Nonphotic entrainment of the human circadian pacemaker

1998 ◽  
Vol 274 (4) ◽  
pp. R991-R996 ◽  
Author(s):  
Elizabeth B. Klerman ◽  
David W. Rimmer ◽  
Derk-Jan Dijk ◽  
Richard E. Kronauer ◽  
Joseph F. Rizzo ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Light Exposure ◽  
Core Body Temperature ◽  
Biological Clock ◽  
Bright Light ◽  
Circadian Pacemaker ◽  
Temperature Rhythms ◽  
Blind Individuals ◽  
Nonphotic Entrainment ◽  
Core Body

In organisms as diverse as single-celled algae and humans, light is the primary stimulus mediating entrainment of the circadian biological clock. Reports that some totally blind individuals appear entrained to the 24-h day have suggested that nonphotic stimuli may also be effective circadian synchronizers in humans, although the nonphotic stimuli are probably comparatively weak synchronizers, because the circadian rhythms of many totally blind individuals “free run” even when they maintain a 24-h activity-rest schedule. To investigate entrainment by nonphotic synchronizers, we studied the endogenous circadian melatonin and core body temperature rhythms of 15 totally blind subjects who lacked conscious light perception and exhibited no suppression of plasma melatonin in response to ocular bright-light exposure. Nine of these fifteen blind individuals were able to maintain synchronization to the 24-h day, albeit often at an atypical phase angle of entrainment. Nonphotic stimuli also synchronized the endogenous circadian rhythms of a totally blind individual to a non-24-h schedule while living in constant near darkness. We conclude that nonphotic stimuli can entrain the human circadian pacemaker in some individuals lacking ocular circadian photoreception.

scholarly journals Efficacy of a single sequence of intermittent bright light pulses for delaying circadian phase in humans

2004 ◽  
Vol 287 (1) ◽  
pp. E174-E181 ◽  
Author(s):  
Claude Gronfier ◽  
Kenneth P. Wright ◽  
Richard E. Kronauer ◽  
Megan E. Jewett ◽  
Charles A. Czeisler
Keyword(s):  
Phase Shift ◽  
Light Exposure ◽  
Core Body Temperature ◽  
Bright Light ◽  
Phase Delay ◽  
Continuous Exposure ◽  
Circadian Pacemaker ◽  
Light Pulses ◽  
Dim Light ◽  
Single Sequence

It has been shown in animal studies that exposure to brief pulses of bright light can phase shift the circadian pacemaker and that the resetting action of light is most efficient during the first minutes of light exposure. In humans, multiple consecutive days of exposure to brief bright light pulses have been shown to phase shift the circadian pacemaker. The aim of the present study was to determine whether a single sequence of brief bright light pulses administered during the early biological night would phase delay the human circadian pacemaker. Twenty-one healthy young subjects underwent a 6.5-h light exposure session in one of three randomly assigned conditions: 1) continuous bright light of ∼9,500 lux, 2) intermittent bright light (six 15-min bright light pulses of ∼9,500 lux separated by 60 min of very dim light of <1 lux), and 3) continuous very dim light of <1 lux. Twenty subjects were included in the analysis. Core body temperature (CBT) and melatonin were used as phase markers of the circadian pacemaker. Phase delays of CBT and melatonin rhythms in response to intermittent bright light pulses were comparable to those measured after continuous bright light exposure, even though the total exposure to the intermittent bright light represented only 23% of the 6.5-h continuous exposure. These results demonstrate that a single sequence of intermittent bright light pulses can phase delay the human circadian pacemaker and show that intermittent pulses have a greater resetting efficacy on a per minute basis than does continuous exposure.

Repeated exposures to daytime bright light increase nocturnal melatonin rise and maintain circadian phase in young subjects under fixed sleep schedule

2006 ◽  
Vol 291 (6) ◽  
pp. R1799-R1807 ◽  
Author(s):  
Nana N. Takasu ◽  
Satoko Hashimoto ◽  
Yujiro Yamanaka ◽  
Yusuke Tanahashi ◽  
Ayano Yamazaki ◽  
...  
Keyword(s):  
Body Temperature ◽  
Light Exposure ◽  
Core Body Temperature ◽  
Bright Light ◽  
Peak Level ◽  
Light Conditions ◽  
Circadian Phase ◽  
Sleep Schedule ◽  
Dim Light ◽  
Core Body

Effects of two different light intensities during daytime were examined on human circadian rhythms in plasma melatonin, core body temperature, and wrist activity under a fixed sleep schedule. Sleep qualities as indicated by polysomnography and subjective sleepiness were also measured. In the first week, under dim light conditions (∼10 lx), the onset and peak of nocturnal melatonin rise were significantly delayed, whereas the end of melatonin rise was not changed. The peak level of melatonin rise was not affected. As a result, the width of nocturnal melatonin rise was significantly shortened. In the second week, under bright light conditions (∼5,000 lx), the phases of nocturnal melatonin rise were not changed further, but the peak level was significantly increased. Core body temperature at the initial sleep phase was progressively elevated during the course of dim light exposure and reached the maximum level at the first night of bright light conditions. Subjective sleepiness gradually declined in the course of dim light exposure and reached the minimum level at the first day of bright light. These findings indicate that repeated exposures to daytime bright light are effective in controlling the circadian phase and increasing the peak level of nocturnal melatonin rise in plasma and suggest a close correlation between phase-delay shifts of the onset of nocturnal melatonin rise or body temperature rhythm and daytime sleepiness.

scholarly journals Time-of-day-dependent effects of bright light exposure on human psychophysiology: comparison of daytime and nighttime exposure

2006 ◽  
Vol 290 (5) ◽  
pp. R1413-R1420 ◽  
Author(s):  
Melanie Rüger ◽  
Marijke C. M. Gordijn ◽  
Domien G. M. Beersma ◽  
Bonnie de Vries ◽  
Serge Daan
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Light Exposure ◽  
Core Body Temperature ◽  
Bright Light ◽  
Time Of Day ◽  
Wide Field ◽  
Young Males ◽  
Core Body ◽  
Bright Light Exposure

Bright light can influence human psychophysiology instantaneously by inducing endocrine (suppression of melatonin, increasing cortisol levels), other physiological changes (enhancement of core body temperature), and psychological changes (reduction of sleepiness, increase of alertness). Its broad range of action is reflected in the wide field of applications, ranging from optimizing a work environment to treating depressed patients. For optimally applying bright light and understanding its mechanism, it is crucial to know whether its effects depend on the time of day. In this paper, we report the effects of bright light given at two different times of day on psychological and physiological parameters. Twenty-four subjects participated in two experiments ( n = 12 each). All subjects were nonsmoking, healthy young males (18–30 yr). In both experiments, subjects were exposed to either bright light (5,000 lux) or dim light <10 lux (control condition) either between 12:00 P.M. and 4:00 P.M. ( experiment A) or between midnight and 4:00 A.M. ( experiment B). Hourly measurements included salivary cortisol concentrations, electrocardiogram, sleepiness (Karolinska Sleepiness Scale), fatigue, and energy ratings (Visual Analog Scale). Core body temperature was measured continuously throughout the experiments. Bright light had a time-dependent effect on heart rate and core body temperature; i.e., bright light exposure at night, but not in daytime, increased heart rate and enhanced core body temperature. It had no significant effect at all on cortisol. The effect of bright light on the psychological variables was time independent, since nighttime and daytime bright light reduced sleepiness and fatigue significantly and similarly.

Ambulatory Estimation of Circadian Rhythms Shows Core Body Temperature Phase Precedes Slow Wave Sleep Phase in the Normal Elderly

2020 ◽  
Vol 87 (9) ◽  
pp. S251
Author(s):  
Esther Blessing ◽  
Ankit Paresh ◽  
Arleener Turner ◽  
Andrew Varga ◽  
David Rapoport ◽  
...  
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Slow Wave ◽  
Slow Wave Sleep ◽  
Core Body Temperature ◽  
Temperature Phase ◽  
Sleep Phase ◽  
Core Body

scholarly journals 0169 Misaligned Core Body Temperature Rhythms Impact Cognitive Performance of Hospital Shift Work Nurses

SLEEP ◽  
2019 ◽  
Vol 42 (Supplement_1) ◽  
pp. A69-A70
Author(s):  
Karen L Gamble ◽  
Hylton E Molzof ◽  
Aoyjai L Prapanjaroensin ◽  
Vivek H Patel ◽  
Mugdha V Mokashi ◽  
...  
Keyword(s):  
Body Temperature ◽  
Cognitive Performance ◽  
Shift Work ◽  
Core Body Temperature ◽  
Temperature Rhythms ◽  
Core Body

scholarly journals Misaligned core body temperature rhythms impact cognitive performance of hospital shift work nurses

2019 ◽  
Vol 160 ◽  
pp. 151-159 ◽  
Author(s):  
Hylton E. Molzof ◽  
Aoyjai Prapanjaroensin ◽  
Vivek H. Patel ◽  
Mugdha V. Mokashi ◽  
Karen L. Gamble ◽  
...  
Keyword(s):  
Body Temperature ◽  
Cognitive Performance ◽  
Shift Work ◽  
Core Body Temperature ◽  
Temperature Rhythms ◽  
Core Body

Contemporaneous melatonin administration modifies the circadian response to nocturnal bright light stimuli

1997 ◽  
Vol 272 (2) ◽  
pp. R482-R486 ◽  
Author(s):  
A. Cagnacci ◽  
R. Soldani ◽  
S. S. Yen
Keyword(s):  
Light Exposure ◽  
Light Stimulus ◽  
Core Body Temperature ◽  
Bright Light ◽  
Phase Shifts ◽  
Double Blind ◽  
Circadian Phase ◽  
Melatonin Administration ◽  
Baseline Evaluation ◽  
Light Stimuli

We investigated whether the contemporaneous administration of melatonin can modify circadian phase shifts induced by bright light stimuli. After a baseline evaluation, 10 women were exposed for three consecutive nights to a 4-h bright light stimulus (>3,000 lx) initiated at the time of the estimated core body temperature (BT(c)) nadir. Along with light, each woman orally received, randomly and in a double-blind fashion, placebo (n = 5) or melatonin (n = 5; 1 mg 30 min before and 0.75 mg 120 min after the start of light exposure). Daily rhythms were reevaluated at the end of treatment. Bright light phase advanced, by about 90-120 min, BT(c) (P < 0.01), cortisol (P < 0.05), and melatonin (P < 0.01) rhythms. Contemporaneous administration of melatonin antagonized the phase advances of the cortisol and BT(c) rhythms, as well as the melatonin peak and melatonin offset. The phase advance of the melatonin onset was instead enhanced (P < 0.05). Contemporaneous melatonin administration modifies the capability of light to induce circadian phase shifts.

Twenty-four-hour melatonin and core body temperature rhythms: their adaptation in night workers

1997 ◽  
Vol 272 (3) ◽  
pp. R948-R954 ◽  
Author(s):  
L. Weibel ◽  
K. Spiegel ◽  
C. Gronfier ◽  
M. Follenius ◽  
G. Brandenberger
Keyword(s):  
Core Body Temperature ◽  
Sleep Onset ◽  
Great Variability ◽  
Large Decrease ◽  
Night Sleep ◽  
Sleep Period ◽  
Biphasic Pattern ◽  
Active Schedule ◽  
Temperature Rhythms ◽  
Core Body

To determine whether the melatonin (MT) rhythm is adapted to a permanent nocturnal schedule, 11 night workers were studied during their usual 24-h cycle, and 8 day-active subjects during two 24-h cycles, once with night sleep and once after an acute shift of their sleep period to daytime. Rectal temperature (Tre) was continuously recorded. In day-active subjects, the MT rhythm was not affected by the acute shift in the sleep period, whereas the Tre rhythm was split in a biphasic pattern with the circadian descending phase during the night of sleep deprivation and a second descending trend during day sleep. Night workers showed a great variability in their MT profiles, with the onset of the MT release varying between 2145 and 0505. In contrast, the Tre rhythm was homogeneously entrained to their usual sleep-wake cycle, with the onset of the descending trend initiated before sleep onset so that the large decrease was found, in some subjects, to be uncoupled with their MT increase. The night-active schedule did not induce any amplitude modification of the Tre and the rhythms compared with day-active subjects sleeping at night. No relationship between work-dependent factors and the extent of the MT shift could be found. These results show the great variability in the timing of MT secretion among night workers, in contrast to the homogeneity of their Tre rhythm. The exact mechanisms by which night workers adapt their circadian systems have not yet been identified.

Sign in / Sign up

Export Citation Format

Share Document