Is it a good idea to measure stress?

It's summer and many people are planning a stress-relieving trip, while for many parents the school holidays are themselves a stressful time. But are we close to having a way for people to measure their own stress levels, and is this a good idea?

Everyone knows someone who is stressed out, whether it's over job worries, money concerns or personal problems.

Stress is notoriously difficult to define but measuring it could soon become official practice. The Office for National Statistics has been asked by Prime Minister David Cameron to assess the well-being of the population and has published details of a survey into what people think wellbeing embraces. It includes relationships with friends and family, job satisfaction, health and the state of the environment.

But aside from public policy, people can already measure their own stress without going to the doctor. Entrepreneurs are making money out of people's desire to test their stress levels. Devices are on sale that measure hormones, blood pressure or pulse rates.

Mitesh Soma, founder of Chemist Direct, is selling an executive stress kit containing monitors for blood pressure, body fat and cholesterol, and a pedometer, costing £100.

Soma's firm sells about a hundred a week. The former City worker came up with the idea after talking to ex-colleagues about health worries over long hours.

Plenty of other companies are trying to tap a lucrative market. US firm Affectiva plans to sell wristbands that measure the wearer's stress levels.

But even the term "stress" is divisive. For some it is the scourge of the modern 24/7 lifestyle, for others an ailment invented by therapists to medicalise normal human reactions. The accepted definition of being stressed - "experiencing physiological, emotional, or psychological stress" - did not appear in the Oxford English Dictionary until 1993.

But regardless of how people define stress, it has a huge economic impact through absence from work.

Helen McGill, who focuses on work-related stress for the Health and Safety Executive, says just under 10 million work days were lost to stress in 2009-2010 in the UK, across the public and private sectors.

"Stress is one of the biggest factors in absenteeism. We distinguish between pressure which can be a positive, motivational factor to you doing your job well, and stress which is the adverse reaction that people have to excessive pressure."

Stress may be big news but often patients aren't aware of its effect on their health, says the One Show's Dr Mark Porter. "The vast majority come in and look nonplussed when you suggest they're suffering from stress. But then as they talk about what's going on in their life, the penny drops."

The difficulty for doctors is there is no consistency in how people respond to stressful life events. Something one person might find extremely difficult, another would take in their stride, he says.

But is measuring stress a good idea? The firms selling stress kits say they can help people see what impact their lifestyle is having on their health and make appropriate adjustments.

Lynda Spain, a stress management consultant in Manchester, agrees that it's important to identify someone's stress level. Once she knows how stressed a client is she can take the next step and address it with cognitive behaviour therapy or other techniques.

But she doesn't use kits. "I like to ask people to visualise a stress thermometer. And ask them if the mercury is at bursting point at the top or if they're halfway up and things are starting to get too much."

Dr Porter says that trying to determine stress using quantitative measures is flawed.

High blood pressure might be related to stress

"I'm not a firm believer in a stress scale," says Porter. "The way I look at it is whether someone has a range of symptoms suggestive of stress: they can't sleep, they're underperforming, they're irritable or they're having anxiety attacks."

Saliva can be used to measure stress hormone levels, in clinical trials at least. And if you're stressed your pulse is likely to rise, as is your blood pressure. But it could be for lots of other reasons, too. Doctors do not take these results particularly seriously in regard to stress, preferring to look at someone's wider circumstances, Dr Porter says.

"Stress is a clinical diagnosis. It's similar to the way you don't have a blood test for depression. These kits may tell you something in isolation but they need to be interpreted properly."

Angela Patmore, author of The Truth About Stress, goes further. Self-testing is not just unreliable, it is harmful.

"The whole thrust of stress management is to medicalise what is a normal human emotion. It makes people become hyper-vigilant and anxious, and display all the symptoms of fear. They begin to examine themselves and start thinking they have a mental illness."

A prejudice has taken hold that people should be calm at all times. When people need a range of emotion over the course of a day in order to be "purposeful and creative", she argues. We should accept that our heart rates and pulse will rise, and we may start to sweat. Don't worry, it's a normal part of being alive, she counsels.

The people selling kits are taking advantage of people's vulnerabilities, Patmore believes. "It's trying to convince people they have a health problem and then selling them a solution."