Morning Bright Light Research Articles

Advancing Circadian Rhythms Before Eastward Flight: a Strategy to Prevent or Reduce Jet Lag

Study Objectives—To develop a practical pre-eastward flight treatment to advance circadian rhythms as much as possible but not misalign them with sleep. Design—One group had their sleep schedule advanced by 1 hour per day and another by 2 hours per day. Setting—Baseline at home, treatment in lab. Participants—Young healthy adults (11 men, 15 women) between the ages of 22 and 36 years. Interventions—Three days of a gradually advancing sleep schedule (1 or 2 hours per day) plus intermittent morning bright light (one-half hour ~5000 lux, one-half hour of < 60 lux) for 3.5 hours. Measurements and Results—The dim light melatonin onset was assessed before and after the 3-day treatment. Subjects completed daily sleep logs and symptom questionnaires and wore wrist activity monitors. The dim light melatonin onset advanced more in the 2-hours-per-day group than in the 1-hour-perday group (median phase advances of 1.9 and 1.4 hours), but the difference between the means (1.8 and 1.5 hours) was not statistically significant. By the third treatment day, circadian rhythms were misaligned relative to the sleep schedule, and subjects had difficulty falling asleep in the 2-hoursper-day group, but this was not the case in the 1-hour-per-day group. Nevertheless, the 2-hours-perday group did slightly better on the symptom questionnaires. In general, sleep disturbance and other side effects were small. Conclusions—A gradually advancing sleep schedule with intermittent morning bright light can be used to advance circadian rhythms before eastward flight and, thus, theoretically, prevent or reduce subsequent jet lag. Given the morning light treatment used here, advancing the sleep schedule 2 hours per day is not better than advancing it 1 hour per day because it was too fast for the advance in circadian rhythms. A diagram is provided to help the traveler plan a preflight schedule.

Advancing Circadian Rhythms Before Eastward Flight: A Strategy to Prevent or Reduce Jet Lag

To develop a practical pre-eastward flight treatment to advance circadian rhythms as much as possible but not misalign them with sleep. One group had their sleep schedule advanced by 1 hour per day and another by 2 hours per day. Baseline at home, treatment in lab. Young healthy adults (11 men, 15 women) between the ages of 22 and 36 years. Three days of a gradually advancing sleep schedule (1 or 2 hours per day) plus intermittent morning bright light (one-half hour approximately 5000 lux, one-half hour of <60 lux) for 3.5 hours. The dim light melatonin onset was assessed before and after the 3-day treatment. Subjects completed daily sleep logs and symptom questionnaires and wore wrist activity monitors. The dim light melatonin onset advanced more in the 2-hours-per-day group than in the 1-hour-per-day group (median phase advances of 1.9 and 1.4 hours), but the difference between the means (1.8 and 1.5 hours) was not statistically significant. By the third treatment day, circadian rhythms were misaligned relative to the sleep schedule, and subjects had difficulty falling asleep in the 2-hours-per-day group, but this was not the case in the 1-hour-per-day group. Nevertheless, the 2-hours-per-day group did slightly better on the symptom questionnaires. In general, sleep disturbance and other side effects were small. A gradually advancing sleep schedule with intermittent morning bright light can be used to advance circadian rhythms before eastward flight and, thus, theoretically, prevent or reduce subsequent jet lag. Given the morning light treatment used here, advancing the sleep schedule 2 hours per day is not better than advancing it 1 hour per day because it was too fast for the advance in circadian rhythms. A diagram is provided to help the traveler plan a preflight schedule.

Twenty minutes versus forty-five minutes morning bright light treatment on sleep onset insomnia in elderly subjects

Objective To compare the efficacy of 20 min versus 45 min light exposure for relieving psychophysiological insomnia in the elderly. Methods Prospective recruitment of subjects 60 years and older with psychophysiological insomnia. Random distribution to 20 or 45 min of daily exposure to 10,000 lux for 60 days. Sleep latency, total sleep time, fatigue and activity were measured at baseline and 3 and 6 months posttreatment. Blind analysis of data and comparison were performed using repeated-measure analysis of variance, independent samples t test and Wilcoxon rank signed test. Results At 3 months, improvement was significantly higher in the 45-min versus 20-min condition. At 6 months, variables returned toward baseline in the 20-min but not in the 45-min condition. Conclusions Twenty minutes of bright light treatment leads to a lesser treatment response than 45 min at 3-month follow-up and to a return toward baseline at 6-month follow-up that was not seen with a 45-min exposure.

Effect of Light on Agitation in Institutionalized Patients With Severe Alzheimer Disease

<h3>OBJECTIVE</h3> Preliminary data suggest that morning bright light might improve symptoms of agitation, a serious problem in patients with dementia. The authors expand on an earlier pilot study by evaluating the effect of bright light therapy on agitated behavior in a large sample of patients with severe dementia. <h3>METHODS</h3> Ninety-two patients were randomly assigned to morning bright light, morning dim red light, or evening bright light. Agitation was rated by research staff who observed the patients every 15 minutes throughout the treatment period and by caregivers at one time-point before and one time-point after treatment. <h3>RESULTS</h3> Morning bright light delayed the acrophase of the agitation rhythm by over 1.5 hours. Bright light was associated with improved caregivers' ratings but had little effect on observational ratings of agitation. <h3>CONCLUSION</h3> Although the result that light shifted the peak of the agitated behavior might be generalizable to patients with milder forms of AD, the fact that agitation was not ameliorated might not be. Because the suprachiasmatic nucleus (SCN) of patients with severe AD is likely to be more degenerated, and the circadian activity rhythms deteriorate as the disease progresses, it is still possible that patients with more intact SCNs, that is, patients with mild or moderate AD, might benefit from light treatment even more than those with severe AD.

Effect of Light on Agitation in Institutionalized Patients With Severe Alzheimer Disease

Preliminary data suggest that morning bright light might improve symptoms of agitation, a serious problem in patients with dementia. The authors expand on an earlier pilot study by evaluating the effect of bright light therapy on agitated behavior in a large sample of patients with severe dementia. Ninety-two patients were randomly assigned to morning bright light, morning dim red light, or evening bright light. Agitation was rated by research staff who observed the patients every 15 minutes throughout the treatment period and by caregivers at one time-point before and one time-point after treatment. Morning bright light delayed the acrophase of the agitation rhythm by over 1.5 hours. Bright light was associated with improved caregivers' ratings but had little effect on observational ratings of agitation. Although the result that light shifted the peak of the agitated behavior might be generalizable to patients with milder forms of AD, the fact that agitation was not ameliorated might not be. Because the suprachiasmatic nucleus (SCN) of patients with severe AD is likely to be more degenerated, and the circadian activity rhythms deteriorate as the disease progresses, it is still possible that patients with more intact SCNs, that is, patients with mild or moderate AD, might benefit from light treatment even more than those with severe AD.

Bright-light exposure combined with physical exercise elevates mood

Background: Physical exercise alleviates depressive symptoms, as does exposure to bright light, especially in those with seasonal variation. Our objective was to compare the effect of exercise alone or combined with morning bright light on mood and the health-related quality of life in healthy subjects. Methods: Study subjects were working-age adults, randomized in two groups ( n=80): exercise in bright light (group A), or exercise in normal indoor illumination (group B). Intervention lasted for 8 weeks and questionnaire data on mood and the health-related quality of life were collected at study entry, and at weeks 4 and 8. Results: Physical exercise both in normal indoor illumination and in bright light was effective at alleviating depressive symptoms. The exercise was significantly more effective at alleviating so-called atypical depressive symptoms when combined with bright-light exposure. Limitations: There was no active placebo condition, but a comparative, randomized trial was executed. Conclusions: Physical exercise in bright light had a positive effect on mood and health-related quality of life in a sample of healthy, working-age people. Further research is needed to explore the mechanisms of the apparent additive effect of exercise and light.

Bright Light Treatment Decreases Depression in Institutionalized Older Adults: A Placebo-Controlled Crossover Study

An important parallel exists between patients with seasonal affective disorder and institutionalized older adults. Many older patients, as a result of global physical decline and immobility, are confined to their rooms, experiencing little natural sunlight. Thus, institutionalized older adults are at risk for chronic light deprivation. Testing the hypothesis that chronic light deprivation might be responsible, at least in part, for some depression among institutionalized older adults, the aim of this study was to investigate the efficacy of morning bright light treatment on depression among older adults residing in a long-term care facility. In a placebo controlled, crossover design, participants (N = 10, six women and four men; M age = 83.8) received each of the following: (i) 1 week (5 days) of 10,000 lux (therapeutic dose); (ii) 1 week (5 days) of 300 lux (placebo); or 1 week of no treatment (control). Each week of light treatment was 5 consecutive days, 30 minutes daily, with a wash-out period consisting of 1 week between conditions. Geriatric Depression Scale (GDS) scores at baseline during all treatment conditions were positively correlated (r = .81, p < .01) with months of institutionalization, where participants with higher GDS scores experienced more time institutionalized. Scores on the GDS remained unchanged during the placebo and control conditions, but depression scores decreased significantly during the 10,000 lux treatment (pretest GDS M = 15 vs posttest GDS M = 11, p < .01). After the 10,000 lux treatment, 50% of the participants no longer scored in the depressed range. Improvement during the 10,000 lux condition was positively correlated (r = .62, p < .05) to baseline GDS scores, where participants with higher GDS scores experienced greater improvement following the 10,000 lux treatment. The results of the present study suggest that bright light treatment may be effective among institutionalized older adults, providing nonpharmacological intervention in the treatment of depression. Furthermore, the length of institutionalization may play an important role in determining the efficacy of bright light treatment for older adults in the nursing-home setting.

Effect of short duration morning bright light in elderly men: sleep structure.

Sleep structure was measured in five healthy elderly men in their homes. The subjects were exposed to bright light (6000 lx) for 30 min in the morning or instructed to sit in front of a desktop lighting device without light. Relative to the control conditions, bright light exposure significantly decreased time in bed and the number of awakenings. Rapid eye movement sleep was significantly fragmented by stage 1 sleep in the control condition compared with the bright light condition. These findings indicate that a short duration of morning bright light changes sleep structure and is effective in maintaining sleep.

Bright light therapy for demented nursing home patients with behavioral disturbance

The objective of this study was to examine the effects of morning bright light on behavioral disturbances in dementia using a repeated measures ABA design. We hypothesized that morning bright light in demented patients reduces the agitation rating and directly observed disruptive behavior, but increases observed positive behavior. The study was done in a special care unit of a long term care facility, with 16 demented residents ages 60 to 89, 13 female and three male. Morning bright light (Day-Light Box 10000, produced by DayLight Technologies, Inc, providing 10,000 lux) was administered Monday to Friday during the treatment week. The Global Deterioration Scale rating at baseline, followed by baseline, treatment and post-treatment ratings in the Cohen-Mansfield Agitation Inventory (CMAI) and Environment-Behavior Interaction Code (EBIC) were used as measurements Compared to baseline, the mean total Cohen-Mansfield score decreased more during the phototherapy week than during the post-treatment week (p &lt; 0.05 on one-tailed paired t-test). Regardless of phototherapy, Cohen-Mansfield scores decreased significantly in summer versus fall-spring (p &lt; .005). Although the direct behavioral measures [EBIC] showed no statistically significant change compared to baseline, there was a pattern of greater mean increase in positive behaviors (p = .08) during phototherapy than in the post-treatment week, and a mean decrease of total disruptive behaviors most pronounced in the post-treatment week (p = .05). Bright light therapy has modest efficacy in reducing agitation, with possible concurrent improvement in positive behaviors. Disruptive behaviors may also become less frequent during phototherapy with evidence of even greater delayed optimal effect. Further research should focus on subgroups of patients demonstrating a particularly robust response, enhance power through a larger sample, provide for longer light exposure, and control for seasonal variables.

Bright morning light reduced depressive symptoms in seasonal affective disorder

Bright morning light reduced depressive symptoms in seasonal affective disorder

Effects of short duration morning bright light in healthy elderly. II: sleep and motor activity.

Subjective sleep feelings and motor activity were measured in seven healthy elderly subjects for 6 days. The subjects were exposed to bright light (6000 lux) for 30 min in the morning or instructed to sit in front of a desktop lighting device without light. The average level of motor activity during the night was significantly decreased in the bright light condition, compared with the controlled condition. However, daytime motor activity did not show significant differences between the two conditions. From these findings, even a short duration of morning bright light is effective in maintaining sleep without changing daytime activity.

Effects of short duration morning bright light in healthy elderly subjects. I: subjective feeling and ophthalmological examinations.

Seven aged subjects aged 61-78 years were exposed to 6000 lx bright light for 30 min during morning hours at their homes for 1 week. Visual analog scale was recorded before bedtime and after rising to assess subjective feelings. Ophthalmological examinations were made before and after light exposure, to exclude pre-existing ocular disorders and to detect ocular damage. Furthermore, ocular fatigue was self-evaluated immediately before and after exposure. Visual analog scale results indicated that alertness reduced significantly before bedtime. Ophthalmological abnormalities were not found after exposure. These findings suggest that short duration morning bright light exposure reduces night-time vigilance.

Randomized, DIM Light Controlled, Crossover test of Morning Bright Light Therapy for Rest-Activity Rhythm Disorders in Patients with Vascular Dementia and Dementia of Alzheimer's type

The authors compared the therapeutic effect of morning bright and dim light exposure on rest-activity (R-A) rhythm disorders in patients with vascular dementia (VD) and patients with dementia of Alzheimer's type (DAT). Participants in this study were 12 patients with VD (M/F = 5/7; average age = 81 years) and 10 patients with DAT (M/F = 4/6; average age = 78 years). They were exposed to 2 weeks of bright light (BL; 5000-8000 lux) and 2 weeks of dim light (DL; 300 lux) in the morning (09:00-11:00) in a randomized crossover design in which the 2-week treatment period took place between pretreatment (1 week) and posttreatment (1 week) periods. Continuous R-A monitoring was performed at 1-minute intervals throughout the study using an actigraph around the nondominant wrist. The BL exposure for 2 weeks induced a significant reduction in both nighttime activity and percentages of nighttime activity to total activity compared with the pretreatment period, as well as compared with the DL condition in the VD group, but not in the DAT group. These findings support the assumption that the therapeutic efficacies of morning BL exposure are prominent in VD patients and are mainly due to its photic effect rather than nonphotic effects such as the intensification of social interaction accompanying light therapy. (Chronobiology International, 15(6), 647-654, 1998)

高照度光照射が健常高齢者に及ぼす影響について

高照度光照射が健常高齢者に及ぼす影響について

Circadian temperature and cortisol rhythms during a constant routine are phase-delayed in hypersomnic winter depression

Circadian temperature, cortisol, and thyroid-stimulating hormone (TSH) rhythms during a constant routine were assessed in 6 female controls and 6 female patients with hypersomnic winter depression (seasonal affective disorder, SAD) before and after morning bright light treatment. After sleep was standardized for 6 days, the subjects were sleep-deprived and at bed rest for 27 hours while rectal temperature, cortisol, and TSH levels were assessed. The minimum of the fitted rectal temperature rhythm was phase-delayed in the SAD group compared to the controls 5:42 AM vs. 3:16 AM (p < .005); with bright light treatment, the minimum advanced from 5:42 AM to 3:36 AM (p = .06). The minimum of the cortisol rhythm was phase-delayed in the SAD group compared to the control group, 12:11 AM vs. 10:03 PM (P < .05); with bright light treatment, the minimum advanced from 12:11 AM to 10:38 PM (P = .06) [corrected]. The acrophase of the TSH rhythm was not significantly phase-delayed in SAD subjects compared to control, though the trend appeared to be toward a phase-delay (p = .07). After bright light therapy, the TSH acrophase was not significantly different in the SAD subjects; the trend was a phase-advance (p = .09). Overall, the data suggest that circadian rhythms are phase-delayed relative to sleep in SAD patients and that morning bright light phase-advances those rhythms.

Sleep propensity and sleep architecture after bright light exposure at three different times of day.

The aim of this work was to study the effects of bright light-induced circadian phase shifts on sleep propensity and sleep architecture while the timing of the sleep/wake cycle is kept constant. Twenty-three normal subjects underwent an 11-day study including: (i) baseline sleep and vigilance evaluation; (ii) baseline evaluation of the circadian temperature rhythm with a 40-h constant routine; (iii) five hours of bright light exposure on each of three days; (iv) post-treatment sleep and vigilance evaluation; (v) post-treatment circadian rhythm evaluation with a second 40-h constant routine. Subjects were divided into three groups: eight subjects were exposed to bright light in the morning ('Morning group'), eight subjects were exposed in the evening ('Evening group'), and seven subjects were exposed in the afternoon ('Afternoon group'). After light exposure, the Morning group showed an advance of 1.23 h in the phase of the temperature rhythm, the Evening group showed a delay of 1.62 h, and the Afternoon group showed a non-significant advance of 0.5 h. In support of expectations, early-night sleep propensity was decreased by evening bright light, was increased in almost all subjects exposed to morning bright light, and was not changed by afternoon bright light exposure. The phase shift created by bright light exposure did not seem to be large enough to have a systematic effect on sleep consolidation or on REM sleep parameters in any of the three groups, suggesting that these variables are less sensitive to alterations in phase of the circadian oscillator than early-night sleep propensity.

Effect of morning bright light on body temperature, plasma cortisol and wrist motility measured during 24 hour of constant conditions

Using 24 h constant conditions, time course of body temperature, plasma cortisol and wrist motility was measured in response to a 3 day morning 2 h bright light pulse. This protocol demonstrated that a 2000 lux illumination was sufficient to elicit a shift of about 2 h of temperature minimum and cortisol peak. In reference session, actimetric recordings showed a circadian time course, closely in relation with core temperature. Bright light pulse resulted in a decrease of amplitude and a disappearance of circadian pattern of actimetry.

Aging young sleep: a test of the phase advance hypothesis of sleep disturbance in the elderly.

With aging, the phase relationship between sleep and body core temperature is altered such that the temperature minimum occurs substantially earlier in the major nocturnal sleep period. The sleep maintenance difficulties that often accompany normal aging are generally assumed to be associated with this age-related change in the phase angle between sleep and temperature. To test this notion, we used timed exposure to bright light to reproduce in healthy young adults a similar phase relationship between temperature and sleep, to determine if such a manipulation would induce the same fragmented nocturnal sleep commonly observed in individuals over 65 years of age. Seven young adults were exposed to morning bright light for 3 consecutive days following a baseline night. Bright light exposure caused a 97 min phase advance of the fitted temperature minimum when compared with baseline. Significant declines in several measures of sleep quality were associated with the phase advance, including wakefulness after initial sleep onset (WASO), sleep efficiency and number of stage changes. Yet, the severity of sleep disturbance exhibited by these subjects did not approach that exhibited by most elderly subjects. The findings suggest that while chronophysiological changes appear to be strongly associated with the tendency to awaken in the early morning, they cannot account entirely for the severity of sleep disturbance frequently observed in older subjects.

Effects of light treatment on circadian rhythmicity in seasonal affective disorder

SummaryTwelve outpatients with seasonal affective disorder were treated by 1-h morning bright light exposure for 5 days. The light treatment intervention produced a significant phase advance of self-rated sleepiness rhythm, a significant decrease of the mean level of subjective sleepiness, and a significant reduction of depression scores. No significant objective circadian rhythm phase shift nor amplitude changes would account for the antidepressant effect.

Early morning bright light phase advances the human circadian pacemaker within one day

One day after a single exposure to bright light from 03.00 to 09.00 h the morning declines in the serum melatonin concentration were phase-advanced in all subjects relative to pre-exposure patterns by 1.2–2.6 h. The evening melatonin rise was phase-advanced in 5 out of 6 subjects by 0.6–2.2 h. The data suggest that an underlying human circadian pacemaker controlling the melatonin rhythm may be phase-advanced within one day; however, the evening melatonin rise and the morning decline do not necessarily phase-shift by the same amount.