It's often overlooked, leaving people feeling fatigued and hopeless, but some doctors have their doubts on whether it's a real condition at all.
Karen Powell, 57, knows the feeling all too well. She's a busy college president and said she's tired every day, all day.
"I couldn't sleep. I would gain weight. I was irritable. My hair and fingernails weren't right. My whole body felt like it wasn't right," said Powell.
That's when she turned to nurse practitioner Marcelle Pick, who wrote the book "Are You Tired and Wired?"
"We have too many people that are pushing the envelope too much, that are burning the candle at both ends," said Pick.
Pick, along with a growing number of medical practitioners, believes chronic stress has thrown our adrenal glands out of whack.
Stress activates the adrenal glands to produce cortisol, and cortisol regulates everything from blood-sugar levels, brain function and immune responses.
"I'm starting to see the issue of 'I'm so exhausted. I'm so tired' younger," said Pick.
Pick said she hears about women in their mid 20s and 30s describing the same symptoms, which includes needing caffeine to keep going, craving for sweets, a decreased sex drive or just feeling run-down.
But many in mainstream medicine haven't embraced the theory and said there are no studies showing chronic stress damages the adrenal glands.
For Powell, a saliva test revealed increased cortisol levels. She said focusing on healing her adrenal glands healed her.
"I learned to pay attention to what is it that I eat that makes me feel good, rather than eating to feel good," said Powell.
She cut out carbs and added protein and veggies. She takes calcium, Vitamin E and fish oil every day. And some people say licorice helps the adrenal glands.
Two years and 60 pounds lighter, Powell is glad she took notice of her adrenal glands.
"I have so much energy to do the work," said Powell.