There are lots of things that human beings can get addicted to, some of which are more dangerous and destructive than others. From nicotine to alcohol, cocaine to chocolate, in the modern free-market economy and information age we are surrounded by temptations that can take over our time, money and health.
A lot of people, perhaps instinctively or through social experience, recognise these temptations and their weaknesses and either learn from or manage their potential addictions; they moderate their drinking, steer clear of the chocolate aisle in the supermarket or actively disassociate from social circles where Class A drugs may circulate.
They recognise the risks within themselves and protect themselves from potential danger.
In my experience, most people navigate the middle road in life where addictions and behaviour is concerned and thus stay out of trouble. But what happens when a potential addiction comes wrapped in what seems to be a healthy lifestyle? Or, to put it another way, what happens when the exercise gets to be addictive?
Most people who work out regularly and who see the effects and results of such exercise will know what I am alluding to here.
When you are in the position of getting a buzz and/or compliments from putting in the time at the gym (or pounding the pavement) it can be a powerful driver to do more and to immerse yourself in the fitness lifestyle. For certain people, however, this concentration on and absorption in exercise can go further and encompass an addiction to the biochemical processes at work when we workout. In these circumstances, exercise itself can become as stimulating, as dominating and as inescapable as any narcotic.
It can also be just as dangerous.
Runner Valerie Stephan has vividly documented the effects of exercise addiction on herself and how over a decade it came to dominate her life. "I started to realise that exercise controlled me, rather than me controlling exercise. That control quickly became an obsession," she says, speaking to the BBC about her problem. "It's had a big impact on my work, my family - every aspect of my life. Over time, exercise became unhealthy."
As her addiction grew, Stephan became increasingly isolated from those closest to her. "It's damaged my relationships," she says. "Some people just didn't understand or see why I had to exercise. They saw me as a bit crazy."
Typically, those most vulnerable to such a compulsive addiction are amateur athletes, such as Valerie, seeking relief from other distressing aspects of their lives, according to consultant psychologist Dr Chetna Kang. "Often people come to a clinic with a relationship breakdown, anxiety, depression," Kang says. "But as you start to unpick that, you realise exercise is the culprit."
It is believed that around 3% of the population is affected by what such psychologists characterise as an obsessive behaviour (with this figure rising to 10% for high-performance runners). For myself, I recognise this correlation.
Being a champion of running, I have spent a fair amount of time on treadmills and sprinting around race tracks. I advise people to run when they can and that gym-goers should add regular time on a treadmill for the benefits it gives to a typical workout. But I also recognise the compulsive edge that running can come with and how powerful this can be if it is not controlled.
And then there is the rush that adrenalin and endorphins give you when they are released through sport, which can be particularly stimulating. You feel it when you run, in a powerful and meaningful way. It is a rush and one which you want to experience again and again.
Symptoms of over-exercising include injuries such as stress fractures, tendinitis and a low immune system. Women are also at risk of what is known as the ‘female athlete triad’, which includes loss of menstruation, osteoporosis and eating disorders, whilst for men, intense exercise has been shown to decrease libido.
If you recognise these signs of exercise addiction in yourself, the first thing to do is to consider what your relationship to the behaviour is and why it exists. We are not cogs in a machine, driven by motivations and workout data, but rather are sentient beings that are part of a network of actions and processes, not all of which we control. Understanding that reality and the drivers behind our behaviours is one way of bringing our behaviour into balance.
The other thing that anyone who feels they are becoming addicted to exercise should do is to talk about their motivations, experiences and concerns with someone who is experienced, knowledgeable and who can help. A fitness expert, who has worked with people who have been so motivated, made progress and suffered an injury will be able to empathise, advise and lead the way to a healthier and more sustainable fitness future.
We are rarely alone when we exercise unless we choose to be so. But if we choose to reach out to the fitness community, to both its professionals and amateurs, we stand a better chance of advancing with a healthy fitness lifestyle, rather than getting addicted to its thrills and the spills, which may one day either injure or kill us.