Validity of heart rate derived core temperature estimation during simulated firefighting tasks.

Rectal core temperature monitoring can help fire services mitigate heat injury but can be invasive and impractical. EQ02 + LifeMonitor provides a non-invasive estimation of core temperature. Therefore, the primary purpose of this study was to determine the validity of the EQ02 + LifeMonitor compared to the gold standard rectal thermometer core temperature assessment, as well as the potential influence of turnout gear on the estimated and physiological strain experienced during these activities. Thirteen participants completed simulated firefighting tasks with and without turnout gear, involving four rounds of a 5-min walk on a treadmill at 2.8 mph/2.5% grade and 20 deadlifts over 5 min in an environmental chamber set to 40.6 °C; 50% humidity. During each trial participants wore both an EQ02 + LifeMonitor and DataTherm II rectal thermometer. The results from the devices were statistically equivalent (p < 0.001), yet there was a statistically significant difference in the value (~ 0.1 °C; p < 0.001). There was a significant effect of devices [p < 0.001] and time [p < 0.001], but no interaction effect [p = 0.70] on core temperature drift. Estimated core temperature was marginally different from that measured via the DataTherm II. The EQ02 on average overestimated core temperature. Heart rate, rating of perceived exertion, and area under the curve of core temperature were significantly elevated due to turnout gear [ps < 0.025], but not core temperature skin temperature, or ventilatory rate [ps > 0.372]. These results suggest the EQ02 + LifeMonitor may be a viable, non-invasive alternative for assessing core temperature compared to rectal temperature monitoring, especially during rigorous, intermittent activities. Turnout gear does however increase heart rate, cumulative core temperature, and perceived exertion. Additionally, the validity of the estimated core temperature is not impacted by the use turnout gear. This is likely due to significant changes in heart rate, which allowed the heart-rate derived estimate of core temperature to remain consistent with changes in DataTherm II rectal temperatures.

Long-term voluntary wheel running effects on markers of long interspersed nuclear element-1 in skeletal muscle, liver, and brain tissue of female rats.

We sought to determine the effects of long-term voluntary wheel running on markers of long interspersed nuclear element-1 (L1) in skeletal muscle, liver, and the hippocampus of female rats. In addition, markers of the cGAS-STING DNA-sensing pathway that results in inflammation were interrogated. Female Lewis rats (n = 34) were separated into one of three groups including a 6-mo-old group to serve as a young comparator group (CTL, n = 10), a group that had access to a running wheel for voluntary wheel running (EX, n = 12), and an age-matched group that did not (SED, n = 12). Both SED and EX groups were carried out from 6 mo to 15 mo of age. There were no significant differences in L1 mRNA expression for any of the tissues between groups. Methylation of the L1 promoter in the soleus and hippocampus was significantly higher in SED and EX than in CTL group (P < 0.05). ORF1p expression was higher in older SED and EX rats than in CTL rats for every tissue (P < 0.05). There were no differences between groups for L1 mRNA or cGAS-STING pathway markers. Our results suggest there is an increased ORF1 protein expression across tissues with aging that is not mitigated by voluntary wheel running. In addition, although previous data imply that L1 methylation changes may play a role in acute exercise for L1 RNA expression, this does not seem to occur during extended periods of voluntary wheel running.

Systematic review and meta-analyses on the effects of whole-body vibration on bone health.

OBJECTIVE: To determine whole body vibration influence on human bone density and bone biomarkers. METHODS: We identified studies in Medline, Web of Science, Cumulative Index of Nursing and Allied Health, SPORTDiscus, Embase and Cochrane from inception to November 2021. Human randomized controlled trials involving commercially available whole body vibration platforms were included. Outcomes included bone density mean difference and serum concentrations of biomarkers (Procollagen type 1 N-terminal Propeptides, Osteocalcin, Bone specific alkaline phosphatase, and C-terminal Telopeptide of type 1 collagen). Random effects model (Hedges' g effect-size metric and 95% confidence-intervals) compared whole body vibration effect on bone density and bone biomarkers. Moderator analyses assessed health status, age, menopausal status, vibration type, vibration frequency, and study duration influence. RESULTS: Meta-analysis of 30 studies revealed bone density improvement after whole body vibration (Hedges' g = 0.11; p = 0.05; 95% CI = 0.00, 0.22). Whole body vibration improved bone density in healthy (Hedges' g = 0.10; p = 0.01; 95% CI = 0.02, 0.17) and postmenopausal women (Hedges' g = 0.09; p = 0.02; 95% CI = 0.01, 0.18). Bone density also increased following side-alternating whole body vibration intervention (Hedges' g = 0.21; p = 0.02; 95% CI = 0.04, 0.37). Whole body vibration had no significant effect on either bone formation biomarkers (Hedges' g = 0.22; p = 0.01; 95% CI = 0.05, 0.40) or bone resorption biomarkers (Hedges' g = 0.03; p = 0.74; 95% CI = -0.17, 0.23). CONCLUSION: Whole body vibration may be clinically useful as non-pharmacological/adjunct therapy to mitigate osteoporosis risk in healthy postmenopausal females. Additional studies are needed to determine the underlying mechanisms.