People stretch their physical abilities all of the time. That's how you improve your fitness -- through increasingly difficult challenges. The same is true for dogs. You want to start small and work your way up to bigger and bigger challenges to get them in shape.
You don't want to push your trail dog too far too fast though. I often hear people say, "My dog will let me know when they're tired." What they don't understand is dogs will follow their people to the ends of the earth even if it kills them.
By the time your dog lays down and refuses to move, or collapses from exhaustion, it's WAY past the point at which you should have stopped. I've literally seen dogs collapse because they've pushed themselves as far as they could possibly go and, sadly, a couple of those dogs died. They literally ran themselves to death.
No one wants that to happen to their dog. There are many important and subtle signs you can watch for that will tell you when your dog is being pushed beyond their limits.
So how do you know if your trail dog has hiked too far?
It's normal for all dogs to pant a little, and breathe a little heavy, when they are exerting a lot of physical effort. However, if your dog is exhibiting one or more of these signs, they may be crossing the line into "this is too much for me."
1. Excessive Panting
This panting is often accompanied with a distended tongue. Drooling may or may not be present. If your dog stops drooling, it usually means they are dehydrated and that can be especially dangerous. (Note: this sign alone is usually not a problem -- just make sure your dog has plenty of water -- but, combined with another sign below, is a visual warning sign).
2. Very Heavy Breathing
If your dog is "heaving" when it breathes, or if its breath doesn't start to go back to normal after a 15 minute break, it's probably had enough for the day.
3. Lagging Behind the Group
Beginning to walk slow when they had been keeping up with the group, or were in front of it, is one of the first signs your dog is getting fatigued. By the time your trail dog slows down, it's best to turn around or already be on the way back to the trailhead.
4. Getting Wobbly on Their Feet
This could be a sign if dehydration, heat stroke, hypothermia, or much worse. If your dog is looks unstable on their feet, it's important to give them a rest and try to assess why.
5. Lameness or Limping
If your dog is suddenly limping (assuming you checked the pads of their feet for injury or debris), they probably strained something or something is starting to hurt from over-use.
It's important to understand that every dog is different, so you should get to know YOUR dog's warning signs. Even when you know your dog's limits, mistakes can happen. Hopefully there are no significant injuries to your dog if you go past the point that you should have stopped.
As with most things in life, you often don't know where a limit is until you reach it. The key is to learn from your mistakes and make changes for your dog in the future.
"Know your limits" (of both you and your trail dog) is the #1 rule of hiking with your dog in my book. If you know and respect limits, it will help to keep you and your dog healthy and happy for many more miles on the trail.
Has your dog ever been pushed too far? How did you handle that?