Adam Holt, 34, recently wrapped up two years spent researching the link between fitness and addiction as a grad student at The University of Texas. It’s been a challenging experience, he easily admits, but it’s led him to understand the potential for exercise to help people in recovery.
“There’s a lot of science behind it,” Holt says. “All of these things come together in fitness to help someone stay sober.”
Holt finishes his studies at a time when substance use disorders (SUDs) — occurring when recurrent drug or alcohol use causes health problems, failure to meet responsibilities in places such as work, home or school and other issues — are affecting a consistent number of American adults.
About 19.7 million people aged 12 or older had an SUD in 2017, according to data collected from the National Survey on Drug Use and Health that year, and in 2016, that number sat just a bit higher at 20.1 million.
More than four million individuals received treatment for substance use in 2017. But treatment isn’t a guarantee of sobriety — 40 to 60 percent of individuals with SUDs relapse, according to the National Institute on Drug Abuse.
Holt has focused on this population during his time at UT. He has assisted researchers studying the benefits of fitness to prevent relapse and says recent studies — especially those evaluating fitness’s neurological effects — have made him confident that it is a method that works.
“There is this connection,” Holt says. “Fitness and physical activity can reduce relapse rates in people struggling with substance use disorders.”
While there haven’t been many clinical studies done on this relationship, as it’s more difficult to conduct tests on human subjects, animal-based studies have shown that there is biological basis for protective, anti-relapse effects of exercise, says Wendy Lynch, an associate professor of psychiatry and neurobehavioral sciences at the University of Virginia.
Some of the first of these animal studies were conducted about 10 years ago by researchers such as Mark Smith, a psychology professor at Davidson College. Smith, through rat-based studies, determined that a previously understood relationship between increased exercise and decreased drug use was in large part driven by exercise reducing the rewarding effects of drugs.
In his studies — the first of which were published in 2008 — Smith exposed rats to aerobic exercise (a running wheel), and found they self-administered fewer drugs than sedentary rats.
“They self-administer less cocaine, I’ve shown,” Smith says. “They self-administer less heroin. Other researchers have shown that they self-administer less nicotine, less methamphetamine and pretty much every other drug as well.”
This could have happened for a few reasons, Smith says. Exercise can serve as an alternative non-drug reward, providing something pleasant to do as an alternative to a drug. It can also reduce anxiety and depression — both risk factors for substance abuse, he says.
Neurological effects of exercise factor in as well, according to both Smith and Lynch.
Lynch focuses on these effects in her research, which involves studying changes in glutamatergic signaling in the cortex of the brain. Increases in glutamate, an excitatory neurotransmitter in the brain, is believed to trigger craving and lead to relapse, she says.
“These glutamatergic pathways become hyperactive when a person has gone through withdrawal or an animal has gone through withdrawal, and then they come into contact with, say, a cue that’s associated with the drug use,” Lynch says, using smelling a drug as an example of a cue. “That’s going to trigger intense craving, and that’s due to the glutamatergic signaling in the cortex.”
Her rat-based studies, the most recent of which are currently in press, have shown that exercise during early withdrawal can normalize glutamatergic signaling and prevent that hyperactivity — and craving for a drug — seen later.
In addition, Smith says exercise can lead to increased levels of dopamine, a chemical in the brain that’s related to the rewarding effects of drugs.
“We know that most drugs of abuse in the short term increase dopamine, and that’s largely responsible for their rewarding effects,” Smith says. “Well, short bouts of moderate exercise also increase dopamine. So, you can kind of get your dopamine fix (through exercise), and that’s kind of an oversimplification, but it’s not inaccurate.”
Both Smith and Lynch also point to a human-based study from 2016 in which participants, adult men and women with methamphetamine dependence, maintained abstinence for a period of time and then were exposed to exercise.
The study found dopamine D2 receptors, which are decreased over the course of addiction, are normalized by exercise.
These neurological effects stood out most to Holt from his research. He says these findings provide the most convincing evidence to him that exercise can be used as a treatment for addiction.
“If you can show that there’s actually something that happens biologically, in the brain…if you can show fitness increases the dopamine receptor sites, then there’s no question — it’s not like, ‘Oh, it will kind of make you feel better,’ it’s, ‘No, fitness will do this,’” Holt says.
Holt’s choice to study these effects in grad school was motivated by experiences in his own life. He struggled with drug abuse and addiction for many years in high school, college and even during his time spent in the military.
It led Holt to a point at which, he admits, “I didn’t like who I was.”
Holt’s first experience with drugs was at his 16th birthday party, when someone offered him liquid ecstasy. He says he was hooked on the feeling of acceptance it gave him — something he chased after in the years that followed.
He attended college at Texas A&M University, where he joined the Corps of Cadets, but also began regularly drinking and smoking weed. By his junior year, he had started using cocaine.
When he joined the Army Reserve and got married, Holt was still using. Despite a few scares in the military, Holt never faced serious consequences for his drug use.
It was an addiction to methamphetamine, which he developed after he returned from deployment in Afghanistan in 2011, that changed everything for him.
“Everything just sort of starts to unravel,” Holt says. “Because I want this drug.”
In the years that follow, Holt was divorced, had gone to jail three times and attempted to commit suicide. He lost his house and a connection with his family.
In winter 2015, stopping at a hotel on the way to collect his things from a sober home (he’d been kicked out of for using), Holt finally realized how alone his addiction had left him.
“I was in this hotel room. It was just me and a bag of Arby’s, and I had no one to call. I had no one, nothing,” Holt says. “That was the bottom of everything.”
After that day, Holt began to look for ways to rebuild his life. He went to his third treatment center and stayed in a halfway house. Then he got a job at The Cheesecake Factory and an apartment through a nonprofit.
These things helped Holt stay sober, but periodically, he would still relapse. That’s when he started working out — something he says helped him maintain sobriety for longer periods of time.
“I saw a correlation. When I was active a couple of times a week, it was easier for me to stay sober, because I was enjoying life,” Holt says. “I quickly noticed that when I wasn’t working out, I wasn’t happy, and I was relapsing.”
At first, Holt lifted weights and ran at a gym close to his apartment. Later, he got involved in Spartan races — extreme obstacle course races that require participants to carry sandbags, crawl under barbed wire and climb ropes in order to complete them.
While exercise wasn’t a cure-all, he says it gave him something to focus on other than his addiction. He also says his research at UT has helped him understand the science behind how exercise could have potentially benefitted his recovery.
Now, Holt has been sober for over a year. He has a partner, a son and, as of May 25, a graduate degree. He’s also turned his attention toward a new goal: building a sober community in Austin through free fitness programming.
“We really want to make something community-focused and show the recovery community that there are people there that want to partner with them,” Holt says. “The only requirement for coming to any of our classes is 48 hours of sobriety, so I mean, in theory, it’s really for anybody.”
While he’s still getting his nonprofit, Outsiders Anonymous, off the ground, Holt says he’s led fitness classes in a few sober homes and treatment facilities. He is working toward having a facility of his own, where he can offer workout classes and a place for Austin’s sober community to gather.
He says both his own experiences and research have made him confident that the recovery community could benefit from his initiative. People will consider exercise as a method of recovery, he says, “because they want to stay sober.”
“The data is there like, ‘Yes it helps, yes it works. This is another tool that you can use as a part of your recovery,’” Holt says. “We just have to be able to provide these services.”