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.
Causes. 1  Main Causes. Muscle spasms cramps and strained muscles overuse account for most leg pain. 2  Muscle Cramps. Brief pains 1 to 15 minutes are often due to muscle spasms cramps. 3  Muscle Overuse Strained Muscles. Constant leg pains are often from hard work or sports.  Growing Pains. 10% of healthy children have harmless leg pains that come and go.