20 Frequently Asked Questions (FAQs)
- What are winter blues and seasonal affective disorder (SAD)?
- How common are winter blues and SAD?
- What is a circadian rhythm?
- What is light therapy?
- How does light therapy work?
- How much light is best?
- How can I compare light doses between different devices?
- What time of day is best?
- What type of lamp is best?
The best lamp provides:
Winter blues refers to a set of symptoms many people get in the short daylight months- typically September to March- including sadness, fatigue, decreased libido, difficulty concentrating, irritability, increased sleep and appetite, carbohydrate craving and weight gain. SAD is the severe form of winter blues, so that you become clinically depressed and the other symptoms become seriously debilitating. A key feature is that symptoms appear as daylight decreases in the fall and disappear as daylight increases in the spring.
As one might expect, winter blues and SAD are more common as you move further from the equator. Winter days are shorter and daylight decreases as you move toward the North or South Poles. Perhaps 25% of people in the northern US & Canada suffer from winter blues, with about 15-30% of these having SAD. People living in lower latitudes may also experience winter blues if they spend their days in offices that are typically much less bright than the outdoors, or if their winter weather is cloudy.
We all have an internal clock that determines our wake/sleep cycle, or circadian rhythm. This circadian rhythm normally matches our day/night cycle, but may be disrupted by jet travel across time zones, work shift changes (day shift to night shift and back again), or some insomnias where our sleep phase gets “out of sync”. When you circadian rhythm is disrupted, you suffer fatigue, decreased concentration and productivity, and increased work errors.
Light therapy is the shining of bright light into your eyes-typically for a half hour each session. Since the 1980’s, light therapy has become the first line treatment for winter blues and SAD. Bright light can also be used to shift your circadian (wake/sleep) cycle, so it is used to prevent jet lag, minimize work shift change fatigue, and help abnormal sleep phase insomnias.
We know that shining bright light into your eyes:
a) suppresses brain melatonin, causing wakefulness, and
b) enhances brain serotonin, causing mood elevation.
Light therapy takes advantage of these effects to alter your circadian rhythm to prevent jet lag and work shift change fatigue and some insomnias, as well as to treat winter blues and SAD.
Light therapy is measured in lux, which is measured of the intensity of light as perceived by our eyes. Typical room light intensity is several hundred lux. Light therapy began years ago with what we now consider to be low doses-500-2500 lux- for 1-2hours. Studies showed that treatment times can be reduced by increasing the light dose. Now, 10,000 lux for ½ hour is considered by many to be a standard dose. The Feel Bright Light brackets this “standard dose” by providing 8,000 or 12,000 lux so you can adjust to surrounding light conditions while receiving a very effective dose.
Each device manufacturer publishes the intensity of their device (usually in lux) as measured at the recommended distance from your eyes. So, the lux from a portable device that is 1-2 inches from your eyes is comparable to the lux of a desk-top device that is 18 inches from your eyes, etc.
For winter blues, a bright light session shortly after arising in the morning works best for most people. Some people benefit from an additional session in the late afternoon. Bright light use in the evening may disrupt your sleep pattern. For circadian rhythm shifting, i.e. jet lag, shift work, and sleep phase insomnias, the time of day to use bright light depends on whether you want to shift your circadian clock forward or backward.
- high intensity;
- maximum blue-to-green spectrum;
- focused light to make the best use of the available light;
- long life;
- small power requirement.
Reasons to consider bright light:
Most people with winter blues are likely to respond well to light. If your symptoms are severe, you may suffer from SAD. Light therapy may work well for you, but you should consult with your clinician before choosing any therapy. Bright light can be used along with other treatments- e.g., antidepressants for SAD. Likewise, most people will respond to light for circadian rhythm adjustment- i.e., jet lag, shift change work, and some insomnias.
Reasons to not use light:
Generally, bright light is very safe. If you:
a) have any eye disorder (e.g., cataracts, glaucoma, retinal disease),
b) have any disease with high risk for eye problems (e.g., diabetes, lupus),
c) have any problem triggered by bright light (e.g., migraine),
d) take photosensitizing medication (e.g., certain psychiatric drugs, melatonin), you should consult your clinician prior to starting bright light sessions.
No. You should let the light be in your peripheral vision field- preferably above your line of sight, so the bright light hits your lower retina for the best effect. Some clinicians recommend occasional looks directly at the light for brief periods.
The positive effects of most light therapy studies have been done with the eyes open. The standard 10,000 lux for ½ hour session assumes your eyes are open.
Reported side effects from bright light are generally uncommon and mild. They include:
a) nausea-which tends to pass quickly as light is continued
b) headache, eye strain, agitation, insomnia-which is usually controlled by decreasing the light dose or altering the time of day that the light is used.
Bright light at 10,000 lux is within the range of light we experience almost every day- from a dimly lit room of 100 lux to a sunny day outside of 40,000 lux. Eye exams of subjects receiving up to 20,000 lux have revealed no risks. Bright lights may cause some people to “see spots” for a short period after use. These “spots” normally disappear within a few minutes. Elderly people may take longer-up to 10 minutes-to return to normal.
Many studies have been done over the years that yield information about various aspects of phototherapy. Light effectiveness for winter blues and circadian rhythm shifting is well established.
In addition, research is now looking at using light for:
- non-seasonal depression
- post-partum depression
- pre-menstrual syndrome
- chronic fatigue syndrome
- ADD, ADHD
- sustained wakefulness
- substance abuse
Although clinicians increasingly understand and prescribe light therapy, there is, as yet, no light device that has completed the FDA process. Since light therapy is relatively new, insurance coverage is spotty. A claim may be initially rejected, but upon further explanation, may be covered. Medicare does not routinely cover such devices. Expect coverage for SAD to improve as insurance companies learn that light therapy is far less expensive than antidepressants.
Most desk-top devices provide 10,000 lux and are effective. If you can sit in one place for a half-hour each morning, a desk-top device may work well for you. However, you may find it much more convenient to do your normal daily activities while receiving your bright light sessions. A portable device may be the only way to achieve your goals and stay with a light program. Many people own both a desk-top and a portable device, and they use either under different circumstances.
The effect of light is prompt-hours to days, generally not weeks or months. For jet lag and shift change fatigue, the light is used to prevent symptoms before they actually occur.
For winter blues, most people use the lights daily each winter until the symptoms abate as days lengthen-typically in March or April.
For jet lag, the bright lights are used prior to the trip
For shift change fatigue, the lights are used prior to changing shifts.
For sleep phase insomnias, the problem may be long-term for the elderly, but teens tend to “grow out of it”
No. The Light may be safely used while doing many daily activities, but should not be used while driving or operating equipment. Depending upon the background light, it may be difficult to see well beyond the lights mounted on your visor.