US distance runner Gabriele Grunewald, who became an inspirational figure to thousands of fans after continuing to compete at a high level despite a decade-long battle with cancer, has died. She was 32.

Grunewald's husband Justin confirmed the news of his wife's death in a post on Instagram on Tuesday, two days after revealing her condition had deteriorated and she had entered end-of-life care.

"At 7:52 I said 'I can't wait until I get to see you again' to my hero, my best friend, my inspiration, my wife," Justin Grunewald wrote in the post, beneath a photo of the couple running.

" … I know I will never be able to fill this gaping hole in my heart or fill the shoes you have left behind," he added. "Your family loves you dearly as do your friends."

Gabriele Grunewald was first diagnosed with a rare salivary gland cancer in 2009, a year before she was diagnosed with thyroid cancer.