Impact of Cold Chest Pack on Cardiac Output, Stroke Volume, and Total Peripheral Resistance: A Counterbalanced, Randomized-Crossover Trial in Healthy Individuals.

Background: Cold chest pack (CCP) is a hydrotherapeutic technique used to improve cardiorespiratory outcomes, however, their effects on the cardiovascular system remain substantiated by credible scientific research. Hence, the present study aimed to evaluate how CCP affects central hemodynamics in healthy volunteers.

Method: This study was a randomized, open-label crossover trial with 24 healthy male participants between 18 and 26 years of age. The study employed a counterbalanced design in which participants were randomized to either a dry chest pack (DCP) or a CCP for 20 minutes, followed by a 2-day washout period during which they were switched to the opposite phase. Central hemodynamics and heart rate variability were measured at baseline, throughout the session, and ten minutes following the intervention.

Results: Our findings showed a significant decrease in cardiac output (P = .03) with an increase in total peripheral resistance (P = .004), mean arterial pressure (P < .001), systolic blood pressure (P < .001), and diastolic blood pressure (P < .001) during the use of a CCP. These changes were retained after 10 minutes, except cardiac output (P = .32), and a persistent decrease in heart rate (P < .001) during and after the CCP use. These changes were not observed in DCP and the stroke volume was not impacted in either group (P > .05). A significant increase in mean RR intervals (P < .001) and the percentage of differences between adjacent normal heartbeats (NN intervals) that are greater than 50 milliseconds (P < .01) was observed only after the application of a CCP.

Conclusion: The results of this study showed the application of a CCP for 20 minutes affects central hemodynamics and heart rate variability; these results may be considered when using CCP therapeutically.