Robert Hendricks, 77, had gone to bed with his wife Enid "Grace" at a relative's home in Ruskin on March 10 last year, the inquest in Bradford heard.
She went missing on the morning of March 11 and a helicopter search finally spotted her body clad only in a nightdress and slippers in a field just over eight miles from the house. She was pronounced dead on March 13.
Bradford Coroner's Court heard that Mrs Hendricks, a 75-year-old retired seamstress who was born in Jamaica, had Alzheimer's Disease.
Dr Patrick Waugh, a consultant pathologist, told coroner Roger Whittaker that he disagreed with an American autopsy report which concluded she had died from hypertensive heart disease.
He said: "I would say she has most likely died from a combination of exposure and dehydration.''
Mr Hendricks, of Martlett Drive, West Bowling, Bradford, said he heard her talking to herself in the night. He said: "When I woke up she was not there.''
Mr Whittaker recorded a verdict that Mrs Hendricks died accidentally and accepted Dr Waugh's view of the cause. He noted that after a long journey to Florida and meeting family she must have been very tired.
"During early morning the family noted a problem with the alarm system and that's clearly when she had left,'' he said.
Mr Hendricks said: "I miss her deeply – I can't sleep or eat properly. We were 48 years together. She was my wife and my best friend.''