The paper cites this study, which substantiates these claims https://www.tandfonline.com/doi/pdf/10.1080/07853890.2017.1387927?src=getftr& https://www.tandfonli

The paper cites this study, which substantiates these claims https://www.tandfonline.com/doi/pdf/10.1080/07853890.2017.1387927?src=getftr& https://www.tandfonline.com/doi/pdf/10.1080/07853890.2017.13... Also on the topic of cheaper, at the end of the original paper is some evidence that hot baths offer similar benefits to saunas.