Table 1. Detailed timeline for experimental steps B and C at the MRI suite.

Steps	Sub steps	Additional time between sub steps	Time
B	MRI safety assessment (including explanation of CWI procedure and signing consent form)		5 min
	Pre-CWI mood assessment		2–3 min
		Changing into MRI-compatible clothes (if required)	1–3 min
C	Position participant in the scanner (pre-CWI)		3 min
	Pre-CWI scanning		4.5 min + 13.12 min = 17.62 min
		Localise scan to position the brain	1 min
		Get participant from the scanner, change into swimwear	3–4 min
		Instrument with ECG electrodes, nose clip, and mouthpiece	2–3 min
		Taking baseline measurements	2–3 min
	Cold-water immersion		5 min
		Remove ECG, nose clip, and mouthpiece	1 min
		Drying and changing into MRI-compatible clothes	M = 5.83, SD = 2.09*
	Position participant in the scanner (post-CWI)		2–3 min
	Post-CWI scanning		13.12 min
		Localise scan to position the brain	1 min
	Total time:		~62 min**