I Asked A Vet And A Trainer If Dogs Really Know When We're Sick, And Wow

Pets, particularly dogs, have been shown to pick up on their owner’s moods and even reflect their heart rate. Dogs, with their incredible sense of smell, can detect changes in body chemistry that may indicate illness. They can also observe changes in body language and routines, such as staying close and being more affectionate, when their owner is sick.

Full Article