RehabMove 2018: HOT BATHS: AN EFFECTIVE SUPPLEMENT TO EXERCISE IN DISABILITY?

Abstract Body temperature elevations are crucial to induce increases in markers associated with the health benefits of exercise. In support, anecdotal, historical and epidemiological evidence advocates the health benefits of alternative interventions resulting in passive body temperature elevations, such as Sauna or hot water immersion (HWI) therapy. This may be particularly relevant for populations with restricted ability to be physically active. PURPOSE: Here we present findings of four studies investigating HWI in both able-bodied individuals (AB) and individuals with cervical spinal cord injury (CSCI), with a focus on its impact on inflammation and glycaemic control. METHODS: All studies employed HWI protocols that increase body temperature by 1–2°C by passively immersing participants in hot water for 1 hour. RESULTS: An acute bout of HWI increases the postprandial peak glucose concentration after immersion when compared with a control condition which does not elevate core temperature. Chronically, a two-week intervention of repeated daily HWI decreases resting blood glucose and insulin concentrations. Further, the acute inflammatory response to HWI, evidenced by elevations in interleukin-6 and interleukin-1ra, does not differ between AB and CSCI. This contrasts with the blunted inflammatory response to exercise in CSCI. CONCLUSIONS/OUTLOOK: Our experimental data show that HWI leads to beneficial glycaemic and inflammatory responses that can match, and for some markers even exceed, the responses found following exercise. Although the effect of chronic HWI therapy has yet to be confirmed in populations with disability, HWI may hence represent an attractive alternative and/or supplement to exercise for populations whose ability to be active is restricted