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 ◽  
...  
2007 ◽  
Vol 104 (18) ◽  
pp. 7634-7639 ◽  
Author(s):  
Trinitat Cambras ◽  
John R. Weller ◽  
Montserrat Anglès-Pujoràs ◽  
Michael L. Lee ◽  
Andrea Christopher ◽  
...  

Proper functioning of the human circadian timing system is crucial to physical and mental health. Much of what we know about this system is based on experimental protocols that induce the desynchronization of behavioral and physiological rhythms within individual subjects, but the neural (or extraneural) substrates for such desynchronization are unknown. We have developed an animal model of human internal desynchrony in which rats are exposed to artificially short (22-h) light–dark cycles. Under these conditions, locomotor activity, sleep–wake, and slow-wave sleep (SWS) exhibit two rhythms within individual animals, one entrained to the 22-h light–dark cycle and the other free-running with a period >24 h (τ>24 h). Whereas core body temperature showed two rhythms as well, further analysis indicates this variable oscillates more according to the τ>24 h rhythm than to the 22-h rhythm, and that this oscillation is due to an activity-independent circadian regulation. Paradoxical sleep (PS), on the other hand, shows only one free-running rhythm. Our results show that, similarly to humans, (i) circadian rhythms can be internally dissociated in a controlled and predictable manner in the rat and (ii) the circadian rhythms of sleep–wake and SWS can be desynchronized from the rhythms of PS and core body temperature within individual animals. This model now allows for a deeper understanding of the human timekeeping mechanism, for testing potential therapies for circadian dysrhythmias, and for studying the biology of PS and SWS states in a neurologically intact model.


2019 ◽  
Vol 127 (1) ◽  
pp. 168-177 ◽  
Author(s):  
Sayaka Aritake-Okada ◽  
Kosuke Tanabe ◽  
Yoshiko Mochizuki ◽  
Ryuji Ochiai ◽  
Masanobu Hibi ◽  
...  

The effects of exercise on sleep have been explored from various perspectives, but little is known about how the effects of acute exercise on sleep are produced through physiological functions. We used a protocol of multiple daytime sessions of moderate-intensity aerobic exercise and examined the subsequent effects on sleep structure, core body temperature (CBT), distal-proximal skin temperature gradient (DPG), and subjective parameters. Fourteen healthy men who did not exercise regularly were evaluated under the baseline (no exercise) and exercise conditions on a within-subject crossover basis. Under the exercise condition, each participant performed a 40-min aerobic workout at 40% of maximal oxygen intake, four times between morning and early evening. We observed a 33% increase in slow-wave sleep (SWS; P = 0.005), as well as increases in slow-wave activity (SWA; P = 0.026), the fast-sigma power/SWA ratio ( P = 0.005), and subjective sleep depth and restorativeness the following morning. Moreover, both CBT and the DPG increased during sleep after exercise ( P = 0.021 and P = 0.047, respectively). Regression analysis identified an increased nocturnal DPG during sleep after exercise as a factor in the increase in SWA. The fast-sigma/SWA ratio correlated with CBT. The performance of acute exercise promotes SWS with nocturnal elevation in the DPG. Both CBT and fast-sigma power may play a role in the specific physiological status of the body after exercise.NEW & NOTEWORTHY We used multiple daytime sessions of moderate-intensity aerobic exercise to examine the effects on the sleep structure, core body temperature (CBT), distal-proximal skin temperature gradient (DPG), and subjective parameters. Significant increases in slow-wave activity (SWA), CBT, DPG, fast-sigma power, and subjective parameters were observed during the night and the following morning. Nocturnal DPG is a factor in the increased SWA.


2002 ◽  
Vol 17 (5) ◽  
pp. 447-462 ◽  
Author(s):  
Douglas E. Moul ◽  
Hernando Ombao ◽  
Timothy H. Monk ◽  
Qingxia Chen ◽  
Daniel J. Buysse

2021 ◽  
Vol 12 ◽  
Author(s):  
Stefan Mendt ◽  
Katharina Brauns ◽  
Anika Friedl-Werner ◽  
Daniel L. Belavy ◽  
Mathias Steinach ◽  
...  

Spaceflight can be associated with sleep loss and circadian misalignment as a result of non-24 h light-dark cycles, operational shifts in work/rest cycles, high workload under pressure, and psychological factors. Head-down tilt bed rest (HDBR) is an established model to mimic some of the physiological and psychological adaptions observed in spaceflight. Data on the effects of HDBR on circadian rhythms are scarce. To address this gap, we analyzed the change in the circadian rhythm of core body temperature (CBT) in two 60-day HDBR studies sponsored by the European Space Agency [n = 13 men, age: 31.1 ± 8.2 years (M ± SD)]. CBT was recorded for 36 h using a non-invasive and validated dual-sensor heatflux technology during the 3rd and the 8th week of HDBR. Bed rest induced a significant phase delay from the 3rd to the 8th week of HDBR (16.23 vs. 16.68 h, p = 0.005, g = 0.85) irrespective of the study site (p = 0.416, g = −0.46), corresponding to an average phase delay of about 0.9 min per day of HDBR. In conclusion, long-term bed rest weakens the entrainment of the circadian system to the 24-h day. We attribute this effect to the immobilization and reduced physical activity levels associated with HDBR. Given the critical role of diurnal rhythms for various physiological functions and behavior, our findings highlight the importance of monitoring circadian rhythms in circumstances in which gravity or physical activity levels are altered.


2011 ◽  
Vol 300 (3) ◽  
pp. R519-R530 ◽  
Author(s):  
Jens Hannibal ◽  
Hansen M. Hsiung ◽  
Jan Fahrenkrug

Neurons of the brain's biological clock located in the hypothalamic suprachiasmatic nucleus (SCN) generate circadian rhythms of physiology (core body temperature, hormone secretion, locomotor activity, sleep/wake, and heart rate) with distinct temporal phasing when entrained by the light/dark (LD) cycle. The neuropeptide vasoactive intestinal polypetide (VIP) and its receptor (VPAC2) are highly expressed in the SCN. Recent studies indicate that VIPergic signaling plays an essential role in the maintenance of ongoing circadian rhythmicity by synchronizing SCN cells and by maintaining rhythmicity within individual neurons. To further increase the understanding of the role of VPAC2 signaling in circadian regulation, we implanted telemetric devices and simultaneously measured core body temperature, spontaneous activity, and heart rate in a strain of VPAC2-deficient mice and compared these observations with observations made from mice examined by wheel-running activity. The study demonstrates that VPAC2 signaling is necessary for a functional circadian clock driving locomotor activity, core body temperature, and heart rate rhythmicity, since VPAC2-deficient mice lose the rhythms in all three parameters when placed under constant conditions (of either light or darkness). Furthermore, although 24-h rhythms for three parameters are retained in VPAC2-deficient mice during the LD cycle, the temperature rhythm displays markedly altered time course and profile, rising earlier and peaking ∼4–6 h prior to that of wild-type mice. The use of telemetric devices to measure circadian locomotor activity, temperature, and heart rate, together with the classical determination of circadian rhythms of wheel-running activity, raises questions about how representative wheel-running activity may be of other behavioral parameters, especially when animals have altered circadian phenotype.


2016 ◽  
Vol 34 (5) ◽  
pp. 666-676 ◽  
Author(s):  
Stefan Mendt ◽  
Martina Anna Maggioni ◽  
Michael Nordine ◽  
Mathias Steinach ◽  
Oliver Opatz ◽  
...  

2014 ◽  
Vol 31 (8) ◽  
pp. 917-925 ◽  
Author(s):  
Jeremy C. Borniger ◽  
Santosh K. Maurya ◽  
Muthu Periasamy ◽  
Randy J. Nelson

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