BROOMFIELD, Colo.– Sometimes, we take for granted the air we breathe. Dennis High doesn’t have that luxury.

“I do anything, any movements, the more strenuous, the worse it is,” High said.

Years ago, High noticed he was getting winded too easily. He says he would feel light-headed at times even doing simple tasks. He went to see a doctor.

“The doctor said, ‘Think of a normal air sac. Air just flows through it,’” High said. “And now, it’s like it’s trying to push your air through a piece of ply wood.”

High says doctors have diagnosed him with interstitial lung disease, which is an umbrella term for a group of lung disorders. High says they can’t pinpoint what’s causing his lungs to barely take in air.

“They know that my immune system is attacking my lungs,” High said. “They have no idea why.”

His condition keeps him tethered to nearly a dozen tanks throughout his house that vary in size. They are connected by a network of yards of green tubes. If he goes out of the house, High keeps one of the large tanks in his truck, which stands above four feet tall. He has five of them.

“Just as a man, you start to feel useless,” High said.

The medical mystery has landed him on of the lung transplant list. Regardless of the outcome, High has agreed to donate his lungs to science, so doctors can study what’s causing this for the 66-year-old Broomfield grandfather.

“They said that I [needed] this transplant a year ago,” High said. “What’s emotional to me is leaving my wife alone. And I think about my grandkids.”

Even if he gets a matching donor, High says the cost of treatment, medication and tests before and after the transplant could cost $180,000.

The High family has set up a GoFundMe page to help pay for the cost of this treatment,