy's head easier and gravity aids your downward swings.
 
+\subsubsection[Holding Breath: 1 \glsentrytext{fatigue} per negative \glsentrytext{ap} at the end of the round]{Holding Breath}
+
+Anyone holding their breath takes a number of \glspl{fatigue} equal to their negative \glspl{ap} at the end of the round.
+So someone ending a round on -3 \glspl{ap} would take 3 \glspl{fatigue}.
+
 \subsection{Manoeuvres}
 
 These additional actions cover different ways to engage with enemies.