1038 GMT February 28, 2020
Sprinting around trees, fallen leaves crunching underfoot, Valerie Stephan looks focused and peaceful on her morning jog, BBC reported.
"When I run, I feel like I'm achieving something," the amateur athlete said. "I'm getting faster, stronger. It's like a series of small victories."
Ten years ago, Valerie began jogging to improve her fitness. She signed up for a 5km (three-mile) run, followed by 10km races, then a marathon. But soon she was getting up early each morning to train — and prioritizing sport above all else.
"I started to realize that exercise controlled me, rather than me controlling exercise. That control quickly became an obsession," she said.
"It's had a big impact on my work, my family — every aspect of my life. Over time, exercise became unhealthy."
As the addiction grew, Valerie became increasingly isolated from those closest to her.
"It's damaged my relationships," she said. "Some people just didn't understand or see why I had to exercise. They saw me as a bit crazy."
Showing up late, rescheduling and cancelling became the norm. Valerie would arrange to meet up with friends on the condition they play squash or swim together, relaxing only when she had met her physical target for the day.
"They thought I didn't want to see them," she said. "I did but I had to train a lot beforehand or I would feel very guilty. It was like a constant trade-off."
Her obsession with exercise affected other significant relationships too.
"I could never rest. I was always escaping. I never wanted to spend time at home," she said.
"All I wanted to do was show that I was a superhuman who was totally in control — I couldn't show how difficult it was for me emotionally."
After years of pushing her body and her mind to their maximum, Valerie became depressed, burned out and in need of recuperation. She took four months off work to recover.
Psychologists said exercise addiction falls under the category of behavioral addiction, in which a person's behavior becomes obsessive, compulsive, or causes dysfunction in a person's life.
It is thought to affect about three percent of people, rising to 10 percent among high-performance runners.
Typically, those most vulnerable are amateur athletes, such as Valerie, seeking relief from internal distress, said consultant psychologist Dr. Chetna Kang, from The Priory Hospital in north London.
"Often people come to a clinic with a relationship breakdown, anxiety, depression, but as you start to unpick that, you realize exercise is the culprit," Kang said.
"It's not extremely common but it's becoming more so."
Symptoms of over-exercising include injuries such as stress fractures, tendinitis and a low immune system.
Women are at risk of what's known as the "female athlete triad", which includes loss of menstruation, osteoporosis and eating disorders. For men, intense exercise has been shown to decrease libido.
Martin Turner, a sports and exercise psychologist at Manchester Metropolitan University, has worked with and studied athletes for 10 years and regularly comes across people consumed by their athletic identity.
"They form the idea that their success as an athlete reflects their worth as a human being, 'I succeed as an athlete, therefore I am valuable. I fail as an athlete, therefore I am worthless,'" he said.
"Running is now part of who you are. If you don't run, who are you?"
Turner's studies show these kinds of ‘illogical beliefs’ are associated with greater exercise dependence, depression, anger, anxiety, and burnout.
"There are three main reasons these beliefs are illogical," he said.
"First, they hinder wellbeing rather than help it.
"Second, they reflect short-term and guilt-based motivation, where people run to avoid guilt, rather than running for its own sake.
"Third, they are not consistent with reality. You have to breathe, eat, hydrate and sleep. You don't have to run."
Withdrawing from the rush of adrenalin and endorphins released through sport can be particularly difficult.
For Valerie, attempts to reduce the amount of exercise she takes have had a strong impact on her wellbeing, often making her feel more restless. This, she said, keeps her locked in a vicious cycle.
"I feel really anxious when I can't train," she said. "I can't sleep, I get headaches. A day when I haven't been out exercising feels like I've been in prison, trapped."
Dialing down the amount of physical exercise she takes can be a challenge when surrounded by apps and wearable technology such as Strava, Garmin, FitBit and others.
"I love apps. I look at them every day, monitoring my pace, the volume of training I do, what progress I've made," Valerie said.
"You can get a lot of kudos, you see how you've improved and you can see what your friends are doing. But if I've got a marathon coming up and my friend is doing a lot more training, I feel pressure to get up to speed."
This access to data, sport psychologist Martin Turner said, can add to the obsession, becoming detrimental to recovery.
"Measurements give you an injection of self-esteem," he said. "The problem is that apps keep telling you you've fallen short. You're not as good as last time, you're not as good as your friend. You're constantly competing with others in a very outcome-driven way."
This is made worse if your self-worth is wrapped up with your exercise achievements, said Turner. "If my app tells me I have fallen short, and I also believe that 'when I fail, it makes me a complete failure', then this external judgement is even more problematic."
British Triathlon coach Audrey Livingstone said apps and wearables have led to an unhealthy attitude to exercise among the athletes she trains.