Whole-Body Cold Stimulation Improves Cardiac Autonomic Control Independently of the Employed Temperature

Area of Science:

• Physiology
• Cardiovascular Health
• Autonomic Nervous System Research

Background:

• The autonomic nervous system (ANS) is implicated in mediating whole-body cold stimulation (WBC) benefits.
• Assessing WBC effects on the ANS is challenging due to varied protocols and complex data interpretation.
• Cardiac autonomic control (CAR) assessment requires standardized, interpretable metrics.

Purpose of the Study:

• To investigate WBC's impact on cardiac autonomic control (CAR).
• To evaluate CAR using the Autonomic Nervous System Index (ANSI), a composite proxy for autonomic balance.
• To compare WBC effects at two different temperatures (-55°C and -110°C) under a consistent protocol.

Main Methods:

• Heart rate variability (HRV) analyzed in 23 individuals with obesity undergoing 10 WBC sessions.
• WBC exposure involved 2-minute sessions at either -55°C (15 subjects) or -110°C (8 subjects).
• Measurements taken pre- and post-WBC at the first (T1) and tenth (T10) sessions, utilizing the ANSI for analysis.

Main Results:

• Both WBC temperatures significantly improved CAR, as indicated by increased ANSI scores post-treatment at T1 and T10.
• A significant enhancement in total RR interval variability was observed from pre- to post-treatment at T1.
• Overall improvement in cardiac autonomic control was noted from T1 to T10.

Conclusions:

• WBC effectively induces immediate changes in autonomic nervous system (ANS) control.
• WBC demonstrates a capacity for long-term modulation of cardiac autonomic control.
• The ANSI provides a valuable, simplified metric for assessing WBC's impact on autonomic balance.