Only an appeal by his son persuaded him to continue.[302]
Despite Roosevelt's continued decline and loss of over 50 pounds (23 kg), Colonel Rondon reduced the pace of the expedition to allow for his commission's mapmaking and other geographical tasks, which required regular stops to fix the expedition's position by sun-based survey. Upon Roosevelt's return to New York, friends and family were startled by his physical appearance and fatigue. Roosevelt wrote, perhaps prophetically, to a friend that the trip had cut his life short by ten years. For the rest of his few remaining years, he would be plagued by flare-ups of malaria and leg inflammations so severe as to require surgery.[305] Before Roosevelt had even completed his sea voyage home, critics raised doubts over his claims of exploring and navigating a completely uncharted river over 625 miles (1,006 km) long. When he had recovered sufficiently, he addressed a standing-room-only convention organized in Washington, D.C., by the National Geographic Society and satisfactorily defended his claims.[302][page needed]

Final years
See also: Roosevelt's World War I volunteers
Former President Theodore Roosevelt in Allentown, Pennsylvania, 1914
Roosevelt returned to the United States in May 1914. 