# Impact of peripheral skin cooling on neuroendocrine leukocytic and hematological reactions during Hypergravity

## TL;DR

This study explores how peripheral skin cooling affects the body's stress response during hypergravity, finding potential benefits for cardiovascular resilience.

## Contribution

The study introduces peripheral skin cooling as a method to enhance norepinephrine responsiveness during hypergravity exposure.

## Key findings

- Peripheral skin cooling increased serum osmolality during hypergravity exposure.
- Norepinephrine levels correlated with the cumulative +Gz stress index in the cooling group.
- Baseline serum metanephrine may serve as a marker for hypergravity resilience.

## Abstract

Optimal neuroendocrine responses are essential during hypergravity (+Gz) exposure. Peripheral skin cooling (PSC) may enhance neuroendocrine function, potentially improving +Gz resiliency and influencing leukocyte and hematologic factors. This study investigated whether PSC augments the cumulative +Gz stress index (CGSI) and shifts it toward noradrenergic dependency. Eighteen men underwent a graded +Gz profile in a crossover design, with PSC applied using Arctic Sun cooling pads. Neuroendocrine and blood profiles were assessed pre- and post-+Gz. CGSI did not differ between groups, but serum osmolality increased only in PSC (p = 0.03). In PSC, CGSI correlated with norepinephrine (p < 0.01, r = 0.71) and other markers, suggesting enhanced norepinephrine responsiveness despite similar serum levels. This response may be cardio-protective for space missions and ICU patients. Additionally, baseline serum metanephrine emerged as a potential marker for +Gz resilience, with PSC showing potential leukocytic and hematologic involvement in CGSI.