A self-described cynic, Dr. Mary Neal had her view on spirituality radically altered during a near-death experience on a kayaking trip on a remote Chilean river in 1999.

With her capsized kayak pinning her under the surging water, Neal was believed to have not been breathing for anything between 15 and 25 minutes, according to the kayaking guides with her on the trip. During the time of what she terms her “drowning,” she claims to have had a heavenly experience in which she returned to God and was in the presence of Jesus and angels.

It was a life-changing event for a person who was not fervently religious. The incident also prompted Neal to write her best-selling book, ‘To Heaven and Back: A Doctor’s Extraordinary Account of Her Death, Heaven, Angels and Life Again,’ which spent several weeks atop The New York Times’ ‘Paperback Advice & Misc’ best-seller list.

Read an excerpt from Dr. Mary C. Neal’s ‘To Heaven and Back’

“I would never claim to have been particularly religious beforehand,’’ Neal told Matt Lauer during an in-studio appearance on TODAY Thursday. “I certainly believed in God. I think I was very typical. I sort of hoped there was something more and there was a reason that we were here, but I was very busy. I didn’t put spirituality in the forefront of my life.’’

A spinal surgeon from Wyoming, Neal suffered two broken legs and lung problems as a result of the incident, spending a month in the hospital and missing six months of work while in a wheelchair. As a doctor, she is used to having a biological explanation for near-death phenomena like bright lights and warm feelings, but believes this was a different situation.

“I absolutely would share those and would accept those because I am an absolute cynic and skeptic,’’ she said. “But my experience timed was a minimum of 15 minutes, and that didn’t include the five-plus minutes of figuring out that I wasn’t there, where was I, etc. When you look at a minimum 15, maximum about 25-minute experience, I don’t believe that can just be the chemical reaction of a dying brain. A brain can’t survive that long.’’

Neal claimed that she survived because she was told by God that her family would need her in the face of an impending tragedy and that the world needed to hear her story. She was told her son, Willie, who was 9 years old at the time, was going to die, but was not given specific details. In 2009, Willie was killed in a car accident at 19 years old in Maine by a male driver who was on his cell phone.

“I don’t pretend to have all the answers,’’ Neal said. “One of my kids would say I was kicked out of heaven. My primary mandate was not being here for my son’s death. My primary mandate was to return and share my story because my story is comforting and reassuring and inspires other people to really look at their own lives and find God working in their own lives.’’

She also is comforted by the notion that she will see her son again in the afterlife.

“I’m not going to pretend like I don’t wish he were here, but I’ll see him at some point,’’ she told NBC News. “I know that there is life after death, and I absolutely know that the promises of God are true.’’

Lauer raised the question of why Neal was able to return to life when many others die in similar situations, and she admitted that in the moment she did not want to return to life.

“I asked that same question many, many times because I have loved ones who’ve died, and I did not want to return,’’ Neal said. “Almost everyone I’ve talked to who’s had a near-death experience does not want to return. I felt absolutely like I was home. Not just at peace – I had returned to God’s kingdom and I was home.’’

Neal describes being in the presence of angels and Jesus as more of a feeling than actually seeing images of their faces, although she told NBC News she recalled seeing a large, domed structure.

“They were exploding with an absolute love,’’ she said about the angels. “They looked like compassion, even though that’s not an adjective. I’m embarrassed to say it now, and I wish I took notes, but I didn’t really note what they looked like or what I looked like because it didn’t matter. I wanted to get to this entrance to God’s kingdom.”

She believes Jesus helped guide her through the near-death situation before rescue workers were able to revive her.

“I feel very presumptuous saying that, but I believe that Jesus was holding me when I was still in my boat and reassuring me and comforting me,’’ she said. “He didn’t look like the image in my Sunday school books. I would say that I didn’t look at him critically in terms of saying, ‘What color is that hair?’ I looked at him and what I saw was infinite kindness and compassion.’’