Many people workout at the gym in the pursuit of a different body - some lift weights to tone muscle, while others hit the treadmill in order to lose weight.
But when does exercise stop being part of a healthy lifestyle and start becoming an unhealthy obsession?
'Exercise bulimia' - where sufferers engage in compulsive exercise in order to 'make up' for calories consumed - is a seldom-discussed issue.
But with 640,000 people believed to be suffering from bulimia in the UK, it's about time this changed.
People who suffer from exercise bulimia count the calories they consume during the day, and later exercise in order to burn off this amount of calories or more.
It is not unusual for sufferers to binge eat food, only to put themselves through gruelling sessions at the gym to purge.
Writing for refinery29, former exercise bulimia sufferer Justin Sedor explains that exercise started to dominate his life: "At some point, working out stopped being about making me feel good - instead, I went to the gym so I would be able to eat whatever I wanted. Unsurprisingly, I became prone to bingeing. Somewhere along the way, working out became a very real way of purging myself of the sins I'd committed the night before."
Eating disorder charity Beat say that exercise bulimia "isn’t a recognised eating disorder", but they do not deny that the condition exists.
"It is probably coined from the over-exercising element we sometimes see in Bulimia Nervosa," Rebecca Field, a representative from Beat, told HuffPost UK Lifestyle.
Eating Disorder Foundation, which does acknowledge the condition explains more: "Exercise bulimia is similar to other forms of bulimia, except the individual uses excessive exercise as the predominant method of purging.
"Sometimes the individual believes what they are doing is OK because exercise is healthy. But in reality, they are ignoring the psychological and physical damage to their bodies."
Sam Thomas, founder and director of the charity Men Get Eating Disorders Too, agrees.
"Exercise Bulimia can sometimes go unnoticed because exercise is something that is seen as healthy but just because a person 'looks' healthy does not mean it is the case. Sufferers may compulsively exercise usually to lose weight unaware of the impact it has on their health."
So how much exercise is healthy?
Duncan Vincent from the Matt Roberts team at Grace Belgravia warned about the detrimental affect excessive exercise can have on the body.
"Exercise is essential for good health but remember that first and foremost it is a stress on the body and the way it functions. Healthy amounts of exercise can improve bodily function, but excessive exercise can cause problems.
"Overtraining is a physical, behavioural, and emotional condition. It can leave a person feeling extreme fatigue and affect motivation, and they could suffer from a decrease in exercise performance, insomnia, headaches and a weaker immune system," he said.
According to Duncan, overtraining can actually decrease muscle tone by causing the body to go into a catabolic state - the body starts to break down muscles for energy because it isn't fuelled for the exercise you are doing.
He added that calories should not become a focus: "Firstly it is very difficult to measure exactly how many calories we may burn every day and secondly the food we eat is about more than just calories.
"A low-calorie food that is packed with artificial sugars will be a poor fuel source, will make you feel lethargic and can actually lower your metabolism. A higher calorie-nutrient rich food source will be a great fuel source will improve your energy and can boost your metabolism."
Instead of calorie counting, he recommended a wide range of exercise to achieve physical goals.
"You should not just be focusing on what exercise will burn the most calories but asking: how can I make my body work and function to the best of its ability? To achieve this you need a variety of different types of exercise, mixed with different levels of intensity and volume," he said.
Eating disorders are both complex and unique, so what should you do if you recognise these symptoms in yourself or someone close to you?
In the first instance, Beat advise suspected sufferers to visit their GP.
"Eating disorders are serious – they claim more lives than any other mental illnesses but they are treatable. The sooner someone gets the treatment they need the more likely to make a full recovery," said Rebecca.
"If you’re worried about someone, don’t be afraid to approach them – they might be waiting for somebody to reach out. Don’t focus on food or exercising but tell them you’re worried and ask if there’s anything that they need to speak about, or that you’re there if they ever need to talk."
For more information, support and advice visit Beat's website.Suggest a correction