1. Baković et al. 2003

Spleen volume and blood flow response to repeated breath-hold apneas
Link: https://pubmed.ncbi.nlm.nih.gov/12819225/

Note:
Shows rapid spleen contraction in response to repeated breath-hold apneas, supporting the link between apnea, spleen response and temporary changes in oxygen-carrying capacity.

2. Baković et al. 2003 – full journal version

Spleen volume and blood flow response to repeated breath-hold apneas
Link: https://journals.physiology.org/doi/10.1152/japplphysiol.00221.2003

Note:
Journal of Applied Physiology version of the same study. Useful as the primary publisher link if you want a more formal source.

3. Schagatay et al. 2001

Role of spleen emptying in prolonging apneas in humans
Link: https://pubmed.ncbi.nlm.nih.gov/11247970/

Note:
Shows that spleen emptying contributes to repeated apnea performance and erythrocyte release, supporting the spleen-response mechanism behind breath-hold physiology.

4. Schagatay et al. 2001 – full journal version

Selected Contribution: Role of spleen emptying in prolonging apneas in humans
Link: https://journals.physiology.org/doi/10.1152/jappl.2001.90.4.1623

Note:
Journal of Applied Physiology version of the study on spleen emptying, erythrocyte release and repeated apneas.


5. Persson et al. 2023

Splenic contraction and cardiovascular responses are augmented after apnea compared with rebreathing in humans
Link: https://pmc.ncbi.nlm.nih.gov/articles/PMC10028099/

Note:
A more recent open-access study showing spleen-volume reduction after apnea, adding modern support to the spleen-contraction mechanism.