Chronic jet-lag increases mortality in aged mice

Abstract

Despite the fact that trans-meridian travel and shift work are commonplace in our 24/7 society, few controlled studies have addressed the health effects of repeated phase shifts of the biological clock. Shift work [1] and chronic jet-lag [2] reduce mental acuity and increase the risk of a number of medical problems including cancer, digestive diseases including peptic ulcers, and sleep disorders. Some of these problems become more severe with the number of years on the job, the result either of cumulative damage or the increased age of the subjects [3]. In general, morbidity associated with many organic disorders is increased in the aged; however, the role played by age-associated alterations in the circadian clock is poorly understood. In particular the effect of repeated schedule changes is largely unaddressed.

Physiologically Relevant Changes in Serotonin Resolved by Fast Microdialysis

“…51,52 Due to circadian rhythms, time of day is an important consideration when performing research on living subjects. 53 Jurgen Aschoff, one of the founders of chronobiology, introduced the concept of "zeitgeber [time-giver] time" in the 1960s to simplify the reporting of results that were impacted by circadian-linked changes. Using this system, the time at which daylight emerges or the lights turn on in the laboratory is referred to as zeitgeber time zero (ZT0).…”

Night‐time work predisposes to non‐Hodgkin lymphoma

“…26 Moreover, advances in the light-dark transitions hasten the death of aged mice. 27 In humans, such advances can take place after flights crossing time zones or shift work schedules. The precise mechanism of action underlying this hazardous effect is not stressrelated but links more likely to sleep deprivation or disruption of the immune system.…”

Disruption of circadian clocks has ramifications for metabolism, brain, and behavior

“…The ramifications of this desynchronization for mental and physical health are not fully understood, although numerous lines of evidence are emerging that link defects in circadian timing with negative health outcomes (2,3). Animal models have shown that chronic circadian disruption can alter mortality rates in tau mutant hamsters (4) and in aged mice (5). The current obesity epidemic in Western societies has also occurred hand-inhand with a gradual decrease in sleep time and sleep quality (6), and although largely correlative, a potential causal link is plausible.…”