Do Pets Know When You’re Sick or Upset?

Yes, pets do know when you’re sick or upset. Given their keen sense of smell, dogs can detect even the most subtle scent changes in our bodies when we are sick because the  biochemistry of our bodies change  when we're sick. Still, this doesn't mean that they perceive your condition exactly in the same way as you perceive it. Unfortunately, we can't interview them to understand what they think about our sickness or bad mood, but sometimes their behavior changes, especially if it is an adult animal who is very attached to you. If you are sick, cats try to lay near you or even on sore spot, and dogs don't pull their leash during the walk. 

Emotional

Pets are not just sensitive to biological changes, they can be sensitive to emotional changes too. If you are upset, a pet may come to you and just to be near you or leave you alone and stay at their place. One of the greatest emotions animals can detect is fear – in their owners and strangers.