ABSTRACT
The main objective of this review is to examine the impact of balneotherapy on serum and salivary cortisol concentrations. A systematic search was conducted in PubMed, Scopus, Web of Science, PEDro, and Google Scholar. The databases were screened from inception up until April 2024. After screening the scientific literature, 845 articles were retrieved and 17 studies, involving a total of 765 participants, were eventually included in the review. Among them, four were randomized controlled trials, five were non-randomized studies, and eight were pre-post studies with no control group. The evidence gathered in this review indicates a significant short-term reduction in cortisol levels in healthy individuals undergoing balneotherapy, particularly those experiencing high levels of stress. Conversely, in patients with rheumatic conditions (especially if elderly), increases in cortisol levels induced by balneotherapy can act as beneficial hormetic stress, reducing inflammatory mediators and improving pain and functional quality of life. The meta-analysis shows an overall trend of reduction in stress hormone levels, more pronounced in the intervention group undergoing mud-balneotherapy compared to the control group, a finding that, however, does not reach statistical significance (g=-0.11 [95% CI: -0.30; 0.08]; p > 0.05). Current scientific evidence demonstrates that balneotherapy has a positive impact on the regulation of cortisol levels. The regulation of the hypothalamic-pituitary-adrenal axis and the beneficial effects observed on health parameters and quality of life allow mud-balneotherapy to be classified as eustressful stimuli useful in preventing stress-related pathologies in healthy individuals and in alleviating symptoms in patients with chronic conditions. Future research on the topic is advised.
ABSTRACT
Water temperature is one of the main abiotic factors affecting the structure and functioning of aquatic ecosystems and its alteration can have important effects on biological communities. Macroinvertebrates are excellent bio-indicators and have been used for decades to assess the status of aquatic ecosystems as a result of environmental stresses; however, their responses to temperature are poorly documented and have not been systematically evaluated. The aims of this review are: (i) to collate and summarize responses of freshwater macroinvertebrates to different temperature conditions, comparing the results of experimental and theoretical studies; (ii) to understand how the focus of research on the effects of temperature on macroinvertebrates has changed during the last 51 years; and (iii) to identify research gaps regarding temperature responses, ecosystem types, organism groups, spatiotemporal scales, and geographical regions to suggest possible research directions. We performed a comparative assessment of 223 publications that specifically consider freshwater macroinvertebrates and address the effects of temperature. Short-term studies performed in the laboratory and focusing on insects exposed to a range of temperatures dominated. Field studies were carried out mainly in Europe, at catchment scale and almost exclusively in rivers; they mainly investigated responses to water thermal regime at the community scale. The most frequent biological responses tested were growth rate, fecundity and the time and length of emergence, whereas ecological responses mainly involved composition, richness, and distribution. Thermal research on freshwater macroinvertebrates has undergone a shift since the 2000s when studies involving extended spatiotemporal scales and investigating the effects of global warming first appeared. In addition, recent studies have considered the effects of temperature at genetic and evolutionary scales. Our review revealed that the effects of temperature on macroinvertebrates are manifold with implications at different levels, from genes to communities. However, community-level physiological, phenological and fitness responses tested on individuals or populations should be studied in more detail given their macroecological effects are likely to be enhanced by climate warming. In addition, most field studies at regional scales have used air temperature as a proxy for water temperature; obtaining accurate water temperature data in future studies will be important to allow proper consideration of the spatial thermal heterogeneity of water bodies and any effects on macroinvertebrate distribution patterns. Finally, we found an uneven number of studies across different ecosystems and geographic areas, with lentic bodies and regions outside the West underrepresented. It will also be crucial to include macroinvertebrates of high-altitude and tropical areas in future work because these groups are most vulnerable to climate warming for multiple reasons. Further studies on temperature-macroinvertebrate relationships are needed to fill the current gaps and facilitate appropriate conservation strategies for freshwater ecosystems in an anthropogenic-driven era.
