When is a dog considered a senior?

It's no secret that dogs mature much faster than humans. As they say, one year in your dog's life equals seven years in human life. So, exactly when is a dog considered a senior? Earlier than you think.

A dog is considered senior at the ripe age of 7 years old. And similar to humans, as dogs age, their energy levels shift and we need to reconsider their diet.

According to a survey conducted by Purina ONE, 31 percent of senior dog owners wished their pup had more energy, and one way to do that is by changing their food.

"Dogs' nutritional needs start to change when they reach age seven," Noa Hefer, Brand Manager for Purina ONE, said in a press release. "That's why Purina ONE Smartblend Vibrant Maturity is formulated with enhanced botanical oils to help promote mental sharpness, and high-quality carbohydrate sources like oat meal and whole grain wheat for healthy energy in senior dogs. You may even see an increase in average activity level over 20 percent when you feed it to your older dog."

The brand is currently pairing up with "Watch What Happens Life" host Andy Cohen and his rescue dog, Wacha, to promote the 28-day challenge. The challenge asks senior dog owners to switch their dog's food to Purina ONE to see improvements like more energy, a shinier coat, stronger teeth and better digestion in less than a month.

After the 28-day challenge, you can stick to the food to keep your senior dog healthy, or if you don't like the results, Purina ONE will give you a full refund for your purchase.

"I took the 28-Day Challenge when I switched Wacha to Purina ONE years ago, and absolutely saw a difference in his energy and coat," Cohen said.

"I’m excited to say that everyone who joins the 28-day challenge now at [Purina's website], Purina’s going to give a dollar for each person to the PetFinder Foundation, which is a fantastic organization that helps rescue centers and rescue dogs, and that includes senior dogs," he added.

Other ways to help keep your senior dog healthy include keeping them active by going for short walks or playing fetch, teaching them new tricks to keep their mind sharp, finding them a friend to run around with and looking into things like booties for extra traction on your hard wood floors or extra water bowls for around the house so they don't have to walk far.

You can learn more about Purina ONE's 28-day challenge here and get a coupon for $3 off.