Dear Jim: My mood often seems to be down during winter with its shorter days. I considered buying an intense SAD light kit or a dawn simulator for waking. Do these use a lot of electricity and do they work? – Pam T.

Dear Pam: SAD (seasonal affective disorder) is how some physicians describe the winter blues. It is thought the shorter and less intense light during winter can have an impact on one’s mood. Some hospitals have SAD light therapy rooms where you pay a fee to use them for short regular visits.

You should always contact your personal physician for his or her advice about using any self-therapy. Physicians’ opinions vary on the effectiveness on light therapy. Continuous depression is a serious mental and physiological condition that always requires the consultation of a physician.

SAD therapy light kits are basically bright light boxes. The theory is the bright light on the retina causes internal effects that can alter mood and natural body rhythms. The light intensity is supposedly more important than the type of light. Some SAD lights use full-spectrum light tubes, which more closely simulate the natural light spectrum of the sun.

The electricity used to operate a SAD therapy light kit is not great because most use efficient fluorescent tubes. These lights are bright, but since you would have to have some lights on anyway, usually inefficient incandescent bulbs, you may actually save electricity in the long run.

Light intensity of 10,000 lux is considered to be the threshold brightness to be effective. As a reference, the natural brightness outdoors at noon on a sunny day is about 90,000 lux. You don’t have to stare directly into the SAD light. Use it for reading the newspaper (my column) in the morning.

Lux levels drop as you move farther from a light source. A good-quality SAD light should produce 10,000 lux at a distance of 18 to 24 inches. Weaker lights require you to sit too close for comfort. Some of the SAD lights are attractive with oak exteriors and others are portable with carrying cases.

Dawn-dusk simulators are used instead of an alarm clock to naturally wake you in the morning. This is how the sun shining through closed eyelids naturally wakes a person during summer. Simulators gradually brighten the light over an adjustable 15- to 60-minute period. They also include a backup alarm. Some simulators include a light and others control an existing bedroom lamp.

Other related products are battery-operated SAD light visors that are worn on your head so you can move around. These are sometimes used to combat jet lag and NASA has tested them during space travel. There are lighted window kits that mount on the wall to simulate a sunny window. They include changeable scenes.

Write for (instantly download – www.dulley.com) Update Bulletin No. 667. Include $3 and a business-size SASE and send to James Dulley, 6906 Royalgreen Drive, Cincinnati, OH 45244.