Ever since the first light bulb was switched on, human beings stopped regulating their working day by the movement of the sun. In 21st century India, in fact, the sun doesn't set for very many people. Doctors, nurses, paramedical staff, air-hostesses, those in the hospitality industry, journalists, soldiers and security personnel have long been facing difficulties associated with sleep deprivation. And with the growth of BPO (business process outsourcing) units and the software industry in an increasingly globalizing India, the numbers of sleep deprivation victims have swollen to grave proportions.

The lengthening list of psychological and physiological problems attributed to lack of sleep shows it can no longer be relegated to an occupational hazard that individuals must deal with on their own. Increasingly, we are beginning to understand the true role that sleep plays in maintaining mental and physical equilibrium and aiding growth. Studies show that while sleep - sound, regular sleep - is indispensable for men and women alike, on women, children and adolescents, the effects of sleep deprivation are especially virulent.

Any condition that causes a disturbance in sleep or leads to an individual being unable to complete his quota of required sleep is called a sleep disorder. The reasons are physiological as well as sociological, says Dr N Ramakrishnan, a certified sleep specialist and founder of the pioneering Nithra Institute of Sleep Sciences in Chennai.

"Contrary to the common perception of sleep as a passive state, where body and mind are at rest, it is an active process," he says. Sleep can be divided into various stages, including REM (Rapid Eye Movement) sleep and slow wave sleep. During the latter period, growth hormones are released, while the former is thought to be inextricably linked to memory and learning. Both are crucial for growing children.

And children are increasingly at risk. In modern India, where double incomes are a necessity, parents are forced to shake awake their infants to drop them off at childcare centers. As they grow, the pressure to excel in curricular and extra-curricular activities translate into coaching classes, growing workloads, exams, thus eating into sleep time, says Ramakrishnan.

"I make parents and children who come to me sit down and analyze how cutting down on sleep is actually setting back performance," he says. They find increased sleepiness during the day, poor attention and retention capacities and a performance dip, which triggers depression and more effort, prompting a repetitive cycle. As tiredness grows and productivity falls, emotional and behavioral problems also surface.

"After the elderly, among whom sleep disorders are most common, women have the dubious distinction of being the highest category of victims," says Ramakrishnan. He explains that, in India, the problem is compounded by the dual role society constrains women to play, as co-breadwinner and homemaker, without concession to added burdens.

And then there is the issue of subtle discrimination. "As a professional, I have to prove myself twice over," says S Chitra, Associate Editor with a leading Internet magazine in Chennai. While working as news editor in a prestigious national daily, she checked and re-checked material, conscious that her gender would be brought up, however obliquely, in the context of any slip-up. As a result, even when she wound up and went home, she found herself unable to wind down. Stress is a root cause of insomnia.

Chitra's disrupted sleep patterns led to a persistent feeling of listlessness. A general practitioner prescribed sleeping tablets, "but after an extended period, even the pharmacist refused to supply them to me," says Chitra ruefully. She had to seek a psychiatrist's help and will be happy if she can put insomnia behind her in another couple of years.

With India moving into a 24-hour society, she is no longer part of a minority. Lured by hefty pay cheques and projected glamour, thousands of young women join call centers, BPOs and software institutions. Staying up at work through the night, snatching an hour or two of sleep and then getting up to cope with household chores and family responsibilities, these women usually realize too late the damage sleep deprivation can do. "For about 10 years I abused my body, working on and on. I had no idea what it was doing to me," says Chitra.

Among the elderly, loneliness is a leading cause of sleeplessness, adds Ramakrishnan. Take the case of a patient who complained of progressive inability to sleep. Sensitive probing revealed that the problem started when her children had left home to set up their own families. Another growing issue in an increasingly nuclear, urban India.

Statistics culled by A C Nielsen - a leading provider of international market information - after a global study in late 2004 reveal that as many as 46 per cent of Indians sleep for less than six hours, 40 per cent go to bed between 11 pm and midnight and 64 per cent wake up before 7 am.

Inadequate sleep dulls the mind and generates neuro-cognitive problems. It has also been associated with heart disease, high blood pressure, diabetes and a significant weakening of the immune system. Fatigue is a common physiological symptom. Anxiety, depression and a poor response to emergencies are among behavioral fallouts of insufficient sleep.

The most common types of sleep disorders are Insomnia and Sleep Apnea, says Ramakrishnan. Insomnia is characterized by an inability to sleep, or abnormal wakefulness. Daytime symptoms include lethargy, irritability, frequent napping and attention deficiency. It would be wise to seek medical help if symptoms persist beyond four weeks, he advises. Sleep Apnea is characterized by brief cessation in breathing during sleep, and symptoms include loud snoring and excessive daytime sleepiness.

Sleep medicine is just 8-10 years old in the West, where there are some free-standing sleep laboratories with specialized personnel and equipment to diagnose the condition and rehabilitate patients with incurable sleep disorders. In India, it is in an embryonic stage. Though some lung- and ENT (ear-nose-throat) specialists take cognizance of it, not much attention is paid to the subject as a specialty. Research is poor and data sparse, says Ramakrishnan.

It is to fill this gap that he set up Nithra in 2004, as an institute for diagnosis and management of sleep disorders, and also to train doctors and paramedical personnel in this emerging specialty. "Our mission is to promote awareness of sleep disorders, in particular, the importance of early diagnosis and treatment," he says.

So, how much is sleep is enough? There is no categorical answer. Each individual's needs are different. Some thrive on five to six hours of sleep, while others need eight to nine hours. Women tend to sleep a little more than men, adolescents need more sleep than adults and older people a little less than younger ones.

To correct poor sleep habits, Ramakrishnan recommends practicing sleep hygiene - undertaking relaxation methods, controlling the sleep environment, avoiding large meals or strenuous exercise just prior to going to bed and reducing, if not eliminating, intake of alcohol and stimulants like caffeine and nicotine. "With growing awareness will come increasing availability of help," he promises.