Heat transfer and loss by whole-body hyperthermia during severe lower-body heating are impaired in healthy older men

Brazaitis, Marius; Paulauskas, Henrikas; Eimantas, Nerijus; Obelienienė, Diana; Baranauskienė, Neringa; Skurvydas, Albertas

doi:10.1016/j.exger.2017.05.018

Cited by 16 publications

(24 citation statements)

References 39 publications

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“…We examined whether severe whole-body hyperthermia suppresses neuromuscular (central and peripheral) functions in older men more than in young men. Our primary finding was that despite delayed and weakened thermoregulation [2], and age-related decline in neuromuscular function, healthy aging preserved motor performance in severe wholebody hyperthermia. Aging shows an even greater lowerbody heating-induced increase in potentiation of the muscle torque development and spinal reflex loop conduction velocity.…”

Section: Resultsmentioning

confidence: 85%

“…Aiming at evading the effect of dietinduced thermogenesis, the subjects did not eat from 12 h before the start of the experiment until it ended. To standardize the condition of hydration and the feeling of thirst, subjects were allowed to drink still water if they wanted until 60 min before the first body mass measurement [2,10,36,37].…”

Section: Familiarization Sessionmentioning

confidence: 99%

“…As we age, motor performance [1] and thermoregulatory efficiency [2] progressively declines, creating job-related health and safety concerns. Age-related progressive decline in neuromuscular function, characterized by reduced force generating capacity, loss of muscle mass (sarcopenia) [3,4], loss of neuron fiber size and density [5], is highly predictive of frailty, disability, and mortality [6,7].…”

Section: Introductionmentioning

confidence: 99%

“…water bath) or indirect (e.g. water-perfused suit) external heating of older subjects and have focused on the direct effects of mild-tosevere whole-body hyperthermia (WBH) on the kinetics of physiological responses including body temperature [2], sweating efficiency [10], cardiovascular parameters [11,12], metabolic rate [2], heat gain [2,10], subjective sensation [13], and cognition [14]. To our knowledge, the functional consequences of severe WBH (rectal temperature increase from normal !1.5 C; Bain, Nybo [15]) on neurophysiological functions in healthy aged men have not been fully investigated.…”

Section: Introductionmentioning

confidence: 99%

“…Leaky RyR1 contributes to age-related loss of muscle function [32]. However, it can be expected that in older individuals, mainly because of attenuated thermoregulation [2] and muscle function [28,29] more heat will be accumulated and stored in the heated locations and the body core, resulting greater metabolically induced mitochondrial ROS production [33], leading to reduced Ca 2þ kinetics and overall loss of muscle function [30].…”

Section: Introductionmentioning

confidence: 99%

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Motor performance is preserved in healthy aged adults following severe whole-body hyperthermia

Brazaitis

Paulauskas

Eimantas

et al. 2018

International Journal of Hyperthermia

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Healthy aging is associated with a progressive decline in motor performance and thermoregulatory efficiency. Functional consequences of severe whole-body hyperthermia on neurophysiological functions in healthy aged men have not been investigated. To determine whether severe whole-body hyperthermia (increase in rectal temperature of about 2.5 C) induced by lower-body heating in older men (64-80 years, n ¼ 9) would suppress excitability of reflexes, voluntarily and electrically induced ankle plantar flexor contractile properties were compared with those in young men (19-21 years, n ¼ 11). Though no aging effect on hyperthermia-induced reflex amplitudes was observed, a decrease in maximal H-reflex and V-wave latencies was found to be greater in older than in young men. In older men, lower-body heating was accompanied by a significant increase in twitch and tetani test torque in parallel with a greater decrease in muscle contraction time. There was no temperaturedepended aging effect on the voluntary activation and maximal voluntary torque production. Despite delayed and weakened thermoregulation and age-related decline in neuromuscular function, motor performance in whole-body severe hyperthermia is apparently preserved in healthy aging. ARTICLE HISTORY

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Section: Resultsmentioning

confidence: 85%

Section: Familiarization Sessionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Motor performance is preserved in healthy aged adults following severe whole-body hyperthermia

Brazaitis

Paulauskas

Eimantas

et al. 2018

International Journal of Hyperthermia

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Linking the relationship between dietary folic acid intake and risk of osteoporosis among middle‐aged and older people: A nationwide population‐based study

Zhang,

Hu,

Wang

et al. 2024

Food Science & Nutrition

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Among middle‐aged and older people, balanced and nutritious diets are the foundation for maintaining bone health and preventing osteoporosis. This study is aimed at investigating the link between dietary folic acid intake and the risk of osteoporosis among middle‐aged and older people. A total of 20,686 people from the National Health and Nutritional Examination Survey (NHANES) 2007–2010 are screened and included, and 5312 people aged ≥45 years with integral data are ultimately enrolled in evaluation. Demographics and dietary intake‐related data are gathered and analyzed, and the odds ratio (OR) and 95% confidence interval (CI) of each tertile category of dietary folic acid intake and each unit increase in folic acid are assessed via multivariate logistic regression models. On this basis, the receiver operating characteristic (ROC) curve is used to identify the optimal cutoff value of dietary folic acid intake for indicating the risk of osteoporosis. Of 5312 people with a mean age of 62.4 ± 11.0 years old, a total of 513 people with osteoporosis are screened, and the dietary folic acid intake amount of the osteoporosis group is significantly lower than that of the non‐osteoporosis group (p < .001). The lowest tertile category is then used to act as a reference category, and a higher dietary folic acid intake amount is observed to be positively related to lower odds for risk of osteoporosis. This trend is also not changed in adjustments for combinations of different covariates (p all < .05). Based on this, a dietary folic acid intake of 475.5 μg/day is identified as an optimal cutoff value for revealing osteoporosis. Collectively, this nationwide population‐based study reveals that a higher daily dietary folic acid intake has potential protective effects on osteoporosis in middle‐aged and older people.

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Three different motor task strategies to assess neuromuscular adjustments during fatiguing muscle contractions in young and older men

et al. 2018

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Healthy aging is associated with a marked decline in motor performance. The functional consequences of applying varying novel or unexpected motor stimuli during intermittent isometric prolonged (fatiguing) motor tasks for lower limb neuromuscular fatigability and steadiness, perception of effort, and blood markers of stress in healthy aged men compared with young men have not been investigated. The participants in this study were 15 young men (aged 22 ± 4 years) and 10 older men (aged 67 ± 6 years). They performed 100 intermittent isometric knee extensions under three experimental conditions involving intermittent isometric contraction tasks according to constant, predictable, and unpredictable torque target sequences. The variability in maximal voluntary contraction averaged 50%, and was 25, 50, and 75% for the three strategies. All included a 5-s contraction and 20-s rest. The main variables were measured before exercise, after 100 repetitions, and 1 h after exercise. In all experimental trials, the decreases in the maximal voluntary contraction and central activation ratio, and the increases in effort sensation and muscle temperature, were smaller in older men than in younger men. The coefficient of variation during the motor performance did not differ between age groups. However, in all three strategies, the dopamine concentration was significantly higher in older than in younger men. The prolactin concentration did not differ significantly between age groups or conditions, although its decrease during loading correlated negatively with the central activation ratio.

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Heat transfer and loss by whole-body hyperthermia during severe lower-body heating are impaired in healthy older men

Cited by 16 publications

References 39 publications

Motor performance is preserved in healthy aged adults following severe whole-body hyperthermia

Motor performance is preserved in healthy aged adults following severe whole-body hyperthermia

Linking the relationship between dietary folic acid intake and risk of osteoporosis among middle‐aged and older people: A nationwide population‐based study

Three different motor task strategies to assess neuromuscular adjustments during fatiguing muscle contractions in young and older men

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