Sniffing is one way dogs investigate those changes.

Can Your Dog Smell When You're Stressed?

Research suggests that dogs can distinguish certain odors associated with human stress under controlled conditions.

Stress can produce physiological changes, including changes in sweating and the release of chemical compounds. Some of these changes may affect body odor.

Dogs may detect differences that people cannot readily notice.

However, detecting an odor associated with stress is not the same as reading someone's thoughts or understanding exactly how they feel.

A dog that becomes attentive when its owner is upset may be responding to a combination of scent, body language, facial expressions, voice, and routine.

Smell may be one part of that response, but it is not the only possible explanation.

Can Dogs Detect Disease by Sniffing People?

Canine scent detection is an active area of scientific research. Studies have investigated whether trained dogs can identify odor patterns associated with certain diseases, metabolic changes, and other physiological conditions.

Some results have been promising, but performance depends on factors such as training, the odor being tested, and the conditions under which detection takes place.

A trained detection dog working in a controlled setting is not equivalent to a household pet casually sniffing its owner.

Your dog's sniffing is not a reliable medical diagnostic test.

If your dog suddenly becomes interested in one part of your body, that alone is not evidence that something is wrong. If you notice symptoms such as persistent pain, unusual swelling, unexplained bleeding, or a new lump, seek appropriate medical advice based on those symptoms.

What Your Dog's Sniffing Reveals About Your Relationship

Your dog recognizes you through more than your face and voice. Your individual scent is also an important part of how it identifies you.

When you arrive home, your dog may wag its tail, approach you enthusiastically, and sniff your hands or clothing before settling beside you.

Sniffing can be one ordinary part of interacting with a familiar person. It may help your dog investigate what has changed since your last interaction.