The summer months can be brutal to your dog.
Dogs are much more susceptible to heatstroke than humans.
One reason for this is, your dog wears his fur coat all year round. And while dogs do have sweat glands on their feet, they do not have them on the rest of their body. They rely on panting, a method of breathing out excess heat, to cool down their bodies. This method is not as affective as sweating. Some breeds are much more susceptible to the heat then others.