The oldest woman to climb Mount Everest said Friday she finally felt she had gotten old when she scaled the world's highest peak last weekend.

Tamae Watanabe, 73, beat her own age record for an Everest climb by a woman set 10 years ago. She also recovered from an accident in 2005 when she broke her back and feared she could never climb again.

"It was much more difficult for me this time. I felt I was weaker and had less power. This time it was certainly different, I felt that I had gotten old," Watanabe told reporters Friday on return to the Nepalese capital Katmandu from the mountain.

She reached the summit from the Tibetan side May 19, at the age of 73 years and 180 days.

That day, more than 200 climbers were aiming for the summit on the busier southern route in Nepal. Four died, apparently from altitude sickness and exhaustion, on one of the deadliest days on the mountain.

Watanabe said what surprised her, compared to her earlier climb, was the effects of warmer temperature on the mountain.

"There was a glacial lake formed near the base camp from the melting ice which our cooks could fetch water from," she said adding she is now encouraged to do campaign against global warming.

She now wants to help younger female climbers back in Japan to take up climbing high mountains.

The oldest Everest climber is 76-year-old Min Bahadur Sherchan of Nepal, who ascended in 2008.