I am a 57-year-old woman who has had a sleep problem for the last 30 years - since I got divorced, so I am well aware of the root cause. I usually don't have a problem falling asleep, but I wake up usually one hour later and then maybe an hour after that, and in the worse case, a couple of hours later; after this, I often can't fall back to sleep. Each time I wake, I feel I'm on auto-pilot and head straight for the fridge to eat something, usually sweet foods. I have absolutely no control at these times. Since I am borderline diabetic, I am very worried by what I eat at these times, as well as the fact that I do not get a good night's sleep and am very tired all day. Over the years I have tried almost everything, from sleeping pills to warm milk, brandy and herbal remedies - but none of these helped. I know about sleep laboratories, but since I find it very difficult to get to sleep anywhere other than my own bed, I do not think I would benefit from this. Where can I get help? G.D., Ashkelon Prof. Peretz Lavie, the country's most veteran sleep medicine expert at the Technion-Israel Institute of Technology medical school's sleep lab, comments: Your story is not unique or unusual. In many cases, insomnia that first started as a direct response to a transient stressful event such as a divorce takes on a life of its own and continues to fragment sleep for many years. Moreover, many times the patient, unlike yourself, cannot even pinpoint when the insomnia started and why. The transformation of insomnia from a transitional one to a chronic condition is mostly a result of a combination of factors sometime related to the mode of treatment or personality factors or a combination of both. Treatment is not easy and requires the patient's full cooperation. In your case, I would recommend a session in a sleep lab even if you can manage to sleep for only a few hours. This is needed to rule out any organic cause of sleep fragmentation. After that, a sleep expert can start a treatment regimen in an attempt to consolidate sleep and improve its continuity. I like to walk, run and ride a bicycle as exercise, but I live in Haifa, which is known to have high levels of air pollution. Is outdoor exercise recommended in this case? M.N., Haifa Prof. Joseph Cooke, an expert in clinical medicine and patient safety officer at New York-Presbyterian Hospital/Weill Cornell Medical Center, explains: It can be as dangerous to be outdoors behind a city bus - walking or bicycling - as it is to be in front of one. All the exhaust and smoke can damage health. Urban air pollution should be of special concern to those who exercise by running, bicycling or skating. While trying to benefit from exercise, they should take care not to harm themselves from exposure to air pollution. The main dangers are ozone, fine particulate matter and carbon monoxide (CO). These pollutants irritate the lungs and respiratory system and can exacerbate the problems of persons with underlying disease - such as asthma, bronchitis, emphysema or cardiopulmonary disorders. The pollutants affect the lungs by causing inflammation or irritation of the airway lining. More mucus and phlegm is produced and small muscles surrounding the airway respond by squeezing down, causing breathing to be more work and making it more difficult to get oxygen into the body. CO, which comes from cigarette smoke and automobile exhaust, has a tremendous ability to force oxygen out of the circulatory system because it binds with hemoglobin 200 times faster than oxygen. Overexposure may lead to headache, dizziness, confusion and dangerous increases in body temperature. Ozone, a large component of smog, results from the interaction of sunlight and chemicals in car exhaust. Ozone adversely affects one's breathing pattern and causes the airways in the lungs to become smaller and more resistant to oxygen exchange. Because of ozone, a person working out has difficulty taking deep breaths and has to breathe faster. As a result, the exercise becomes more stressful and difficult. If you have heart or lung disease, it's better to exercise indoors, especially during the summer months, and preferably in an air-conditioned room. If you must go outdoors, the early morning or evening is best because it will be cooler, the sun is not at its peak and the ozone levels will be at their lowest. If you do exercise outdoors, don't run on or near roads where there is heavy truck or bus traffic. If you experience any breathing difficulties, stop your exercise immediately and see your doctor. By taking these few simple precautions, you can make your exercise a wholly good thing and keep air pollution out of your body. Rx For Readers welcomes queries from readers about medical problems. Experts will answer those we find most interesting. Write Rx For Readers, the Jerusalem Post, POB 81, Jerusalem 91000, fax your question to Judy Siegel-Itzkovich at (02) 538-9527, or e-mail it to email@example.com, giving your initials, age and residence.