Assange, 41, whose website angered the United States by releasing thousands of secret diplomatic cables, took sanctuary in Ecuador's embassy in June, jumping bail after exhausting appeals in British courts against extradition to Sweden for sexual assault allegations.
Ecuadorian officials have said the former computer hacker is suffering from a chronic lung ailment as a result of his long stay in the embassy.
Dressed in a dark suit and white shirt fastened with silver-coloured cufflinks in the shape of a 'W' and an 'L', Assange showed no outward sign of health problems.
"The confinement, the circumstances are obviously difficult," was all Assange would say when questioned about his health by Reuters.
"I rather enjoy being swept away in the storm of it all. You only live once so it's important that we do something that is meaningful with our time," he said.
He is said to be living a cramped life inside the modest diplomatic mission. He eats mostly take-out food and uses a treadmill to burn off energy and a vitamin D lamp to make up for the lack of sunlight.
The whistleblower said he has used his time at the embassy to focus on his work, including a book "Cypherpunks" in which he warns that the growing amount of personal data we store online could render society a "slave to the internet".
Speaking in a gilt-corniced conference room, accessed via an entrance hall decorated with a beaming portrait of Ecuadorian President Rafael Correa, Assange spoke vehemently about the dangers of cyber-surveillance by governments and private companies.