Bright light effects on body temperature, alertness, EEG and behavior

Shift-Work Disorder and Sleep-Related Environmental Factors in the Manufacturing Industry

“…We hypothesized that the environment (temperature and humidity, brightness, noise, smell) in which one tries to fall asleep may induce SWD, as several reports have associated these factors with sleep [21][22][23][24][25][26][27]. For example, temperatures under 21°C and above 29°C have been associated with arousal during sleep [21].…”

“…For example, temperatures under 21°C and above 29°C have been associated with arousal during sleep [21]. Humidity has been correlated with increased wakefulness and decreased slow-wave sleep and rapid eye movement (REM) sleep [22], and brightness has been reported to cause awakening [23], melatonin inhibition [24], high body temperature [25], and stimulation of the sympathetic nervous system [26]. Noise also reduced slow-wave sleep and REM sleep [27].…”

What Keeps Us Awake?—the Role of Clocks and Hourglasses, Light, and Melatonin

“…In fact, a change in the timing of the external LD cycle leads to a shift in endogenous phase of circadian rhythms (Brainard et al, 1997). Besides these long-term effects on circadian phase, many acute effects of light have been consistently shown for a wide range of physiological processes, such as hormonal secretion, heart rate, sleep propensity, alertness, body temperature, pupillary constriction, and gene expression (Aalto and Hilakivi, 1986;Badia et al, 1991;Berson, 2003;Cajochen et al, 1992Cajochen et al, , 1996Cajochen et al, , 2005Cajochen et al, , 2006Lavoie et al, 2003;Muñoz et al, 2005). Both long-term and acute effects of light are usually referred to as non visual (or non-image forming, NIF) effects, since they drift apart from the classical involvement of rod and cone photopigments in the visual responses to light.…”

Lighting as a Circadian Rhythm-Entraining and Alertness-Enhancing Stimulus in the Submarine Environment

“…Badia et al [41] studied the effects of bright white light on body temperature, alertness, and performance. Subjects were exposed to 90-minute periods of alternating bright (5000 to 10,000 lux) and dim (50 lux) light during daytime and nighttime.…”

“…They found a short-term alerting effect of the light, using recorded electrophysiological brain activity, and also found a reduction in feelings of sleepiness. Building on the evidence that light can have alerting effects at night and on the knowledge that the circadian system is maximally sensitive to short-wavelength (blue light) radiation, Cajochen et al [45] reported results similar to Badia et al [41], but used only 5 lux of blue light for a about 40 minutes, in comparison with the much higher light levels and longer durations of white light used by Badia et al [41].…”