Validation of e-Celsius gastrointestinal telemetry system as measure of core temperature

Effect of aerobic fitness on the validity of the Calera Research™ sensor to estimate core temperature during exercise

The Calera Research™ is a heat flux device advertised to estimate core temperature (Tc) during physical activity and is widely used by athletes in various sport disciplines. The device estimates Tc from skin temperature, heart rate, and heat flux, outcomes that can be affected by aerobic fitness. However, there is a relatively small body of literature exploring its validity and, specifically, how the device bias may be influenced by aerobic fitness. The objective of this study was to assess the validity of the Calera Research™ sensor compared with telemetric ingestible pills for estimating Tc and to determine whether aerobic fitness impacts accuracy. Twenty participants (10 females) performed a cycling-based ramp-incremental exercise test to volitional exhaustion in a temperature controlled environment (22 °C) during which Tc was measured directly from ingested pills (eCelsius performance system) and by the Calera device. Compared to the ingestible telemetric pills, the Calera device exhibited lower Tc values (95%CI[-0.2, -0.3 °C], p < 0.001) with an intraclass correlation of 0.47 and a bias of -0.3 ± 0.2 °C. Participants were divided into two groups (10 participants at each group) based on peak oxygen uptake (V˙ O2peak) (HL: high aerobic; LL: lower aerobic fitness). Throughout ramp-incremental exercise, HL had a lower heart rate (p < 0.001 and η2 = 0.10; 95%CI[0.1, 17.2 bits/min]) and Tc measured by the ingestible pills (p < 0.001 and η2 < 0.01, 95%CI[0.1, 0.3 °C]). However, there were no-between group differences for skin temperature and intraclass correlation values and bias were also similar. In conclusion, the estimation of Tc by Calera Research™ underestimated Tc by approximately 0.3 °C in a moderate thermal environment, but the intensity-dependent profile was similar to that of the ingestible pill method and was unaffected by aerobic fitness differences.

An overview of emerging smart capsules using other-than-light technologies for colonic disease detection

Wireless capsule endoscopy (CE) has revolutionized gastrointestinal diagnostics, offering a non-invasive means to visualize and monitor the GI tract. This review traces the evolution of CE technology. Addressing the limitations of traditional white light (WL) CE, the paper explores non-WL technologies, integrating diverse sensing modalities and novel biomarkers to enhance diagnostic capabilities. Concluding with an assessment of Technology Readiness Levels, the paper emphasizes the transformative impact of non-WL colon CE devices on GI diagnostics, promising more precise, patient-centric, and accessible healthcare for GI disorders.

Thermal mapping: Assessing the optimal sites for temperature measurement in the human body and emerging technologies

Numerous body locations have been utilized to obtain an accurate body temperature. While some are commonly used, their accuracy, response time, invasiveness varies greatly, and determines their potential clinical and/or research use. This review discusses human body temperature locations, their accuracy, ease of use, advantages, and drawbacks. We explain the concept of core body temperature and which of the locations achieve the best correlation to this temperature. The body locations include axilla, oral cavity, rectum, digestive and urinary tracts, skin, tympanic, nasopharynx, esophagus, and pulmonary artery. The review also discusses the latest temperature technologies, heat-flux technology and telemetric ingestible temperature pills, and the body locations used to validate these devices. Rectal and esophageal measurements are the most frequently used.

Wearable and ingestible technology to evaluate and prevent exertional heat illness: A narrative review

Exertional heat illness remains a constant threat to the athlete, military service member, and laborer. Recent increases in the number and intensity of environmental heat waves places these populations at an ever increasing risk and can be deadly if not recognized and treated rapidly. For this reason, it is extremely important for medical providers to guide athletes, service members, and laborers in the implementation of awareness, education, and measures to reduce or mitigate the risk of exertional heat illness. Within the past 2 decades, a variety of wearable technology options have become commercially available to track an estimation of core temperature, yet questions continue to emerge as to its use, effectiveness, and practicality in athletics, the military, and the workforce. There is a paucity of data on the accuracy of many of these newer devices in the setting of true heat stroke physiology, and it is important to avoid overreliance on new wearable technology. Further research and improvement of this technology are critical to identify accuracy in the diagnosis and prevention of EHI.

Validity of the CALERA Research Sensor to Assess Body Core Temperature during Maximum Exercise in Patients with Heart Failure

(1) Background: It is important to monitor the body core temperature (Tc) of individuals with chronic heart failure (CHF) during rest or exercise, as they are susceptible to complications. Gastrointestinal capsules are a robust indicator of the Tc at rest and during exercise. A practical and non-invasive sensor called CALERA Research was recently introduced, promising accuracy, sensitivity, continuous real-time analysis, repeatability, and reproducibility. This study aimed to assess the validity of the CALERA Research sensor when monitoring patients with CHF during periods of rest, throughout brief cardiopulmonary exercise testing, and during their subsequent recovery. (2) Methods: Twelve male CHF patients volunteered to participate in a 70-min protocol in a laboratory at 28 °C and 39% relative humidity. After remaining calm for 20 min, they underwent a symptom-limited stress test combined with ergospirometry on a treadmill, followed by 40 min of seated recovery. The Tc was continuously monitored by both Tc devices. (3) Results: The Tc values from the CALERA Research sensor and the gastrointestinal sensor showed no associations at rest (r = 0.056, p = 0.154) and during exercise (r = -0.015, p = 0.829) and a weak association during recovery (r = 0.292, p < 0.001). The Cohen's effect size of the differences between the two Tc assessment methods for rest, exercise, and recovery was 1.04 (large), 0.18 (none), and 0.45 (small), respectively. The 95% limit of agreement for the CALERA Research sensor was -0.057 ± 1.03 °C. (4) Conclusions: The CALERA sensor is a practical and, potentially, promising device, but it does not provide an accurate Tc estimation in CHF patients at rest, during brief exercise testing, and during recovery.

Normal gastrointestinal temperature values measured through ingestible capsules technology: a systematic review

Climate change has amplified the importance of continuous and precise body core temperature (Tcore) monitoring in the everyday life. In this context, assessing Tcore through ingestible capsules technology, i.e., gastrointestinal temperature (Tgastrointestinal), emerges as a good alternative to prevent heat-related illness. Therefore, we conducted a systematic review to point out values of normal Tgastrointestinal measured through ingestible capsules in healthy humans. The study followed PRISMA guidelines and searched the PubMed and Scielo databases from 1971 to 2023. Our search strategy included the descriptors ("gastrointestinal temperature") AND ("measurement"), and eligible studies had to be written in English and measured Tgastrointestinal using ingestible capsules or sensors in healthy adults aged 18-59 at rest. Two pairs of researchers independently reviewed titles and abstracts and identified 35 relevant articles out of 1,088 in the initial search. An average value of 37.13 °C with a standard deviation of 0.24 °C was observed, independently of the gender. The values measured ranged from 36.70 °C to 37.69 °C. In conclusion, this systematic review pointed out the mean value of 37.13 ± 0.24 °C measured by ingestible capsules as reference for resting Tgastrointestinal in healthy adult individuals.