The metabolic upper critical temperature of the human thermoneutral zone.
Level 5 - mechanism / opinion, no new human data
Narrative review evaluating conflicting physiological literature without systematic meta-analysis
PubMed 36462873 · doi:10.1016/j.jtherbio.2022.103380
What was done
The authors synthesized existing literature to evaluate the evidence for an upper critical temperature in the human thermoneutral zone, analyzing conflicting findings across studies and assessing how different heat exposure protocols influenced outcomes.
What was found
The abstract reports no numerical values. Existing studies diverged on whether a metabolic upper critical temperature exists in humans, with findings varying based on the type of heat exposure protocol used. Studies reporting an upper limit identified widely discordant temperature thresholds.
Why it matters
While the lower boundary of the human thermoneutral zone is well established, whether humans have an upper ambient temperature limit where resting metabolic rate begins to rise remains unresolved.
Limits
The abstract describes a narrative review rather than a systematic review or meta-analysis and provides no quantitative data, temperature values, or study counts. The underlying evidence base is characterized by contradictory findings and heterogeneous exposure protocols.
Cited by
- supports Both cold and heat exposure raise metabolic rate in the body.