- Activity Levels
Another common symptom of sickness is a drop in activity level. Is your cat lackluster, distant or weak? Known diseases like arthritis will make your cat less active than they normally are. The activity level will drop further if the condition is life-threatening, so you just have to act really fast. There are instances when the opposite might also imply sickness, like when the cat exhibits excess energy or behaves erratically, find out why because there might be some underlying health concerns.