"Published in science journal PLOS ONE in March 2013, the study documented reliable core body temperature increases for the first time in Tibetan nuns practising g-tummo meditation...
"The researchers collected data during the unique ceremony in Tibet, where nuns were able to raise their core body temperature and dry up wet sheets wrapped around their bodies in the cold Himalayan weather (-25 degree Celsius) while meditating. Using electroencephalography (EEG) recordings and temperature measures, the team observed increases in core body temperature up to 38.3 degree Celsius..."
https://www.sciencedaily.com/releases/2013/04/130408084858.h...