The four cups a day addiction

The current British love affair with all things hot, frothy and caffeinated has been intense and passionate - much to the advantage of the coffee chains, which are opening cafes at a rate of one a week (Costa, the largest national chain, now has 100 cafes in London, 210 nationwide; Starbucks is close on its heels).

However, as with many love affairs, a year or so down the line, when the physical buzz is fading, you realise there's something unattractive lurking beneath that enticing exterior.

Increasing numbers of young London professionals, especially from the densely caffeinated areas of the City, are suffering from caffeine burnout. With 15 Starbucks, 13 Costas, and five Manhattan Coffee Companies in the EC1-4 area, not to mention the Pret a Mangers, Aromas and hang-ers-on, City workers are no longer reliant on the weak muck that is churned out by office coffee machines. Instead they are zapping their brains with two or three large lattes or several stiff espressos a day, and it's beginning to tell on their health.

Huw Griffiths, who runs the Complete Health Care Centre in Old Street, which offers acupuncture, reflexology and reiki, among other therapies, sees an increasing number of caffeine addicts. A little coffee is not a bad thing, says Griffiths. "Up to a point, the adrenaline buzz is good because it gets you going. It's the excess that is harmful. I'm shocked at the number of 25-year-olds we are getting here who are suffering from adrenal burnout." So how much coffee, and how often, is harmful? Received medical wisdom is that the minimum consumption which can lead to physical dependence is four cups per day, or around 400mg (there's 100mg of caffeine per 6oz cup). This is where the rise of the coffee bar has been lethal: if you've replaced three or four cups of Nescafe with the same number of lattes or cappuccinos, you're now drinking double what you used to - one dose of espresso contains twice as much caffeine as any instant blend.

What does caffeine do to you? Put simply, caffeine increases neurone activity in the brain, which convinces your pituitary gland that there's an emergency happening, so it triggers off the adrenal glands to produce adrenaline - the "fight or flight" chemical.

While this increases alertness in the short term, in the long term it can cause a reduction in fine motor coordination, breathlessness, the disruption of sleeping patterns, and head- aches, nervousness and dizziness. Eventually, you get caught in the caffeine loop - can't sleep because of it, can't go through the day without it.

The effect, says Griffiths, is adrenal overload: "Your concentration and short-term memory suffer. Then it leads to tightness in the chest, and then breathlessness and muscle pain. The trouble is, if you went to the doctor they would find nothing wrong, because you're not manifesting any real symptoms they can treat. But the fact is that your adrenals have gone into hyper phase. They are misfiring. They are delivering a charge when there's no need."

Costa Coffee London regional manager Ahmed Timor dismisses the idea that his City outlets are breeding caffeine addicts. However, he agrees that most City Costa cafes see customers more than once a day. "Ninety per cent are regulars, popping in two to three times a day. Increasingly, people have breakfast and lunch meetings there." Decaff is still not a popular option.

So what can you do if you think you're suffering from caffeine or adrenal overload? Cut out coffee, tea, Coke (50mg per 12oz can) and other caffeinated products - including chocolate (6mg of caffeine per oz) - and learn to relax, whether through gentle exercise, meditation, or even golf. The trouble is, the last thing most of today's high achievers want to do while at work is slow down.

That's where acupuncture and a change of diet can help. "You have to cut the angst and lift the energy through diet and overall lifestyle changes," says Griffiths.