A dog can watch another dog comfortably from far away, yet bark and lunge when that dog walks close. The change is often described as crossing a 'threshold': the point where the situation becomes too much for this dog at this moment. It is an observation to guide a safer plan, not a fixed line on a map.
Watch the whole dog
Notice whether your dog can move, sniff, look away and take a reward they usually want. A stiff body, fixed stare, attempts to retreat, growling or barking suggest the situation is getting harder. Refusing food can be another clue, but it can have many causes. Do not use one sign as a diagnosis. If your dog has bitten or may reach someone, keep a secure distance and get qualified behavior help. A sudden behavior change also merits a vet check.
Distance is one way to make an encounter easier. A barrier, quieter route or shorter exposure may help too. Noise, health, prior stressful events and the other dog's behavior can change what your dog can handle. If they become worried, calmly turn away where safe rather than asking them to sit through it. Dogs Trust advises moving away, using visual barriers and giving dogs space to relax.
Practice only when the setup is workable
On a quiet walk, note where your dog can observe a trigger without distress, then leave while they are comfortable. Use that information to plan an easier practice with rewards and a clear exit. Do not deliberately approach another dog to discover the exact meter where yours explodes. A qualified reward-based professional can help with a tailored plan, especially when lunging, bites or handling risk is involved.
Progress need not mean walking closer every week. It may look like easier recovery, a calmer route or more relaxed time outdoors. Management may remain useful long term. A setback does not prove the dog is beyond help, and a good session does not prove they are safe at a closer distance tomorrow.
Common mistakes
Calling a frozen dog calm because they are silent can miss fear. Treating a distance measured once as permanent ignores how conditions change. Pushing toward a trigger because a schedule says it is time may set the dog back. More space and a safer route are sometimes the whole solution for today. For more on applying that working distance across walks, see the leash-reactivity guide. It is not a fixed number of feet for every dog.
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Sources & care notes
Sources: Dogs Trust, 'Reactive dogs: why it happens and how to help'. VCA Animal Hospitals, 'Reducing Fear and Stress with Desensitization and Counterconditioning'.
A sudden change in behavior can have a medical cause. If something feels off, check with your vet first.
Frequently asked questions
What is a threshold?
The distance at which a trigger stops being watchable and starts being too much, often crossed suddenly.
How do I find it?
Watch the whole dog. If they can move, sniff, look away and take a reward, the setup is workable.
What signs say we are too close?
A stiff body, fixed stare, attempts to retreat, growling or barking. Reference distance from there.
Is distance the only tool?
No. A barrier, a quieter route or shorter exposure can help, and noise, health and history all matter.
