It's both cardio and sauna. The body adapts to these stimuli with greater heat adaptation, it's well studied in sports physiology. It works even better when car

It's both cardio and sauna. The body adapts to these stimuli with greater heat adaptation, it's well studied in sports physiology. It works even better when cardio is combined with heat: https://pubmed.ncbi.nlm.nih.gov/24444197/ https://pubmed.ncbi.nlm.nih.gov/24444197/