Peak Of Body Temperature Research Articles

1220. Disruption of the Body Temperature Circadian Rhythm in Hospitalized Patients

BackgroundThe circadian rhythm is believed to offer survival advantage with dysregulation being linked to immune response deficiencies and metabolic derangements. Diurnal temperature variation exists in humans, yet its preservation during illness is not well understood. Herein we present an analysis of diurnal body temperatures among hospitalized patients, with a focus on infectious versus non-infectious diagnoses.MethodsTemperatures measured within 1/2 hour of 8am, 12pm, 4pm, 8pm, 12 am, and 4am from 16,245 hospitalized patients were analyzed using descriptive statistics and t-tests.ResultsAlthough we found a diurnal pattern when analyzing the ensemble of temperatures from all patients (Figure 1), stratified by measurement site (oral, axillary, temporal, and tympanic), the through-to-peak difference was only 0.2F (0.1C), while previously reported diurnal difference in healthy volunteers was 1.9 °F (1.06 °C). Data from the core body temperature sites monotherm and rectal did not show any diurnal pattern. The peaks in body temperature occurred at 8 pm for all patients, regardless of age, which is similar to healthy people. However, the minimum body temperature was shifted to later times compared with healthy people (6am or 2 hours before rising in health) – for young patients (age 20-30 years, N=1285) the through was at 8am and for elderly patients (age 70-80 years, N=1736), it was at 12pm (Figure 2). Analysis of body temperature of individual patients showed that less than 20% of patients exhibited diurnal variation and among those showing variation, the trend was present only on the minority of hospitalization days (Table 1). Interestingly, the presence or absence of an infectious process did not influence the proportion of patients showing diurnal variation.Figure 1 Figure 2 Table 1 ConclusionHospitalization is associated with disruption in the circadian rhythm as reflected by patients’ body temperature, with shifting of the diurnal variation curve and blunting of the temperature range both in the ensemble and on the individual level. The trend is not influenced by having an infection. However, since core body temperatures tend to be the measurement site of choice in the ICU setting, we suspect that further obliteration of the diurnal rhythm occurs with more severe disease.Disclosures All Authors: No reported disclosures

The Athlete Specific Chronotype Index (ACTi)

The circadian variation of athletic performance has been observed to coincide with daily peaks in body temperature. Chronotypes (CT) take into account inter-individual variations in circadian rhythms, yet there is discord regarding the relationship between CT and athletic performance. This may be due to the most common chronotyping method, the Morningness-Eveningness Questionnaire (MEQ), lacking validity for athletic populations. PURPOSE: The purpose of this study was to develop and validate an athlete specific CT index (ACTi). METHODS: 297 athletes completed a CT questionnaire in MEQ (19) and newly-developed questions (15). Principle component analysis (PCA) was used to identify common themes and reduce the final number of questions. 10 respondents from each CT category, as determined by the MEQ, then participated in a 24-hour laboratory study. Participants abided by their typical sleep/wake cycle, provided hourly saliva samples (for dim light melatonin onset (DLMO) analysis) whilst awake and hourly core body temperature (CBT) readings (ingestible thermistor) for the 24-hours. Stepwise multiple linear regression analysis to predict DLMO onset and CBT was used to further refine the ACTi. RESULTS: PCA of the extended ACTi responses were performed, identifying 7 themes. Multiple regression identified 11 questions that explained DLMO (r2=0.81), forming the final ACTi. DLMO CT differences were observed between MEQ morning-type (MT) and intermittent-type (IT) (64±61.6 min, p=0.02); and MT and evening-type (ET) (114±71.2min, p=0.002). No CT differences were observed in CBT for MEQ or ACTi. Cohen’s Kappa revealed moderate CT classification changes between MEQ and ACTi (0.62). CONCLUSION: The ACTi is an 11-point index that enhances CT determination of athletes versus MEQ, based on the criterion measure DLMO. The ACTi may be used in team-sports to examine the impact of CT upon performance, monitoring of training responsiveness and athlete wellbeing.

Relationship between Early Peak Temperature and Neutropenia Duration in Acute Leukemia Patients after Chemotherapy and Its Mechanism

To investigate the relationship between early peak body temperature and neutropenia duration and its potential mechanism. A total of 111 patients with CR1 phase acute leukemia (AL) with neutropenia infection were enrolled in this study. The relationship between early peak body temperature and neutropenia duration was analyzed retrospectively, and the IL-6 serum level in patients with different peak of body temperature was detected, and the single cell culture system in vitro was established, the incorparation rate of EdU in vivo was detected, and the effect of IL-6 on mouse hematopoietic stem cells /progenitor cells was analyzed. Out of 111 patients with nentropenia, the body temperature <38 °C and the neutropenia duration 9.5±3.69 d were observed in 44 patients, while the body temperature >38 °C and neutropenia duration 7.33±4.20 d were observed in 69 patients, the differences between 2 groups was statistically signficant (P<0.05). The EdU test showed that the number of EdU+ hematopoietic stem cells and progenitor cells increased. The IL-6 level was different in patients with different peaks of initial bady temperature (P<0.05). The results of amimal experiment showed that the IL-6 could promote the proliferation of hematopoietic stem cells/ progenitor cells in vitro and in vivo. For patients with neutropenic infection when initial body temperature peak is <38 °C, the probability of neutropenia duration prolonging after chamotherapy increases, which may relate with promotive effect of pro-inflammatory cytokins on prliferation of hematopoietic stem cells/progenitor cells.

Effect of intermittent fasting on circadian rhythms in mice depends on feeding time

Calorie restriction (CR) resets circadian rhythms and extends life span. Intermittent fasting (IF) also extends life span, but its affect on circadian rhythms has not been studied. To study the effect of IF alongside CR, we imposed IF in FVB/N mice or IF combined with CR using the transgenic FVB/N alphaMUPA mice that, when fed ad libitum, exhibit spontaneously reduced eating and extended life span. Our results show that when food was introduced during the light period, body temperature peak was not disrupted. In contrast, IF caused almost arrhythmicity in clock gene expression in the liver and advanced mPer2 and mClock expression. However, IF restored the amplitudes of clock gene expression under disruptive light condition regardless whether the animals were calorically restricted or not. Unlike daytime feeding, nighttime feeding yielded rhythms similar to those generated during ad libitum feeding. Taken together, our results show that IF can affect circadian rhythms differently depending on the timing of food availability, and suggest that this regimen induces a metabolic state that affects the suprachiasmatic nuclei (SCN) clock.

Radiotelemetric measurement of body temperature in feedlot steers during winter.

Little is known concerning body temperature regulation in cattle under conditions of low ambient temperature. To investigate the influence of cold on body temperature regulation, core body temperatures of feedlot steers (crossbred Bos taurus) were monitored for two winters in Nebraska, from late December to mid-March in yr 1 and from late December through June in yr 2. In yr 1, radiotransmitters to monitor temperature were implanted in the peritoneum of five steers (360 kg); in yr 2, four steers (320 kg) were used. Body temperatures and ambient temperatures were recorded at 3-min intervals and were mathematically filtered to produce 120 readings/d. For yr 1 and 2, daily maximum (40.09 and 39.66 degrees C), minimum (38.78 and 38.64 degrees C), and average (39.29 and 39.06 degrees C) body temperatures were not affected by ambient temperatures. Body temperatures exhibited circadian rhythms with the minima at approximately 0800 and the maxima at approximately 1900. For both years, sharp peaks in body temperature were often seen in the evening and, for yr 2, to a lesser extent in the morning. The occurrence of peaks was normally congruent, within a 1.5-h window, across steers. Congruent peaks in the evening with peak heights of 1.05 and .77 degrees C occurred on 65 and 56% of the days in yr 1 and 2, respectively. Occurrence of congruent peaks was correlated with dusk; peaks followed dusk by 30 to 60 min. Ambient temperature also influenced the occurrence of peaks; few peaks were observed when average daily ambient temperatures were below -7.5 degrees C. The dynamic changes in body temperature throughout the day, including the peaks in body temperature after dusk, strongly suggest that thermoregulatory systems in steers respond not only to current ambient conditions, but also to more integrative measures such as day length and daily heat load.

Radiotelemetry measurement of body temperatures of feedlot steers during summer.

Heat stress is a common problem for cattle. General consequences of heat stress include increased body temperatures and reduced feed intakes. As a measure of heat stress, core body temperatures of unshaded feedlot steers (crossbred Bos taurus) were monitored from mid-June to early November in Nebraska using transmitters implanted in the peritoneum of 10 steers (initially 10 mo of age). Steers were fed at 0630 and 1430 using a finishing diet of 1.52 NEg Mcal/kg with 13% protein and 4% roughage per day and housed in two open lots with stocking densities of 15.2 or 19.3 m2/steer. Core body temperatures, ambient temperature, relative humidity, and wind speed were measured at 3-min intervals and mathematically filtered to produce 120 readings/ d. For 94 usable daily records, body temperature means (39.04 +/- .12 degrees C), maxima (39.89 +/- .21 degrees C at 1836 +/- .73 h), minima (38.33 +/- .29 degrees C at 0823 +/- .38 h), and patterns were similar among steers. As daily maximum ambient temperatures increased, minimum body temperatures decreased slightly (.04 degree C per 5 degrees C; P < .01). After daily maximum ambient temperatures reached a threshold of 25.6 degrees C, daily maximum body temperatures increased linearly with maximum ambient temperatures (.42 degree C per 5 degrees C; P < .01). Sharp peaks in body temperature were often seen in the late evening (approximately 2200) after ambient temperature had decreased to well below maximum values. These evening peaks occurred on an average of 25% of the days, had amplitudes ranging from .7 to 3.5 degrees C relative to mean daily temperatures and lasted for 1.5 h. From a practical standpoint, we suggest that producers monitor meteorological forecast of peak ambient temperatures and make special efforts, such as spraying animals, when exceptionally hot weather is predicted.

Behavioral patterns associated with oviposition in Japanese quail and chickens

Abstract The relation of time of oviposition to transient peaks in body temperature was studied in Coturnix (Japanese quail) under different photoperiods and intensities. Other diurnal patterns such as feeding, drinking and locomotor activity were measured for Coturnix and chickens and related to time of oviposition. Feeding, drinking and locomotor activity in Coturnix are closely related to the light period of the day. Increased periods of feeding and drinking occur shortly after the onset of light and during a period of 3 hours prior to darkness. A significant increase in body temperature in the Coturnix began about 1 hour prior to oviposition, with the peak being reached at time of oviposition. This phenomenon was evident even when the photoperiod was changed from continuous to intermittent light. Both peaks were displaced in time approximately 2 hours each day, i.e., a 26‐hour rhythm. There was a definite decrease in feed and water consumption in laying chickens some 3 hours pre‐oviposition, with the ...