A scientific study has found that body temperature has a greater impact on lifespan than metabolic rate. The results, published by researchers from the Shenzhen Institute of Advanced Technology (SIAT) affiliated with the Chinese Academy of Sciences, in collaboration with Wenzhou University and the University of Aberdeen, appeared in the journal Nature Metabolism.
According to Neuroscience News, the study's findings provide a biological interpretation of the saying "live fast, die young," which is often used to comment on how people with risky and fast-paced lifestyles tend to experience accidents and die prematurely. However, in biology, the explanation has a somewhat different origin, as it has been observed that animals with high metabolic rates, or those that "live fast," tend to die earlier than those with slower metabolisms.
**Longevity**
The relationship between metabolism and lifespan is less clear in some organisms. Generally, interventions that lead to increased lifespan, such as caloric restriction resulting in lower metabolic rates, align with the idea of "live fast, die young." Although exercise increases metabolism, it seems, on average, to help individuals live slightly longer.
One issue with determining the effect of metabolism on lifespan is that metabolism is often associated with changes in body temperature. Typically, lower metabolic rates are associated with lower body temperatures. Thus, when calorie-restricted mice live longer, it is not clear whether the longer lifespan is linked to lower metabolism or lower body temperature.
**Opposing Trends**
Researchers used an unusual situation where metabolic rate and body temperature move in opposite directions to identify the more significant factor. Professor John R., a co-researcher in the study, noted that when experimental mice are exposed to high temperatures, at the upper end of the thermoneutral zone, their metabolism decreases while their body temperature rises. The findings indicated that exposing rodents to these conditions shortens their lifespan.
**The Most Important Mediator**
Professor Zhao Qigong, a co-researcher from Wenzhou University, stated that the results suggest that body temperature appears to be the most important mediator of lifespan compared to metabolic rate. For this reason, the saying might need to be changed from "live fast, die young" to "live cool, die old."
