( CNN ) -- The people who died Thursday at a spiritual resort in Arizona had spent time in a `` sweatbox '' similar to what Native Americans and other cultures have used for prayer and purification rituals throughout history . Two people died and were 19 injured after spending up to two hours inside this `` sweatbox '' at an Arizona resort . And those who use them say they can be dangerous if care is not taken . From Scandinavia to South America to Africa , people have come together in the sauna-like structures -- typically heated by pouring water on hot lava rocks -- for a variety of reasons , said Joseph Bruchac , writer and author of The Native American Sweat Lodge . He 's part Abenaki , a tribe concentrated in the northeast United Staes , and part European . `` Each tribal nation has its own traditions , so one group might do it differently from another so you can not generalize too much , '' said Bruchac , who runs an outdoor education center in Greenfield Center , New York . In North America , most Native American tribes use the term `` sweat lodge '' to refer to a dome-shaped structure where the intimate ritual of the sweat takes place , said Bruchac , who has his own sweat lodge on his property in the foothills of the Adirondacks . `` Sweat lodges are typically used for a ritual preparation , like before a hunt , or nowadays , people might do it before a wedding or dance or some kind of community event as a way of putting yourself in balance , '' he said . Bruchac noted that incidents like the one in Arizona tend to raise discussion in Native American communities over whether non-Natives should be allowed to adapt traditional ceremonies . `` It 's a very meaningful ceremony . I can understand why people find it attractive , '' Bruchac said . `` But I consider it sacrilegious and foolish to do someone else 's rituals without proper guidance or practice , especially in sweat lodges where you 're raising people 's body temperatures . With that many people , oxygen is going to be depleted , and if you have heart problems or breathing problems , you could faint or die . '' No information about the sweatbox at the Angel Valley Resort near Sedona could be found on the Web site Saturday . The two people who died and the 19 others who fell ill there were attending a program by self-help expert James Arthur Ray , authorities said Saturday . Authorities said between 50 and 60 people were in the structure for nearly two hours -- far exceeding the number who ordinarily would participate in a traditional sweat , according to Bruchac . In a typical ritual , the leader of the sweat gathers four to 12 friends , family members or guests inside the structure , usually made of willow and covered with blankets or canvas , he said . `` The person running the sweat has to be very aware of the people in the lodge because he takes control of them mentally , physically and spiritually , '' said Bruchac . `` The leader is responsible for them , so he has to be aware of their physical conditions and their motivations , their reasons for being there . '' After everyone is inside , a firekeeper heats stones , usually lava rocks , and brings them into the lodge , placing them in a hole in the ground and carefully pouring water over the stones to release steam . The technique of releasing the heat is done with great care so that no one is injured by the steam , which can burn skin or lungs if someone inhales it , said Father Raymond Bucko , Director of Native Studies at Creighton University . `` Nobody will make it so hot that no one can stand it , '' said Bucko . `` Religious leaders are very careful about people 's health in the sweat . If they 're not healthy , people can sit outside the sweat and pray and others can go in for them . '' A ritual of speaking or prayer may follow , depending on the group 's intention for gathering . `` People talk and often there 's lot of humor , but at any time if it 's too hot , some one can say so and they will immediately open the door and people are encouraged to go out , '' he said . The Jesuit priest and cultural anthropologist participated in sweats with the Crow and Lakota people for nearly 30 years , until he was diagnosed with multiple sclerosis two years ago . `` It 's not about toughing it out or proving anything . It really is a beautiful experience of people coming together , of intense prayerfulness . ''
Sweat lodges are used in prayer and purification rituals across globe . Deaths raise concerns over non-Natives trying to adapt traditional ceremonies . Typical Native American sweat lodge used in ritual of prayer and purification . Comment: