Professional athletes are known for their game-day routines, whether its Sidney Crosby’s pregame peanut butter and jelly sandwich, Steph Curry’s shooting warmup or former Bears linebacker Brian Urlacher’s habit of consuming Girl Scout cookies before each game.

For Philadelphia Eagles offensive lineman Brandon Brooks, however, game days usually start with morning vomiting – a side effect of an anxiety disorder that he has battled throughout his professional career.

Brooks, who recently signed a four-year, $52.6 million contract extension — making him the highest-paid guard in the NFL — has been open and candid about his mental health, especially after his anxiety and the resulting nausea forced him to leave a game against the Seahawks on Nov. 24.

“I’d like to address what happened yesterday,” he tweeted after the game. “I woke up and did my typical routine of morning vomiting. It didn’t go away like it normally does, but I figured it would calm down once I got to the stadium. It did, but I felt exhausted. The nausea came back and I tried to battle through it and went out for the first drive. The nausea and vomiting came back until I left the field and I tried everything I could to get back for my teammates but just wasn’t able to do it.”

The physical symptoms of anxiety that Brooks experiences are very common, said Peter Lucchio, a psychologist at Hartford HealthCare’s Bone & Joint Institute.

“Anxiety often involves activation of the threat detection and management part of the body called the sympathetic nervous system,” Lucchio said. “The resulting physical symptoms may include nausea, difficulty breathing, tightness in the chest, racing heart rate, shakiness/trembling, dizziness, weakness in the extremities, increased perspiration, blurred vision or tunnel vision.”

Although many athletes experience some form of pre-game jitters or nervousness prior to competition, those feelings differ from an anxiety disorder, Lucchio said.

“Nerves before a game are normal,” he said. “Fear before a game might just be an indicator that they are excited or that the game is important to them.  The differentiating factor between pregame jitters and a formal anxiety disorder is typically the level at which it affects a person’s day-to-day functioning and if and how it permeates into other areas of their life.”

Although anxiety disorders can be debilitating, there are evidence-based treatments available, said Eric Lee, PhD, clinical psychology postdoctoral fellow at the Institute of Living’s Anxiety Disorders Center.

“Cognitive behavior therapy (CBT) is highly effective in treating anxiety disorders,” Lee said. “One to three months working with a CBT-trained therapist can greatly improve anxiety symptoms and overall quality of life.”

Over the past few years, many athletes have spoken out about their own battles with mental illness, including Brooks, Michael Phelps, Serena Williams, Brandon Marshall, and Kevin Love, sparking conversations about athletes and mental health. In his tweet after the game, Brooks was quick to squash any stigma around his anxiety.

“Make no mistake, I’m NOT ashamed or embarrassed by this nor what I go through daily,” he continued in the tweet. “I’ve had this under control for a couple of years and had a setback yesterday. The only thing I’m upset about is that when my team needed me, I wasn’t able to be out there with and for them.”

“This is a great example of someone being courageous enough to speak openly about his anxiety and the fact that he needs help,” Lee said. “So often, people suffer in silence for years or wait for their anxiety to become very problematic before seeking therapy.”

“This stuff is incredibly common and distinctly human – one in three people will have an anxiety disorder at some time in their life. We need to talk about it more and the fact that treatment can help.”

For more information on available treatments for anxiety at the Institute of Living Anxiety Disorders Center, click here.