Between-visit reproducibility of cerebrovascular and cardiovascular reactivity during the cold pressor test

The cold pressor test (CPT) is a painful test used to assess cardiovascular and cerebrovascular reactivity. Past studies examined between-visit reproducibility of cardiovascular reactivity during the CPT but not cerebrovascular reactivity. Therefore, we performed a retrospective analysis to test the hypothesis that cerebrovascular responses during the CPT would not differ and would have moderate relative agreement between visits. Fifty young adults free from overt disease, not taking pain-modifying medications, completed two trials ≥48 h apart. We measured middle cerebral artery blood velocity (MCAv) via transcranial Doppler ultrasound, beat-to-beat blood pressure (BP) via photoplethysmography, and end-tidal CO₂ ([Formula: see text]) via capnography during a 5-min baseline and 2-min CPT. We calculated reactivity as the change (Δ) from baseline to the first and second minute of the CPT. There were no between-visit differences in baseline mean BP, mean MCAv, or [Formula: see text] (Ps ≥ 0.24). There were no between-visit differences for Δmean MCAv (Ps > 0.75) or Δmean BP (Ps > 0.07). Relative agreement between visits was moderate for Δmean MCAv [intraclass correlation coefficient (ICC): Δmin-1 = 0.68, Δmin-2 = 0.72] and moderate/good for Δmean BP (ICC: Δmin-1 = 0.65, Δmin-2 = 0.80). Our data suggest that Δmean MCAv to the CPT does not differ between visits, while the relative agreement is similar to BP reactivity. Furthermore, relative agreement was higher during minute 2 than minute 1 for key variables. These data extend our knowledge of the reproducibility of CPT reactivity. These findings will inform future research aimed at comparing cardiovascular and cerebrovascular reactivity as health markers between groups.NEW & NOTEWORTHY We present novel data on between-visit cerebrovascular and cardiovascular reactivity reproducibility during the CPT. Relative agreement was stronger for BP and mean MCAv reactivity during the second minute of the CPT, suggesting that future work should use protocols >1 min. Cerebrovascular and cardiovascular variables had similar reproducibility; changes in [Formula: see text] and perceived pain significantly predicted CVCi reactivity. Controlling [Formula: see text] could improve reproducibility; future work could consider pain perception while assessing cerebrovascular reactivity to the CPT.