"Head above Water" is the first single from Avril Lavigne's sixth studio album, and the first new music she'd released since 2015's "Fly
." She hadn't released a studio album since her self-titled effort in 2013.
Lavigne wrote a letter to fans explaining that "Head above Water" is about her battle with Lyme disease, which can cause fatigue and joint pain, and is potentially fatal. She had faded from the public spotlight for a while because she was fighting off the disease. In bed and on the couch, she turned to writing music to get her through the situation.
"Those were the worst years of my life as I went through both physical and emotional battles," the singer wrote. "I was able to turn that fight into music I'm really proud of."