Core Body Temperature Negatively Correlates with Whole-Brain Gray Matter Volume: A Pilot Study in the Context of Global Warming

Global warming has been associated with various adverse effects on human physiology, yet its potential impact on brain structure remains largely unexplored. The present pilot study investigated the relationship between core body temperature and whole-brain gray matter volume (GMV) in healthy adults. Twenty-seven participants (19 males, 8 females; mean age = 38.6 ± 10.3 years) underwent MRI scanning and core temperature assessment. Correlation and partial correlation analyses were performed to examine the association between core body temperature and GMV, controlling for demographic and physiological covariates summarized by the first principal component. Core body temperature showed a significant negative correlation with whole-brain GMV (r = -0.496, <i>p</i> = 0.009; 95% CI = -0.737 to -0.143) and a trend-level significant partial correlation after covariate adjustment (r = -0.373, <i>p</i> = 0.060; 95% CI = -0.660 to 0.008). These trends remained after correction for multiple comparisons using the Benjamini-Hochberg false discovery rate. Exploratory analyses across 116 AAL regions identified the left Fusiform gyrus as showing a significant negative correlation with core body temperature (r = -0.643, <i>p</i> < 0.001). Given the modest sample size, these findings should be interpreted cautiously as preliminary, hypothesis-generating evidence. They suggest that even subtle variations in body temperature within the normal physiological range may relate to differences in global brain structure. Possible mechanisms include heat-induced inflammation, oxidative stress, and increased metabolic load on neural tissue. Understanding how individual differences in body temperature relate to brain morphology may provide insights into the neural health consequences of rising environmental temperatures.