Article Impact Level: HIGH Data Quality: STRONG Summary of Journal of Thermal Biology, 126, 104017. https://doi.org/10.1016/j.jtherbio.2024.104017 Thomas J. James et al.
Points
- The study explored the effects of repeated hot water immersion (HWI) on vascular and hemodynamic function in individuals with type 2 diabetes mellitus (T2DM), focusing on endothelial dysfunction and cardiovascular risk.
- HWI significantly reduced stroke volume index, cardiac index, resting heart rate, and systolic blood pressure, while diastolic blood pressure remained unchanged.
- There were no significant improvements in macrovascular endothelial function (brachial flow-mediated dilation), microvascular responses (acetylcholine and insulin-induced), or plasma nitrate and nitrite levels.
- Participants underwent 8-10 sessions of 1-hour HWI at 40°C over 14 days, with rectal temperatures maintained at 38.5–39.0°C during immersion.
- HWI showed promise in improving hemodynamic parameters in individuals with T2DM but did not enhance vascular endothelial function.
Summary
This study investigated the effects of repeated hot water immersion (HWI) on vascular and hemodynamic function in individuals with type 2 diabetes mellitus (T2DM). T2DM is often associated with endothelial dysfunction, which increases the risk of cardiovascular disease (CVD). While previous studies have suggested that HWI can improve vascular function in healthy individuals, limited data are available on its effects in those with T2DM. In this study, 14 participants underwent 8-10 sessions of 1-hour HWI at 40°C over 14 days, with body position adjusted to maintain a rectal temperature of 38.5–39.0°C during immersion. The study assessed a range of vascular and hemodynamic parameters pre- and post-intervention.
The results showed that while HWI did not significantly improve measures of vascular endothelial function, it did have some positive effects on hemodynamic parameters. Specifically, stroke volume index (SVi), cardiac index (CI), and resting heart rate (HR) were significantly reduced after the intervention (SVi, p < 0.02; CI, p < 0.01; resting HR, p < 0.01). Systolic blood pressure (SBP) was also significantly reduced (p = 0.03), while diastolic blood pressure (DBP) remained unchanged (p = 0.56). However, there were no significant changes in brachial flow-mediated dilation (FMD), a measure of macrovascular endothelial function (p = 0.43), or forearm microvascular function, including acetylcholine (ACh) and insulin-induced responses (p values ranging from 0.51 to 0.86). Additionally, nitrate and nitrite (NOX) plasma levels did not change after the intervention (p = 0.38).
In conclusion, while repeated HWI in individuals with T2DM improved cardiac output, stroke volume, and systolic blood pressure, it did not significantly improve endothelial function, either in macrovascular or microvascular tissues. These findings suggest that HWI may be a promising intervention for improving certain hemodynamic parameters in individuals with T2DM but does not appear to enhance vascular function.
Link to the article: https://www.sciencedirect.com/science/article/pii/S0306456524002353
References James, T. J., Corbett, J., Cummings, M., Allard, S., Bailey, S. J., Eglin, C., Belcher, H., Piccolo, D. D., Tipton, M., Perissiou, M., Saynor, Z. L., & Shepherd, A. I. (2024). The effect of repeated hot water immersion on vascular function, blood pressure and central haemodynamics in individuals with type 2 diabetes mellitus. Journal of Thermal Biology, 126, 104017. https://doi.org/10.1016/j.jtherbio.2024.104017
