The effects of cold exposure (cold water immersion, whole- and partial- body cryostimulation) on cardiovascular and cardiac autonomic control responses in healthy individuals: A systematic review, meta-analysis and meta-regression.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of intervention studies
PubMed 38663342 · doi:10.1016/j.jtherbio.2024.103857
What was done
A systematic review and meta-analysis of literature from PubMed, Embase, and Web of Science evaluating the effects of cold exposure (cold-water immersion, whole-body cryostimulation, and partial-body cryostimulation) on cardiovascular and cardiac autonomic control in healthy individuals. Measured outcomes included blood pressure, heart rate, and heart rate variability metrics: RR interval, root mean square of successive RR interval differences (RMSSD), low-frequency band (LF), high-frequency band (HF), and LF/HF ratio.
What was found
From 27 included studies, 24 were pooled in meta-analyses. Cold exposure significantly increased RMSSD (SMD = 0.61, p < 0.001), RR interval (SMD = 0.77, p < 0.001), and HF power (SMD = 0.46, p < 0.001), while significantly decreasing LF power (SMD = -0.41, p < 0.001) and LF/HF ratio (SMD = -0.25, p < 0.01), with changes persisting up to 15 minutes post-exposure. Cold exposure also resulted in a small reduction in heart rate (SMD = -0.16, p < 0.05) and a modest increase in mean blood pressure (SMD = 0.28, p < 0.001).
Why it matters
The findings quantitatively confirm that acute cold immersion and cryostimulation shift cardiac autonomic balance toward enhanced parasympathetic activity while producing a mild acute pressor response.
Limits
The abstract does not report the total participant sample size. Findings are restricted to healthy participants, limiting applicability to clinical or cardiovascularly vulnerable populations. Autonomic assessment was short-term (persisting up to 15 minutes), and heterogeneity stemming from differing cooling modalities and participant characteristics was noted.
Cited by
- partial Cold water immersion causes sympathetic activation for 15 to 30 minutes post-exposure, followed by an elevation in parasympathetic drive and heart rate variability of 20% to 50% for up to three hours.