Summer months provide the opportunity to keep our dogs in shape, improve their skill levels, and, perhaps, rectify shortcomings identified in the field last season. But you should remember to use the cool, damp mornings and be careful of the summer heat. Exhaustion can be a killer.

Retrievers, pointers, and other high-energy, athletic dogs have enormous enthusiasm for the job, often working to the point of self-injury. On hot, dry days, body heat builds up quickly in the active dog. And because they don’t sweat there’s no way to dissipate the heat.

The key is to recognize the warning signs of exhaustion early and to avoid training during the hottest part of the day. Warning signs include excessive panting, frothing at the mouth, lethargy, and dizziness. Some exceptionally driven dogs won’t slow down as they overheat. You’ve got to be exceptionally vigilant and stop training and cool them down with water.

Get the dog in shape before active training programs. If your dog has been out of service for a while or has become overweight and out of shape, begin conditioning with long walks practicing heel work and swimming retrieves on cool mornings. Swimming is more aerobic, easier on the dog’s joints, and cooler than running. Gradually extend the duration and intensity of the sessions getting the dog accustomed to working in warmer conditions.

Train in the early morning hours when the ground and air are cooler with less humidity. The dew is a bonus—much better than a sun-baked field. Involve lots of water work and choose places with a large tree canopy for shade. Plan sessions. Each exercise should have a training objective to prevent wasted energy, which builds body heat. Hold off long lining, casting, or pointing training for cooler weather. You can run four 25-yard retrieves with brief rest periods between each retrieve and keep the dog cooler than running one 100-yard retrieve.

This article originally appeared on Outside K9, the former dog blog of Outside magazine, on July 6, 2009.