“…The thermal effect within deep tissues can expand the blood vessels and promote blood microcirculation to eliminate metabolic toxins and waste [6,7]. Therefore, FIR textiles are always considered as an integration of therapeutic and thermal-protective segments, which have been widely used for various kinds of healthcare applications, such as warmth retention [8,9,10], relief from inflammation [11,12], wound healing [13,14], weight loss [15,16] and relief from aching pains [17,18]. Similarly, considering its physical therapy efficacy, the general requirements for FIR products in European and American countries are to assess a subjects’ blood oxygen content and flow velocity through a human wear trial over weeks or months.…”