Partial body cryotherapy exposure drives acute redistribution of circulating lymphocytes: preliminary findings

Abstract

Partial body cryotherapy (PBC) is proposed to alleviate symptoms of exercise-induced muscle damage (EIMD) by reducing associated inflammation. No studies have assessed acute PBC exposure on peripheral blood mononuclear cell mobilisation or compared these with cold water immersion (CWI), which may inform how PBC impacts inflammatory processes. This trial examined the impact of a single PBC exposure on circulating peripheral blood mononuclear cells compared to CWI or a control. 26 males were randomised into either PBC (3 min at - 110 to - 140 °C), CWI (3 min at 9 °C), or control (3 min at 24 °C), with blood samples, heart rate, and blood pressure taken before and after exposure. Cytometric analysis determined that CD8⁺ T-cell populations were significantly elevated after treatments, with PBC increasing CD8⁺ T cells to a greater degree than either CWI or CON. Natural killer cell counts were also elevated after PBC, with the increase attributed specifically to the CD56^loCD16⁺ cytotoxic subset. This provides the first evidence for the effect of PBC exposure on redistribution of immune cells. An increase in circulating leukocyte subsets such as CD8⁺ T cells and CD56^loCD16⁺ natural killer cells suggests that PBC may induce a transient mobilisation of lymphocytes. PBC may thus enable a more efficient trafficking of these cells from the circulation to the site of initial cellular insult from exercise, potentially accelerating the process of cellular recovery. This provides novel evidence on the use of PBC as a recovery treatment and may also have applicability in other clinical settings involving the recovery of damaged skeletal muscle.

Keywords: Acute stress response; Lymphocyte mobilisation; Partial body cryotherapy.

Fig. 1

Circulating cell numbers for individual study participants. CD4⁺ T cells (A), CD8⁺ T cell (B), NK cells (C), and the CD56^loCD16⁺ NK cell subset (D) at 15 min of rest, and at 30 min post-exposure. *Denotes significant time effect; ^#denotes a significant time-by-treatment effect (p ≤ 0.05). PBC partial body cryotherapy, CWI cold water immersion, CON control. Paired numbers from each participant are joined by a line

Fig. 2

Phenotype of CD16⁻ and CD16⁺ NK cells in individual participants. Each row in the heatmap indicates the percentage of cells positive for each marker listed on the left, while each column represents an individual participant, grouped as indicated by time of sample and treatment group. Rest 15 min of rest, post immediately post-exposure, PBC partial body cryotherapy, CWI cold water immersion, CON control group