Viewpoint: The gut microbiome and thermoregulatory response: Relevance of the microbiota in heat-related illness?

Abstract

The impact of heat stress on the human body during physical activity is well established with physiological strain elevated across many organ systems as the body responds to heat storage with the initiation of integrative heat loss pathways (Foster et al., 2026). In circumstances where the combination of the intensity of the activity and the temperature and the humidity of the environment at the skin surface do not allow for sufficient rates of heat dissipation, heat storage leads to increased core body temperature (Foster et al., 2026). In some exercising individuals, excessive heat storage is a factor contributing to exertional heat illness (EHI), a potentially life-threatening condition. The mechanisms associated with heat-related illnesses are multifactorial and may demonstrate inter-individual differences (Gibson et al., 2026); however, the gastrointestinal tract is often implicated (Foster et al., 2026). Hyperthermia, alone or in conjunction with physical activity, can cause gastrointestinal injury, and bacterial translocation into the circulation initiating a systemic inflammatory response and multi-organ failure. The gastrointestinal tract demonstrates marked differences in functionality between individuals with the gastrointestinal/faecal microbial composition – often referred to as the microbiome – recently suggested as a factor modulating the magnitude of disturbance and inflammatory response during thermoregulatory strain.