Dogs are not always great at indicating when they have had more than they can handle. Keeping a dog out on a walk can lead to exhaustion in the form of either generalized exhaustion or heat stroke, depending on the conditions. Because dogs are pack animals, they will push themselves to keep going long after it is good for them as long as you, a member of their pack, are continuing on. All dogs will slow down after enough energy has been used up walking and playing, but lethargy often takes the form of slow or uncoordinated movements, failure to respond to commands or names and even signs of dizziness, like stumbling. Exhausted dogs often seem almost as if they are different animals entirely, failing to respond to their name or commands and focused excessively on sniffing the ground. Of course, panting and refusing to get up are common indicators, but so are frequent lip licking and loss of interest. A dog that yawns frequently may be trying to recapture oxygen in order to rest, and your pet may even hide if they are suffering from exhaustion.