Evaluation of physiological and psychophysical strain of security guards wearing stab-resistant body armor under a simulated patrol condition

2021 ◽  
pp. 004051752110066
Author(s):  
Jie Yang ◽  
Qiqi An ◽  
Yuchen Wei ◽  
Mengqi Yuan
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Skin Temperature ◽  
Core Temperature ◽  
Heat Storage ◽  
Body Armor ◽  
Sweat Loss ◽  
Security Guards ◽  
Significant Difference ◽  
Body Heat

This study aimed to determine the effects of stab-resistant body armor (SRBA) on the physiological and psychophysical strain of security guards. Ten volunteers performed a 50-min treadmill walk at 7.0 km/h in a climate chamber where the ambient temperature and relative humidity were controlled to 40 °C and 40%, respectively. All the participants performed the walk under two experimental conditions: wearing a uniform without (CON) and with armor (SRBA). Several physiological responses (core temperature, skin temperature, heart rate, and oxygen consumption) and psychophysical parameters (thermal sensation vote, thermal comfort vote, ratings of perceived exertion, and clothing and skin wetness) were recorded during the trials. Furthermore, the sweat loss, body heat storage, and physiological strain index (PSI) were calculated based on the measurements. The results indicated no significant difference between the SRBA and CON groups in terms of core temperature, mean skin temperature, heart rate, oxygen consumption, body heat storage, or PSI over time. However, a significant difference ( p < 0.05) between the two trials was observed in terms of scapula skin temperature (40 and 45 min) and body temperature (0 and 45 min). Moreover, the SRBA (3.5 kg and 17% body area coverage) caused an 11% increase in sweat loss, but a 27% reduction in sweating efficiency. Although the armor caused slight discomfort, wetness, and exertion, no significant difference between the two trials was observed in terms of the psychophysical responses. Therefore, the SRBA imposed negligible physiological and psychophysical strain during the 50-min walk in this case.

scholarly journals Sex-Related Differences in the Maximal Lactate Steady State

Sports ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 154 ◽  
Author(s):  
Paul Hafen ◽  
Pat Vehrs
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Steady State ◽  
Respiratory Exchange Ratio ◽  
Time To Exhaustion ◽  
Distance Runners ◽  
Maximal Lactate Steady State ◽  
Training Tool ◽  
Significant Difference ◽  
Males And Females

The maximal lactate steady state (MLSS) is one of the factors that differentiates performance in aerobic events. The purpose of this study was to investigate the sex differences in oxygen consumption (VO2), heart rate (HR), and the respiratory exchange ratio (RER) at the MLSS in well-trained distance runners. Twenty-two (12 female, 10 male) well-trained distance runners (23 ± 5.0 years) performed multiple 30-min steady-state runs to determine their MLSS, during which blood lactate and respiratory gas exchange measures were taken. To interpret the MLSS intensity as a training tool, runners completed a time-to-exhaustion (TTE) run at their MLSS. The relative intensity at which the MLSS occurred was identical between males and females according to both oxygen consumption (83 ± 5 %O2max) and heart rate (89 ± 7 %HRmax). However, female runners displayed a significantly lower RER at MLSS compared to male runners (p < 0.0001; 0.84 ± 0.02 vs. 0.88 ± 0.04, respectively). There was not a significant difference in TTE at MLSS between males (79 ± 17 min) and females (80 ± 25 min). Due to the observed difference in the RER at the MLSS, it is suggested that RER derived estimates of MLSS be sex-specific. While the RER data suggest that the MLSS represents different metabolic intensities for males and females, the relative training load of MLSS appears to be similar in males and female runners.

scholarly journals Acute adjustments of heart rate and oxygen consuption in an experimental protocol of step training with diferent combinations of platform height and musical rhythms - doi: 10.4025/actascihealthsci.v35i2.11669

2013 ◽  
Vol 35 (2) ◽  
pp. 181 ◽  
Author(s):  
Viviane Ribeiro de Ávila ◽  
Renato Duarte Frade ◽  
Vinicius De Oliveira Damasceno ◽  
Jeferson Vianna ◽  
Jorge Roberto Perrout de Lima ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Heart Rate ◽  
Body Weight ◽  
Oxygen Consumption ◽  
Metabolic Responses ◽  
Experimental Protocol ◽  
Fat Percentage ◽  
Musical Rhythm ◽  
Significant Difference ◽  
Musical Rhythms

The aim of this study was to investigate adaptations acute heart rate (HR) and oxygen consumption (VO2) in an experimental protocol of step training with different combinations of platform height (15.2, 20.3 and 25.4 cm) and musical rhythms (125, 135 and 145 bpm). Thirty-five women were randomly selected, (mean ± DP) aged 21.6 ± 1.8 years, body weight of 57.8 ± 8.2 kg, height of 162.6 ± 6.8 cm, body mass index of 21.8 ± 2.5 kg m-2 and fat percentage (% Fat) of 24.8 ± 4.4%, with at least six months experience in step training sessions, and a frequency of at least two days a week. Techniques of descriptive and inferential statistics were employed. A significant difference was detected for the HR and VO2 in relation to the increase in step platform height and in musical rhythm for all the combinations, except for three situations. From the obtained results, we can infer that the cardiovascular and metabolic responses increase or decrease according to the musical rhythm and/or platform height.  

Relationship between body heat content and finger temperature during cold exposure

2001 ◽  
Vol 90 (6) ◽  
pp. 2445-2452 ◽  
Author(s):  
Dragan Brajkovic ◽  
Michel B. Ducharme ◽  
John Frim
Keyword(s):  
Skin Temperature ◽  
Heat Storage ◽  
Heat Content ◽  
The Body ◽  
Finger Temperature ◽  
Finger Dexterity ◽  
The Relationship ◽  
Finger Skin ◽  
Body Heat ◽  
Partitional Calorimetry

The purpose of the present experiment was to examine the relationship between rate of body heat storage (S˙), change in body heat content (ΔHb), extremity temperatures, and finger dexterity. S˙, ΔHb , finger skin temperature (Tfing), toe skin temperature, finger dexterity, and rectal temperature were measured during active torso heating while the subjects sat in a chair and were exposed to −25°C air. S˙ and ΔHb were measured using partitional calorimetry, rather than thermometry, which was used in the majority of previous studies. Eight men were exposed to four conditions in which the clothing covering the body or the level of torso heating was modified. After 3 h, Tfing was 34.9 ± 0.4, 31.2 ± 1.2, 18.3 ± 3.1, and 12.1 ± 0.5°C for the four conditions, whereas finger dexterity decreased by 0, 0, 26, and 39%, respectively. In contrast to some past studies, extremity comfort can be maintained, despite S˙ that is slightly negative. This study also found a direct linear relationship between ΔHb and Tfing and toe skin temperature at a negative ΔHb. In addition, ΔHb was a better indicator of the relative changes in extremity temperatures and finger dexterity over time than S˙.

Reduced stress- and cold-induced increase in energy expenditure in interleukin-6-deficient mice

2006 ◽  
Vol 291 (3) ◽  
pp. R551-R557 ◽  
Author(s):  
Ingrid Wernstedt ◽  
Amanda Edgley ◽  
Anna Berndtsson ◽  
Jenny Fäldt ◽  
Göran Bergström ◽  
...  
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Energy Expenditure ◽  
Core Temperature ◽  
Cold Exposure ◽  
Interleukin 6 ◽  
Utilization Rate ◽  
Sympathetic Outflow ◽  
Wild Type ◽  
Deficient Mice

Interleukin-6 (IL-6) deficient (-/-) mice develop mature onset obesity. Pharmacological studies have shown that IL-6 has direct lipolytic effects and when administered centrally increases sympathetic outflow. However, the metabolic functions of endogenous IL-6 are not fully elucidated. We aimed to investigate the effect of IL-6 deficiency with respect to cold exposure and cage-switch stress, that is, situations that normally increase sympathetic outflow. Energy metabolism, core temperature, heart rate, and activity were investigated in young preobese IL-6−/− mice by indirect calorimetry together with telemetry. Baseline measurements and the effect of cage-switch stress were investigated at thermoneutrality (30°C) and at room temperature (20°C). The effect of cold exposure was investigated at 4°C. At 30°C, the basal core temperature was 0.6 ± 0.24°C lower in IL-6−/− compared with wild-type mice, whereas the oxygen consumption did not differ significantly. The respiratory exchange ratio at 20°C was significantly higher and the calculated fat utilization rate was lower in IL-6−/− mice. In response to cage-switch stress, the increase in oxygen consumption at both 30 and 20°C was lower in IL-6−/− than in wild-type mice. The increase in heart rate was lower in IL-6−/− mice at 30°C. At 4°C, both the oxygen consumption and core temperature were lower in IL-6−/− compared with wild-type mice, suggesting a lower cold-induced thermogenesis in IL-6−/− mice. The present results indicate that endogenous IL-6 is of importance for stress- and cold-induced energy expenditure in mice.

Body Composition (% Fat) and Heat Stress of Well Conditioned Young Adult Males

1982 ◽  
Vol 26 (6) ◽  
pp. 561-564
Author(s):  
Michael W. Riley ◽  
David J. Cochran ◽  
Arthur J. Soundy
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Young Adult ◽  
Skin Temperature ◽  
Body Fat ◽  
Bicycle Ergometer ◽  
The Body ◽  
Lean Body Weight ◽  
Adult Males ◽  
Young Adult Males

The physiological responses of heart rate, oxygen consumption, sweat loss, rectal temperature and mean skin temperature were monitored as eight well-conditioned young adult males were exposed to effective temperatures of 70°F, 80°F and 90°F. The body fat contents of the subjects ranged from 11.3% to 34%. The subjects pedalled a 300 kilopond meters/minute load on a bicycle ergometer for 25 minutes. Results indicate that body fat or the percent of body fat squared have a statistically significant effect on the dependent variables of oxygen consumption/lean body weight, change in heart rate, core-skin temperature gradient, and oxygen consumption/maximum oxygen consumption.

scholarly journals Tracking Changes in Maximal Oxygen Consumption with the Heart Rate Index in Female Collegiate Soccer Players

2014 ◽  
Vol 42 (1) ◽  
pp. 103-111 ◽  
Author(s):  
Michael R. Esco ◽  
Ronald L. Snarr ◽  
Andrew Flatt ◽  
Matthew Leatherwood ◽  
Adam Whittaker
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Endurance Training ◽  
Maximal Exercise ◽  
Maximal Oxygen Consumption ◽  
Soccer Players ◽  
Maximal Exercise Test ◽  
Significant Difference ◽  
The Difference ◽  
Training Protocol

Abstract The purpose of this study was to determine if the HRindex Method (VO2max = [6 x HRindex - 5] x 3.5, where HRindex = HRmax/HRrest) was accurate for tracking changes in VO2max following 8-weeks of endurance training among collegiate female soccer players. Predicted VO2max via the HRindex Method and observed VO2max from a maximal exercise test on a treadmill were determined for a group of female soccer athletes (n = 15) before and following an 8-week endurance training protocol. The predicted (pVO2max) and observed (aVO2max) values were compared at baseline and within 1-week post-training. Change values (i.e., the difference between pre to post) for each variable were also determined and compared. There was a significant difference between aVO2max before (43.2 ± 2.8 ml.kg.min-1) and following (46.2 ± 2.1 ml.kg.min-1) the 8-week training program (p < 0.05). However, pVO2max did not significantly change following training (pre = 43.4 ± 4.6 ml.kg.min-1, post = 42.9 ± 4.1 ml.kg.min-1, p = 0.53). Furthermore, the correlation between the change in aVO2max and the change in pVO2max was trivial and non-significant (r = 0.30, p = 0.28). The HRindex Method does not appear to be suitable for predicting changes in VO2max following 8-weeks of endurance training in female collegiate soccer players

scholarly journals Relationship Between Heart Rate, Oxygen Consumption, and Energy Expenditure in Futsal

2021 ◽  
Vol 12 ◽  
Author(s):  
Henrique Santos da Silva ◽  
Fabio Yuzo Nakamura ◽  
Marcelo Papoti ◽  
Alexsandro Santos da Silva ◽  
Julio Wilson Dos-Santos
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Energy Expenditure ◽  
Treadmill Running ◽  
Concordance Correlation ◽  
Altman Plot ◽  
Metabolic Equivalents ◽  
Significant Difference ◽  
Continuous Test ◽  
Good Individual

The primary aim of this study was to compare the measured oxygen consumption (Measured-VO2) in a simulated futsal game (S-Game) with the estimated oxygen consumption (Estimated-VO2) through a regression equation between heart rate (HR) and oxygen consumption (VO2) (HR-VO2) in treadmill running, and a secondary aim was to calculate the total energy expenditure (EE) in S-Game. Ten professional players (22.20 ± 3.22 years) were evaluated. HR-VO2 was determined individually in the continuous test on the treadmill (ContTest). The Measured-VO2 in S-Game was compared with the Estimated-VO2 in the ContTest. Alactic and lactic pathways were estimated by VO2. The Estimated-VO2 presented no statistically significant difference with the Measured-VO2, using the paired t-test (p = 0.38). However, the correlation between Estimated- and Measured-VO2 was very weak (r = −0.05), and it presented poor agreement (concordance correlation coefficient = −0.04). In addition, a Bland–Altman plot presented bias of −2.8 ml/kg/min and individual difference as large as 19 ml/kg/min. The HR-VO2 determined by the ContTest was not a good individual predictor of VO2. The high intensity and intermittent nature of the futsal game possibly caused dissociation in the HR-VO2 relationship. ContTest is not recommended for estimating VO2 and calculating individual EE in the futsal game. This is recommended only for the group mean. The total EE in S-Game was 13.10 ± 1.25 kcal.min−1 (10.81 ± 1.57 metabolic equivalents). The contributions from the metabolic pathways were as follows: aerobic (93%), alactic (5%), and lactic (2%).

Effect of vapor pressure on physiologic strain and body heat storage

1963 ◽  
Vol 18 (4) ◽  
pp. 808-811 ◽  
Author(s):  
John F. Hall
Keyword(s):  
Heart Rate ◽  
Heat Stress ◽  
Vapor Pressure ◽  
Heat Storage ◽  
Sweat Rate ◽  
Human Subjects ◽  
Vapor Pressures ◽  
Physiologic Responses ◽  
Male Subjects ◽  
Body Heat

Physiologic strain, in terms of body heat storage, and other physiologic responses were measured and compared in two series of heat stress experiments performed on human subjects exposed to different ambient vapor pressures. One group of 75 experiments conducted on 5 healthy nonacclimatized male subjects exposed 5 times each to 38, 54, and 71 C at 10 mm Hg vapor pressure was compared with a series of 81 experiments performed on 10 similar subjects exposed 1–6 times each to 38, 41, and 54 C at 20 mm Hg vapor pressure. Subjects were sitting and wore 1.0 clo insulation. The data show relation between body heat storage and a) the modified Craig index of physiologic strain; b) over-all sweat rate; c) evaporative rate; d) sweat-evaporative ratio; e) mean skin and rectal temperatures; and f) change of heart rate at the respective vapor pressure levels. Statistically significant correlation between sweat-evaporative ratio and over-all sweat rate with body heat storage is shown. Use of the over-all sweat response as a physiologic strain index is suggested. Submitted on August 14, 1962

scholarly journals Thermal behavior alleviates thermal discomfort during steady-state exercise without affecting whole body heat loss

2019 ◽  
Vol 127 (4) ◽  
pp. 984-994 ◽  
Author(s):  
Nicole T. Vargas ◽  
Christopher L. Chapman ◽  
Blair D. Johnson ◽  
Rob Gathercole ◽  
Matthew N. Cramer ◽  
...  
Keyword(s):  
Light Intensity ◽  
Thermal Behavior ◽  
Skin Temperature ◽  
Heat Loss ◽  
Core Temperature ◽  
Upper Body ◽  
Whole Body ◽  
Mean Skin Temperature ◽  
Thermal Discomfort ◽  
Body Heat

We tested the hypothesis that thermal behavior resulting in reductions in mean skin temperature alleviates thermal discomfort and mitigates the rise in core temperature during light-intensity exercise. In a 27 ± 0°C, 48 ± 6% relative humidity environment, 12 healthy subjects (6 men, 6 women) completed 60 min of recumbent cycling. In both trials, subjects wore a water-perfused suit top continually perfusing 34 ± 0°C water. In the behavior trial, subjects maintained their upper body thermally comfortable by pressing a button to perfuse cool water (2.2 ± 0.5°C) through the top for 2 min per button press. Metabolic heat production (control: 404 ± 52 W, behavior: 397 ± 65 W; P = 0.44) was similar between trials. Mean skin temperature was reduced in the behavior trial (by −2.1 ± 1.8°C, P < 0.01) because of voluntary reductions in water-perfused top temperature ( P < 0.01). Whole body ( P = 0.02) and local sweat rates were lower in the behavior trial ( P ≤ 0.05). Absolute core temperature was similar ( P ≥ 0.30); however, the change in core temperature was greater in the behavior trial after 40 min of exercise ( P ≤ 0.03). Partitional calorimetry did not reveal any differences in cumulative heat storage (control: 554 ± 229, behavior: 544 ± 283 kJ; P = 0.90). Thermal behavior alleviated whole body thermal discomfort during exercise (by −1.17 ± 0.40 arbitrary units, P < 0.01). Despite lower evaporative cooling in the behavior trial, similar heat loss was achieved by voluntarily employing convective cooling. Therefore, thermal behavior resulting in large reductions in skin temperature is effective at alleviating thermal discomfort during exercise without affecting whole body heat loss. NEW & NOTEWORTHY This study aimed to determine the effectiveness of thermal behavior in maintaining thermal comfort during exercise by allowing subjects to voluntarily cool their torso and upper limbs with 2°C water throughout a light-intensity exercise protocol. We show that voluntary cooling of the upper body alleviates thermal discomfort while maintaining heat balance through convective rather than evaporative means of heat loss.

Effect of Different Types of Lower-limb Exercise on Blood Pressure in Hypertensive People: A Randomized, Double-blind Controlled Clinical Trial

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Rozita Hedayti ◽  
Salimeh Mahmoodi ◽  
Rasool Bagheri ◽  
Marjan Biglary ◽  
Amir Hoshang Bakhtiary ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Oxygen Consumption ◽  
Diastolic Blood Pressure ◽  
Controlled Clinical Trial ◽  
Maximum Oxygen Consumption ◽  
Exercise Interventions ◽  
Concentric Exercise ◽  
Significant Difference

Objectives: The current study aimed at determining the immediate and long-lasting effects of eccentric and concentric exercises on hypertension in individuals with high blood pressure. Methods: A total of 45 hypertensive volunteers were randomly assigned to three intervention groups as eccentric exercise (n = 15), concentric exercise (n = 15), and control (n = 15) groups. All the volunteers underwent exercise interventions for four weeks, three sessions per week (12 sessions in total) as treadmill walking with +10% gradient (concentric group), -10% gradient (eccentric group), or neutral gradient. Before the intervention, immediately after the first session of the intervention, after the end of the intervention, and 48 hours after the end of the intervention, systolic and diastolic blood pressure, heart rate, and maximum oxygen consumption were measured and compared between the groups. Results: The positive gradient group had higher diastolic blood pressure 48 h after the intervention than the negative and neutral gradient groups (P < 0.05). There was no significant difference in the other study variables between eccentric and concentric exercise groups (P > 0.05). Statistical analysis showed that eccentric exercises immediately reduced systolic and diastolic blood pressure (P < 0.05). Eccentric and constrictive exercises reduced systolic and diastolic blood pressure for the long term (P < 0.05). Exonerative and constrictive exercises improved the heart rate, maximum oxygen consumption, and systolic blood and diastolic blood pressure in the short and long term (P < 0.05). Conclusions: Eccentric and concentric exercises with immediate and long-lasting effects improved systolic and diastolic blood pressure, as well as heart rate and maximum oxygen consumption. No significant difference was found between the two types of exercises in terms of the variables studied.

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