Thermochron iButtons: An Inexpensive Method for Long-Term Recording of Core Body Temperature in Untethered Animals

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.

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Long-term measurement of body temperature in the southern hairy-nosed wombat (Lasiorhinus latifrons)

Australian Mammalogy ◽

10.1071/am15041 ◽

2017 ◽

Vol 39 (1) ◽

pp. 48 ◽

Cited By ~ 1

Author(s):

K. A. Descovich ◽

S. Johnston ◽

A. Lisle ◽

V. Nicolson ◽

T. Janssen ◽

...

Keyword(s):

Body Temperature ◽

Ambient Temperature ◽

Core Body Temperature ◽

Late Winter ◽

Comprehensive Picture ◽

Burrow Use ◽

Core Body ◽

The Relationship ◽

Environmental Temperatures

The southern hairy-nosed wombat (Lasiorhinus latifrons) is a nocturnal, fossorial marsupial that has evolved a range of physiological and behavioural adaptations to its semiarid environment. This study describes long-term core body temperature (Tb) of L. latifrons in a population with opportunities for behavioural thermoregulation through burrow use. Tb was measured hourly in 12 captive L. latifrons using implanted dataloggers over a 9-month period from late winter to late autumn. Data were examined for daily patterns, seasonal changes, sex differences and the relationship with environmental conditions (ambient temperature, den temperature and relative humidity). Tb ranged from 30.9 to 38.8°C, and had a distinct nychthemeral rhythm, with peak temperatures occurring at night in line with nocturnal activity. Females had a higher mean Tb (34.9°C) than males (34.4°C). The relationship between external ambient temperature and body temperature was negative, with body temperature decreasing as ambient temperature increased. This study is an important step towards a comprehensive picture of thermoregulation in L. latifrons, which may become vulnerable in the future if environmental temperatures rise and water availability decreases.

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Body Temperature Is Associated With Cognitive Performance in Older Adults With and Without Mild Cognitive Impairment: A Cross-sectional Analysis

Frontiers in Aging Neuroscience ◽

10.3389/fnagi.2021.585904 ◽

2021 ◽

Vol 13 ◽

Author(s):

Patrick Eggenberger ◽

Michael Bürgisser ◽

René M. Rossi ◽

Simon Annaheim

Keyword(s):

Older Adults ◽

Body Temperature ◽

Skin Temperature ◽

Cognitive Performance ◽

Core Body Temperature ◽

Single Point ◽

Body Temperatures ◽

Core Body ◽

Temperature Amplitude

Wearable devices for remote and continuous health monitoring in older populations frequently include sensors for body temperature measurements (i.e., skin and core body temperatures). Healthy aging is associated with core body temperatures that are in the lower range of age-related normal values (36.3 ± 0.6°C, oral temperature), while patients with Alzheimer’s disease (AD) exhibit core body temperatures above normal values (up to 0.2°C). However, the relation of body temperature measures with neurocognitive health in older adults remains unknown. This study aimed to explore the association of body temperature with cognitive performance in older adults with and without mild cognitive impairment (MCI). Eighty community-dwelling older adults (≥65 years) participated, of which 54 participants were cognitively healthy and 26 participants met the criteria for MCI. Skin temperatures at the rib cage and the scapula were measured in the laboratory (single-point measurement) and neuropsychological tests were conducted to assess general cognitive performance, episodic memory, verbal fluency, executive function, and processing speed. In a subgroup (n = 15, nine healthy, six MCI), skin and core body temperatures were measured continuously during 12 h of habitual daily activities (long-term measurement). Spearman’s partial correlation analyses, controlled for age, revealed that lower median body temperature and higher peak-to-peak body temperature amplitude was associated with better general cognitive performance and with better performance in specific domains of cognition; [e.g., rib median skin temperature (single-point) vs. processing speed: rs = 0.33, p = 0.002; rib median skin temperature (long-term) vs. executive function: rs = 0.56, p = 0.023; and peak-to-peak core body temperature amplitude (long-term) vs. episodic memory: rs = 0.51, p = 0.032]. Additionally, cognitively healthy older adults showed lower median body temperature and higher peak-to-peak body temperature amplitude compared to older adults with MCI (e.g., rib median skin temperature, single-point: p = 0.035, r = 0.20). We conclude that both skin and core body temperature measures are potential early biomarkers of cognitive decline and preclinical symptoms of MCI/AD. It may therefore be promising to integrate body temperature measures into multi-parameter systems for the remote and continuous monitoring of neurocognitive health in older adults.

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Measurement of Core Body Temperature Using Graphene-Inked Infrared Thermopile Sensor

Sensors ◽

10.3390/s18103315 ◽

2018 ◽

Vol 18 (10) ◽

pp. 3315 ◽

Cited By ~ 7

Author(s):

Jorge Chaglla E. ◽

Numan Celik ◽

Wamadeva Balachandran

Keyword(s):

Body Temperature ◽

Computer Aided Design ◽

Core Body Temperature ◽

Total Period ◽

Non Invasive ◽

Invasive Method ◽

Thermopile Sensor ◽

Aided Design ◽

Core Body

Continuous and reliable measurements of core body temperature (CBT) are vital for studies on human thermoregulation. Because tympanic membrane directly reflects the temperature of the carotid artery, it is an accurate and non-invasive method to record CBT. However, commercial tympanic thermometers lack portability and continuous measurements. In this study, graphene inks were utilized to increase the accuracy of the temperature measurements from the ear by coating graphene platelets on the lens of an infrared thermopile sensor. The proposed ear-based device was designed by investigating ear canal geometry and developed with 3D printing technology using the Computer-Aided Design (CAD) Software, SolidWorks 2016. It employs an Arduino Pro Mini and a Bluetooth module. The proposed system runs with a 3.7 V, 850 mAh rechargeable lithium-polymer battery that allows long-term, continuous monitoring. Raw data are continuously and wirelessly plotted on a mobile phone app. The test was performed on 10 subjects under resting and exercising in a total period of 25 min. Achieved results were compared with the commercially available Braun Thermoscan, Original Thermopile, and Cosinuss One ear thermometers. It is also comprehended that such system will be useful in personalized medicine as wearable in-ear device with wireless connectivity.

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Regular exercise counteracts circadian shifts in core body temperature during long-duration bed rest

npj Microgravity ◽

10.1038/s41526-020-00129-1 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Stefan Mendt ◽

Hanns-Christian Gunga ◽

Dieter Felsenberg ◽

Daniel L. Belavy ◽

Mathias Steinach ◽

...

Keyword(s):

Body Temperature ◽

Core Body Temperature ◽

Space Station ◽

Bed Rest ◽

Resistive Exercise ◽

Long Duration ◽

Human Exploration ◽

Core Body

AbstractWith NASA’s plans for the human exploration of Mars, astronauts will be exposed to mission durations much longer than current spaceflight missions on the International Space Station. These mission durations will increase the risk for circadian misalignment. Exercise has gained increasing interest as a non-pharmacological aid to entrain the circadian system. To assess the potential of exercise as a countermeasure to mitigate the risk for circadian disorders during spaceflight, we investigated the effects of long-term head-down tilt bed rest (HDBR) with and without exercise on the circadian rhythm of core body temperature. Core body temperature was recorded for 24 h using a rectal probe in sixteen healthy men (age: 30.5 ± 7.5 years (mean ± SD)) after 7 days and 49 days of HDBR. Five participants underwent HDBR only (CTR), five participants underwent HDBR and performed resistive exercises (RE), and six participants underwent HDBR and performed resistive exercises superimposed with vibrations (RVE). The exercise was scheduled three times per week. CTR showed a phase delay of 0.69 h. In contrast, both exercise groups were characterized by a phase advance (0.45 h for RE and 0.45 h for RVE; p = 0.026 for interaction between time and group). These findings suggest that resistive exercise (with or without vibration) may also serve as a countermeasure during spaceflight to mitigate circadian misalignments. The results could also be important for increasing awareness about the role of circadian disorders in long-term bedridden patients.

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