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Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study examined gender differences in the physical demands of British Army recruit training in 3 platoons with different gender compositions. Subjects wore heart rate monitors to measure cardiovascular strain and accelerometers to measure physical activity during weeks 1, 6, and 9 of the 12-week program. There was no difference in physical activity between platoons or genders (p > 0.05). In the mixed gender platoon, males operated at a lower cardiovascular strain than females (24 +/- 2 vs. 33 +/- 2% heart rate reserve (HRR), p < 0.001), probably because of their greater aerobic fitness (p < 0.001). Males in the mixed gender platoon experienced lower cardiovascular strain than the male-only platoon (24 +/- 2 vs. 33 +/- 2% HRR, p < 0.001). Females experienced the same degree of cardiovascular strain, irrespective of platoon (33 +/- 2 vs. 33 +/- 3% HRR, p = 0.814). The additional cardiovascular strain experienced by female recruits may increase fatigue and predisposition to overuse musculoskeletal injury.
Mil Med 2009 Aug
PMID:Gender differences in the physical demands of British Army recruit training. 1974 35

Recent research using functional magnetic resonance imaging has revealed that memory retrieval often places considerable demands on prefrontal cortex (PFC), a region known to underpin complex decision-making. Regional dissociations within PFC suggest that memory retrieval recruits several decision processes shared with complex decision making in non-memory domains. Here we briefly review data highlighting the role of dorsolateral prefrontal cortex (dlPFC) during memory and non-memory judgments, which suggest that dlPFC is sensitive to decision complexity during memory retrieval. As decision complexity increases, decision makers may be more susceptible to stress and/or fatigue with consequent failures of memory judgment.
Mil Psychol 2009 Jan 01
PMID:Rules Versus Evidence in Memory and Non-Memory Decision-Making. 2004 7

Since World War I, hypnosis has been used by U.S. military medical personnel to treat shell shock, battle fatigue, and traumatic neurosis. Most recently, hypnosis has also been effective in the treatment of Vietnam combat veterans with post-traumatic stress disorder. Additionally, over 30 years ago, the American Medical Association endorsed the use of hypnosis by physicians and the teaching of hypnosis in medical schools. However, even with this rich tradition, there remains an underutilization of hypnosis within medical and surgical settings. To encourage the use of hypnosis, this paper reviews current literature concerning the benefits of employing hypnosis and positive outcome suggestions with surgery patients in a military hospital. Case studies are also included that describe the applications of hypnosis as an adjunct to successful surgical procedures. Practitioners are encouraged to learn more about hypnosis so as to determine the efficacy of this therapeutic modality as an appropriate addition to their treatment armamentarium. A protocol for hypnotic induction and positive suggestions with surgery patients is also included.
Mil Med 1994 Apr
PMID:Hypnosis with the surgical patient. 2005 37

The study investigates stress levels and related behaviors of nurses in a military medical center during wartime. In 2007, nurses completed a questionnaire survey with objective validation of data in a subsample using actigraphy over 12 weeks. Of 270 nurses, 255 (94%) returned surveys. A total of 81% reported moderately high or high stress with sources listed as work (66%) and fatigue (39%). Many reported coming to work despite feeling ill and/or stressed (13.6 days/3 months). In contrast, morale was high or moderately high in 71%. Nurses reported an average of 5.5 hours of sleep/night, 8.8 h/wk taken for self, and 3.8 h/wk for exercise. Actigraphy data showed an average of 6.0 hours of sleep/night. These findings highlight a mismatch between stress levels and coping perceptions indicating an inability to properly care for self. To manage the effects of chronic stress, nurse leaders should implement systems targeting healthy life balance.
Mil Med 2010 Feb
PMID:Taking aim at nurse stress: a call to action. 2018 Apr 78

Prolonged, exhaustive exercise frequently leads to an increased incidence of upper respiratory tract illness (URTI) which is linked to transient immunodepression. We investigated potential biochemical markers of stress and fatigue, and URTI symptoms as a surrogate of immunodepression, in US Marines undergoing intensive winter training at altitude. Selected plasma amino acids and leptin (p[Lep]) were measured as possible markers of fatigue and immunodepression, together with nonesterified fatty acids (p[NEFA]) and total antioxidant capacity (p[TAC]). Changes were observed in plasma free tryptophan (p[FT]), p[Gln], p[Lep], p[NEFA], p[TAC] but not branched chain amino acids (p[BCAA]). p[FT] decreased markedly. Resting p[Gln] decreased overall after one month at altitude. p[Gln] routinely decreases 1-2 hrs after prolonged exercise. Importantly, we observed early morning decreases in p[Gln], suggesting a cumulative effect of prolonged activity, stress, and fatigue. Concomitantly, individuals with highest illness scores had the greatest p[Gln] decrease: low p[Gln] may therefore be associated with a diminished stress tolerance.
Mil Med 2010 Mar
PMID:Biochemical markers of possible immunodepression in military training in harsh environments. 2035 4

Assessing fitness for duty (FFD) typically requires expensive equipment and large time windows. Here we capitalize on basic principles of human time perception to build a portable software package that can quickly and efficiently test for excessive fatigue or traumatic brain injury. Time perception involves a collaboration of many brain areas, and we hypothesize that generalized damage to the brain can be rapidly assessed by subtle disorders in simple timing tasks. We aim to produce an inexpensive, portable device for rapid detection of fatigue or brain injury both in the clinic and on the field.
Mil Psychol 2009 Jan 01
PMID:Using Time Perception to Measure Fitness for Duty. 2045 42

Chronic fatigue/physical exhaustion (FPE) impacts combat readiness but is difficult to identify. We tested the hypothesis that resting heart rate variability (HRV), including both time- and frequency-domain assessments, would correlate with hydration status and aerobic capacity in military recruit-age men and women with varying fitness levels. Cardiac interbeat intervals were recorded using a heart R-R monitor during 20 minutes of quiet, supine rest with paced breathing (0.25 Hz). HRV metrics included average R-R interval (RRIavg), R-R interval standard deviation (RRISD), the percentage of adjacent R-R intervals varying by > or = 50 ms (pNN50), and integrated areas of R-R interval spectral power at the high (0.15-0.4 Hz) (RRIHF) and low (0.04-0.15 Hz) (RRILF) frequencies. Treadmill maximal oxygen uptake (VO2 max), segmental bioimpedance estimates of total body water (TBW), and urine specific gravity (USG) were also assessed. All dependent variables of interest were within expected ranges, although absolute ranges of individual values were considerable. RRI correlated with VO2 max (r = 0.49; p < 0.001), with TBW (r = 0.38; p < 0.001), and inversely with USG (r = -0.23; p = 0.02). RRISD correlated with VO2 max (r = 0.21; p = 0.03), but not with TBW or USG. pNN50 correlated inversely with USG (r = -0.21; p = 0.03) but not with VO2 max or TBW. R-R interval spectral power at the high and low frequencies did not correlate with VO2 max, TBW, or USG. We have demonstrated that fitness level and hydration status may affect cardiac function via changes in autonomic tone, highlighting the potential of field-based assessment of heart rate variability metrics to identify FPE and other aspects of combat readiness.
Mil Med 2009 May
PMID:Heart rate variability to assess combat readiness. 2073 Dec 79

Fatigue is known to impair cognitive performance, but it remains unclear whether concurrent common stressors affect cognitive performance similarly. We used the Stroop Color-Word Conflict Test to assess cognitive performance over 24 hours for four groups: control, sleep-deprived (SD), SD + energy deficit, and SD + energy deficit + fluid restricted. Fatigue levels were quantified using the Profile of Mood States (POMS) survey. Linear mixed-effects (LME) models allowed for testing of group-specific differences in cognitive performance while accounting for subject-level variation. Starting fatigue levels were similar among all groups, while 24-hour fatigue levels differed significantly. For each cognitive performance test, results were modeled separately. The simplest LME model contained a significant fixed-effects term for slope and intercept. Moreover, the simplest LME model used a single slope coefficient to fit data from all four groups, suggesting that loss in cognitive performance over a 24-hour duty cycle with respect to fatigue level is similar regardless of the cause.
Mil Med 2010 Dec
PMID:A comparison of cognitive performance decreases during acute, progressive fatigue arising from different concurrent stressors. 2126 97

Load carriage and muscular fatigue are two major stressors experienced by military recruits during basic training. The purpose of this study was to assess the influences of load carriage and muscular fatigue on ground reaction forces and ground reaction loading rates during walking. Eighteen healthy males performed the following tasks in order: unloaded and unfatigued walking, loaded and unfatigued walking, fatiguing exercise, loaded and fatigued walking, and unloaded and fatigued walking. The fatiguing exercise consisted of a series of metered step-ups and heel raises with a 16-kg rucksack. Loaded walking tasks were performed with a 32-kg rucksack. Two-way repeated measures analysis of variances were used to determine the effects of fatigue and load carriage on ground reaction forces and loading rates. Muscular fatigue has a significant influence on peak vertical ground reaction force and loading rate (p < 0.01). Load carriage has a significant influence on peak ground reaction forces and loading rates (p < 0.001). As both muscular fatigue and load carriage lead to large increases of ground reaction forces and loading rates, the high incidence of lower extremity overuse injuries in the military may be associated with muscular fatigue and load carriage.
Mil Med 2012 Feb
PMID:Influence of fatigue and load carriage on mechanical loading during walking. 2236 59

This study examined the effect of body armor during repeated, intermittent high-intensity simulated military work. Twelve males performed 11 repetitions of a military style circuit, wearing no armor on one occasion and full armor (approximately 17 kg) on another. Performance was measured by the time to complete individual work tasks plus overall circuit time to completion. Heart rate, intestinal temperature, and rating of perceived exertion were recorded after each circuit. Participants' circuit time to completion was 7.3 +/- 1.0 seconds slower (p <0.01) when wearing armor. Shooting, vaulting, and crawling were also slower (0.8 +/- 0.2, 0.4 +/- 0.2, and 1.0 +/- 0.4 seconds, respectively; all p < or = 0.05). No differences were observed for box lifting. Higher core temperatures were reported for the armor condition for circuit's 7 to 11 (p = 0.01-0.05). Rating of perceived exertion was higher (1 +/- 0; p = 0.03) when wearing armor. No differences were observed for heart rate. Wearing armor impairs repeated high-intensity military task performance. In the relatively short work time utilized, this decrement did not accrue over time. The impairment may, then, be related to the armor load, rather than accumulating fatigue.
Mil Med 2012 Nov
PMID:Body armor, performance, and physiology during repeated high-intensity work tasks. 2319 6


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