UPDATED 2.08PM An adventurer with a rare brittle bone disease has died after suffering a head injury during a half marathon on Saturday.

39-year-old Samuel Gibson was on life support in Hawke's Bay Hospital in Hastings, and was surrounded by his family when it was turned off.

Mr Gibson spoke at TEDxAuckland last week about his experience with a rare and incurable condition called Osteogenesis Imperfecta.

He suffered a head injury while using a wheelchair to take part in the Sotheby's half marathon in Hawke's Bay.

Mr Gibson was surrounded by his family when he died.

He is survived by his wife Jen, and their two children.

Mr Gibson's brother Matthew has posted a statement about his death on Facebook.

"It's with heavy hearts and great sadness that we share with you Samuel's passing earlier this morning," the statement says.

"The family would like to publicly thank the ED and ICU teams at Hawke's Bay Hospital who were so kind in their care for Samuel. Unfortunately the injuries that Samuel sustained were not survivable.

"The family would also like to thank the many people who have been providing support for Jen, Rosa, Isabelle and his immediate family.

"Thank you also for the many kind messages of support that have been received. Samuel will be greatly missed by so many people, he touched so many lives and was an inspiration to us all.

OsteoHealth NZ owner Cath King considered Mr Gibson a "very inspiring person".

"I've seen how devastated people are when they have any kind of osteo diagnosis but then to look at Samuel and everything he did with his life, they can see that it need not define who they are."

Ms King is planning to post a tribute to Mr Gibson in the clinic's newsletter.

"I'd like to put a lovely message in which pays respect to him and shows our members the kind of life they can lead."

Meanwhile, Mr Gibson's running mate and friend Lisa Tamati has posted a heartfelt tribute on social media.

"We are lost for words and mourning the loss of our dear friend and wonderful human being Samuel Peter Gibson," she posted.

"We love you Sam you were a bright light for us and we honour you. Our thoughts are with Jen, the children and Samuel's family."