April 02--Sleep is defined as a natural periodic state of rest for the mind and body, in which the eyes usually close and consciousness is completely or partially lost, so that there is a decrease in bodily movement and responsiveness to external stimuli. It is a state which accentuates growth, and rejuvenates our all-important immune, nervous, skeletal and muscular systems. Short-term or acute sleep deprivation can increase blood pressure, stress hormones, daytime sleepiness, make one irritable, cause fatigue and headaches, and decrease productivity at work. Chronic sleep deprivation can impair glucose tolerance, which can lead to diabetes. Among the many side effects of poor sleep are that the body craves high-calorie, high-carb foods, disrupting its ability to know it has had enough food. This in turn can be the cause of unexplained weight gain. The National Institutes of Health (NIH), US, suggests that healthy adults need about 7-8 hours' sleep a night. Of course, we would all love to get a good night's sleep, but certain factors interfere with the process. One of the common sleep disruptors I have observed in my practice is sleep apnoea. Typically, a wife comes along to complain of disturbed sleep because her husband snores. When snoring occurs -- it is very often a symptom of sleep apnoea -- a person doesn't even realize he or she is having difficulty in breathing. Such people are very often overweight, even obese. In a detailed question-and-answer session, they often disclose that they do not wake up fresh even if they have slept the adequate number of hours, tend to dose off in the day, and are always tired. I have seen many such patients take a snooze in my waiting room. Now imagine if this were to happen while driving. If you know any such person, please advise him to consult a doctor, who may prescribe a sleep study to rule out this condition. In mild cases of sleep apnoea, some changes in habit, like sleeping on one's side, avoiding alcohol and taking sleeping pills occasionally under medical guidance, can help. "Exercise, alcohol, nicotine, caffeine, painkillers, and heavy and spicy foods should be avoided before bedtime" Certain non-medical and environmental conditions too are not conducive to sound sleep. It is a good idea to dim the lights an hour before bedtime. The pineal gland, located in the middle of the brain, releases a sleep-inducing hormone called melatonin, more so when you are in the dark or in not very bright area. Use blackout curtains to create darkness, if need be. Many of us sleep with the phone/iPad/digital clock/television near us. This is a not a good practice. The short waves of the blue light interfere with sleep, so it is best to turn off all gadgets or at least cover the light that emits from them when you are ready for bed. Exercise keeps the body active, and hence should be avoided for 3-4 hours before bedtime. It is best to avoid alcohol and stimulants like nicotine and caffeine 3-4 hours before bedtime. Be careful of the other sources of caffeine, such as chocolate, colas, tea, and decaffeinated coffee, even some painkillers, weight loss pills, and cold medication. Avoid heavy, spicy foods at dinner because these can cause acid reflux, which gets worse when one is lying down and can, therefore, keep you up at night. Another common cause of sleep disturbance is jet lag. Our biological clock regulates the "normal" awake and sleep cycles in response to light, temperature, hormones, etc. Changes in these make people sleepy when they want to be awake. That is why, when we cross time zones, we experience jet lag. Try melatonin supplements for jet lag to reset your body clock. People working in night shifts, like those in call centres, pilots, air staff, doctors and the like, who keep awake at night, face the same problem. The body's natural clock is tuned to sleep at night, so though these people can sleep in the day, their body clock naturally slows down at night. People with such jobs try and "sleep it off" over the weekends but remember, it is the quality, not quantity, of sleep that is important. While even slight sleep deprivation can affect one's ability to think properly and slow down response time, cumulative sleep deprivation affects immunity and even cardiovascular health. Now that we know what to avoid, let's see which foods can help induce sleep. · The best foods to eat at night are high in carbohydrates and calcium (as they increase the sleep-inducing amino acid, tryptophan) and medium to low in protein. Foods high in sleep-inducing tryptophan are bananas, turkey (have it with bread), nuts, figs, dates, walnuts, yogurt, milk, tuna, cheese and wholegrains. · Cherries are naturally high in melatonin, a hormone that makes you sleepy. · Chamomile tea is a good relaxant and is useful for people with insomnia. · Bananas are high in magnesium and potassium, the two minerals that promote muscle relaxation. In fact, magnesium deficiency is related to the restless leg syndrome and night-time muscle cramps, both of which can interfere with sleep. So, eat a banana a couple of hours before bedtime. · Spinach is high in magnesium, potassium and calcium. Calcium is one more mineral which plays an important role in inducing sleep. Calcium helps generate melatonin, which helps maintain the circadian rhythm. Other greens that are high in calcium include kale and collard leaves and turnip greens. · Dairy is high in calcium, so our grandmothers got it right when they advised a cup of warm milk at bedtime. Don't just reach out for that addictive sleeping pill -- make changes in your environment and food. Vishakha Shivdasani is a Mumbai-based medical doctor with a fellowship in nutrition. She specializes in controlling diabetes, chol