Sauna is worldwide one of the morst popular methods to spring-clean the body and purification. To have a sauna is mainly used for hardening the body against caughts and sneezes and can be used within some deseases as theraputical application, e.g. within disorders of the autonomiv nervous system. 
cocowell supports the body in a holistic way in his detoxification and purification and brings the minerals, which were lost in having a sauna back to the body and rehydrates the body. In addition, coconut water is a cold drink in asiatic theory of food - so it cools the body from inside.