Assessing sleep,travelling habits and jet lag in kite surfers according to competition level

This study evaluated sleep duration, travelling habits and jet lag effects in kite surfers according to their competition level. Ninety-four male kite surfers (34.3 ± 8.8 years) were evaluated through an online questionnaire in order to collect information on training volume, clinical history, anthropometric profile, sleep habits, fluid and fruit intake and jet lag effects on athletic performance. Mean sleep duration was 07 h 19 min ± 01 h 12 min on weekdays with 82.3% sleeping less than 8 h/night. Sleep duration was less on weekdays (p = 0.002) and weekends (p = 0.011) in kite surfers‘ squad members (SM) compared to no squad members (NoSM). Greater jet lag symptoms were reported following west-to-east flights. Kite surfers with SM arrived earlier at the competition destination (p = 0.019), were more likely to implement strategies to minimize travel effects (p = 0.003), but reported more symptoms of jet lag than did NoSM (p = 0.041). Travel effects were positively correlated with the distance travelled and negatively correlated with sleep duration on weekdays and water intake during travel to an international kite surfing competition. Jet lag negatively influenced kite surfers’ athletic performance with greater symptoms following west-to-east travel in both SM and NoSM.     

Advancing Schedules and Constant Light Produce Faster Resynchronization of Circadian Rhythms

House sparrows, Passer domesticus, were subjected to rotated light-dark (LD) cycles that consisted of repeated 8-hr advances or delays of 5 days of LD 8:16, with intervening 40-80 hr of constant dark or light. Sparrows reset the fastest (by the second cycle) when they were advanced with intervening constant light (LL). They reset the slowest (taking six cycles) when they were delayed with intervening constant dark (DD).     

昼夜节律钟调控代谢的研究进展

生理和行为的昼夜节律性调控对健康生活是必需的。越来越多的流行病学和遗传学证据显示昼夜节律的破坏与代谢紊乱性疾病相关联。在分子水平上,昼夜节律受到时钟蛋白组成的转录一翻译负反馈环的调控。时钟蛋白通过以下两种途径调节代谢：首先,时钟蛋白作为转录因子直接调节一些代谢关键步骤的限速酶和代谢相关核受体的表达,其次作为代谢相关核受体的辅调节因子来激活或抑制其转录活性。虽然时钟蛋白对代谢途径的调节导致代谢物水平呈昼夜节律振荡,但是产生的代谢物反过来又可以影响昼夜节律钟基因的表达,进而影响昼夜节律钟。深入研究昼夜节律钟与代谢的交互调节可能为治疗某些代谢紊乱性疾病提供新的治疗方案。     

Circadian rhythm disruption: health consequences

Circadian rhythms control many facets of biology and their disruption can be associated with severe pathological conditions. In healthy individuals, disturbances to the sleep-wake cycle can be the root cause of many problems. In the present review, we explore the major factors contributing to circadian rhythm disruption, including sleep disorders, jet lag, and shift work. The consequences of these disruptions on central and peripheral clocks and the important areas of the body controlled by them involve immune function and metabolism, as well as alterations in cognitive abilities, thereby impairing social and occupational behavior. Further work exploring clock genes, light exposure, and cellular changes will be critical for identifying how these factors interact to affect health and behavior.     

Circadian rhythm of activity and sleep‐wakefulness in elderly institutionalized persons

Abstract

The circadian rhythms of blood pressure (BP) and heart rate (HR) were documented in 30 patients for a 24‐hour period before and during the 24 hours that included unilateral surgery for senile cataract or retinal detachment. The patients were premedicated with diazepam. Anaesthesia was induced at a fixed time (09.00) in all patients with thiopentone, and muscle relaxation was with pancuronium. Maintenance was with enflurane in 15 patients and with fentanyl and droperidol in the rest. Though the intraoperative changes in haemodynamic parameters were dissimilar with the two types of maintenance agents, but both types had a similar effect on the circadian rhythms of blood pressure and heart rate. Whereas preoperatively the BP and HR circadian rhythms were nearly in phase, with their peaks in the late morning to early afternoon, the postoperative rhythms underwent a dissociation to a phase shift in the BP 24‐h pattern. The phase effect may be hypothetically attributed to direct pharmacological actions or to masking effects.     

Biological timing in plants

Plants present unique advantages for the study of circadian rhythms. One is the variety of physiological processes that exhibit circadian rhythmicity. The use of novel luminescent reporters of gene expression and of calcium levels recently provided the first clues as to how the clock orchestrates many different activities in parallel. Signaling cascades for the transduction of light signals are the subject of intensive studies, making plants an unparalleled system for the dissection of phototransduction pathways for the entrainment of the clock to daily light–dark cycles. Finally, mutants with aberrant circadian rhythms have been isolated in the small weedArabidopsis, that may lead to the identification of molecular cogs of the circadian oscillator in plants.     

植物生物节律性研究进展

植物的生物节律是植物在亿万年适应环境的过程中经自然选择被保存下来的一种生物内在的、复杂而精细的生理调节系统,是目前植物学领域的一个新的研究热点。就植物近日节律、近年节律等生物节律当前研究成果进行了综述及展望。     

Influence of environmental factors on the wandering phase and pupariation in stable fly, Stomoxys calcitrans, larvae

Abstract. Components of the wandering phase of mature stable fly ( Stomoxys calcitrans L. (Diptera: Muscidae)) larvae were examined. The mean length of the wandering phase was estimated to be 10.6 ± 3.5 h. In a factorial experiment in which wandering larvae were allowed to pupate in media with three levels each of moisture, temperature and light, the mean time to 50% pupariation was delayed and the rate of pupariation was lowest at high moisture levels, but this latter effect was seen only at the moderate light level. Pupae in media with higher moisture contents had significantly higher fresh weights. However, none of the three factors affected dry weight of pupae. A significant interaction was observed between the effects of moisture and temperature on survival; only at highest moisture content and at the highest temperature did a significant decrease in survival occur. In a separate experiment, density was found to have no effect on mean time to 50% pupariation or the rate of pupariation. Puparium formation appeared to be random under a LD 169 h photocycle, showing no apparent circadian rhythm.     

Temporal Organization in Locomotor Activity of the Hypogean Loach, Nemacheilus Evezardi, and its Epigean Ancestor

Locomotor activity rhythm in the hypogean population of Nemacheilus evezardi was recorded first under light-to-dark (LD) 12 : 12 h cycle and then DD. The results were compared with that of its epigean counterpart held under comparable regimes. In LD 12 : 12, while hypogean loach exhibited a distinct bimodality in its locomotor activity rhythm, it was altogether absent in the case of epigean population. In hypogean loach, dark-to-light transition peak in LD was observed to free-run under DD. The same was not discernible in case of epigean loach. The locomotor activity rhythm in epigean fish was noticed to free-run in DD either from the dawn peak or dusk peak in LD. It is hypothesized that the hypogean fish still possesses a functional oscillator underlying its overt circadian rhythm in locomotor activity. The ecophysiological significance of these findings is yet to be fully understood.     

Bedtime misalignment and progression of breast cancer

Disruption of circadian rhythms, which frequently occurs during night shift work, may be associated with cancer progression. The effect of chronotype (preference for behaviors such as sleep, work, or exercise to occur at particular times of day, with an associated difference in circadian physiology) and alignment of bedtime (preferred vs. habitual), however, have not yet been studied in the context of cancer progression in women with breast cancer. Chronotype and alignment of actual bedtime with preferred chronotype were examined using the Morningness–Eveningness Scale (MEQ) and sleep-wake log among 85 women with metastatic breast cancer. Their association with disease-free interval (DFI) was retrospectively examined using the Cox proportional hazards model. Median DFI was 81.9 months for women with aligned bedtimes (“going to bed at preferred bedtime”) (n?=?72), and 46.9 months for women with misaligned bedtimes (“going to bed later or earlier than the preferred bedtime”) (n?=?13) (log rank p?=?0.001). In a multivariate Cox proportional hazard model, after controlling for other significant predictors of DFI, including chronotype (morning type/longer DFI; HR?=?0.539, 95% CI?=?0.320–0.906, p?=?0.021), estrogen receptor (ER) status at initial diagnosis (negative/shorter DFI; HR?=?2.169, 95% CI?=?1.124–4.187, p?=?0.028) and level of natural-killer cell count (lower levels/shorter DFI; HR?=?1.641, 95% CI?=?1.000–2.695, p?=?0.050), misaligned bedtimes was associated with shorter DFI, compared to aligned bedtimes (HR?=?3.180, 95% CI?=?1.327–7.616, p?=?0.018). Our data indicate that a misalignment of bedtime on a daily basis, an indication of circadian disruption, is associated with more rapid breast cancer progression as measured by DFI. Considering the limitations of small sample size and study design, a prospective study with a larger sample is necessary to explore their causal relationship and underlying mechanisms.