Corporate hi-fliers who rarely step out without their data-loaded laptops will hate this, but doctors in Mumbai believe the device is a growing source of ill-health.

Tingling sensation in the fingers, strained tendons and sore shoulders are the price young and ambitious are paying for clicking non-stop on their laptops, according to a study done by occupational therapists in Mumbai.

"Busy office-goers are using laptops way over the recommended two-hour period," says S R Pingle of the Indian Association of Occupational Health, studying the habits of executives in two leading corporate houses.

The laptop craze is growing at an amazing pace in the Mumbai, especially after the advent of affordable brands a couple of years back. Corporate or self-employed persons can be seen glued to the LCD screen not just in airports, but even in crowded first-class compartments of trains.

Hep B-schoolers, jet-setting executives and self-assured corporate honchos refuse to step out to work - or even that cursory chotta sa break - without the convenience and connectivity of a laptop.

In the West, the dependence has grown even further. An international survey carried in Time magazine last week showed that one in five holidayers usually take their laptops along even on vacations.

The favourite excuse as the Mumbai study found was that essential office data is stored on the laptop. "Laptops are meant to be used for a short-time period, but executives are using them instead of their desktop computers in offices as well as homes," adds Pingle.

While the erudite crowd that logs on to laptops understand ergonomics (the science of fitting workplace equipment to maximise a worker's productivity), few seem to understand the damage done by excessive laptop usage.

Take Navi Mumbai resident Vijay Habbu (50), who is self-admittedly "laptop dependent". A senior executive in a corporate house, Habbu says he uses his laptop for over nine hours every day. "I had developed a ganglion (bunching of nerves) on my wrist, working on the computer, which got further aggravated when I shifted to regularly using the laptop," says Habbu. Nailing the diagnosis wasn't too difficult for him. "There was a clear correlation. When I was on leave and didn't use the laptop, I had no complaints," he says.

The problem is that laptops are not ergonomically designed to be used for prolonged hours. "The keys in a laptop are cramped. Moreover, most computer users haven't learnt typing and tend to use one or two fingers which puts pressure on the hand," explains Pingle.

Those who slouch over their laptops for long hours particularly complain of back and neck spasms or posture-related problems, says consultant and upper-limb surgeon at Bombay Hospital Parag Munshi. "Many also come in with strained tendons as their wrists are flexed in extreme positions," he says.

The Cornell University Ergonomics website has a basic explanation as to why prolonged use of laptops can be tough on the body. "The reason is simple - with a fixed design, if the keyboard is in an optimal position for the user, the screen isn't and if the screen is optimal the keyboard isn't."

Hearteningly, timely interventions can bring a lot of relief. "Since I can't work without my laptop, I always carry an external mouse which I attach to my system," says 45-year-old managerial executive Karunidhi.

Habbu, too, agrees that the move to an external mouse has given him 20% relief, though he still occasionally pops in pain-killers.

Doctors say preventive measures can keep away pain. "Such problems are usually caused by recurrent movements for prolonged periods. People should try and maintain the position of neck and back in neutral position," advises KEM Hospital's head of orthopaedic department Dr V J Lahiri. Munshi, who calls the laptop-related ailments "transient and temporary", says frequent users need conservative management which includes rest as well as "correct posture".