Large Breed Longevity. The average lifespan of all dogs -- both small and large -- is 12.8 years, reports pets.ca, a Canadian pet information provider. Some larger dogs tend not to live that long, and data varies considerably by breed.
Aching Legs. Aching Legs and Feet. Injury is the most common cause of leg pain (aching legs). However, even a simple back pain can cause your legs to ache depending on the degree of pain. Usually, elders and diabetics and people with poor circulation are the ones who experience leg pain especially at night.
A strain is a common cause of leg pain and results from increased activity that leads to overstretching of a muscle. While muscle strains usually cause mild soreness, a person may also experience cramping, weakness, and swelling. More sudden or severe injuries can cause a muscle tear which is significantly more painful.