There are many smart people in the scientific community who consider near death experiences (or recalled experiences of death RED), to be caused by purely physiological reactions.

A recent, much shared, paper¹ hypothesised exactly this, proposing that NDE’s result from a combination of physiological and psychological threat responses:

NDEs can result from impaired cerebral blood flow causing systemic hypotension, hypoxia and hypercapnia resulting in acidosis, and from increased neuronal excitability causing dysregulation of key neurotransmitter systems.
[…]
NDEs might be partially shaped by top–down processes and facilitated by non-pathological cognitive traits such as dissociation propensity.

The evolutionary roots of NDEs are thought to be linked to survival and coping mechanisms, with serotonin probably mediating calming effects through 5-HT_1A receptors and contributing to hallucinogenic aspects through 5-HT_2A receptor hyperactivation.

—Martial, C et al (2025).

Now, a new paper just published, aims to provide an antithesis to these arguments.

A Neuroscientific Model of Near-Death Experiences Reconsidered (pdf).

We cite important NDE elements that remain unexplained
by that model, as well as empirical data that are incompatible with it. We respectfully
suggest that, taken together, these points generate sufficient doubts to merit reconsideration of the completeness of that overarching model and suggest that a more comprehensive treatment of the literature would strengthen our understanding of NDEs and
their etiology.

–Bruce Greyson and Marieta Pehlivanova

Warning… this is an academic, scientific paper with much medical terminology. Nevertheless, it makes very interesting reading even for a layperson.

As the authors of this paper conclude; it is important to remain open to other than materialist/physiological explanations for NDE’s.
Explanations that are currently unknown or misunderstood.

1. Martial, C., Fritz, P., Gosseries, O., Bonhomme, V.,
   Kondziella, D., Nelson, K., & Lejeune, N. (2025). A
   neuroscientific model of near-death experiences.
   Nature Reviews Neurology, 21(6), 297–311. https://
   doi.org/10.1038/s41582-025-01072-z ↩︎