Subjective Activity Level Research Articles

Acute mountain sickness in disability and adaptive sports: Preliminary data

Acute mountain sickness (AMS) is a frequent complication for military personnel, veterans, athletes, and travelers at high altitudes. Symptoms may occur in individuals with less cerebrospinal fluid volume and less ability to accommodate increased brain volume. No studies on AMS exist in individuals with neurological impairments. We studied 64 subjects, including active and sedentary controls and those with tetraplegia, paraplegia, multiple sclerosis, and traumatic brain injury at the 2007 National Veterans Winter Sports Clinic in Snowmass, Colorado. Subjects completed three Lake Louise Score surveys to quantify symptoms. We found a higher than expected occurrence of AMS overall (51.6%) but no differences among groups, and few participants sought treatment. Fatigue and weakness were common symptoms. High subject activity levels may explain these findings. More research is warranted on larger sample sizes and on preventative medications and treatments for AMS, especially since many military personnel with neurological impairments are returning to full active service.

Effect of Physical Activity on Cytokine Levels

PURPOSE: Acute exercise appears to modulate cytokine response. To date however no one has evaluated the effect of chronic level of activity on cytokine response. We evaluated the effect of average weekly level of moderate to vigorous activity on serum Interleuken-1β (IL-1β), IL-10, Tumor Necrosis Factor alpha (TNF-α) and the arachadonic acid metabolite, Lipoxin (LX) (which down-regulates neutrophilic response). METHODS: The subjects were comprised of 11 healthy individuals whose mean age, weight, height, and body mass index were 37.5±7 years, 157.3±31.9 pounds, 68.34±4.4 inches and 23.5±2.2 kg/m2, respectively. Subject activity level was recorded by accelerometry and categorized as mild, moderate, or vigorous. Blood was drawn after one week of recorded activity level and analyzed for cytokines. Statistical analysis included the Pearson correlation coefficients between level of activity and cytokine levels. RESULTS: A negative correlation (r) was seen between the cytokine levels and activity. The r values and the means and standard deviations for moderate to vigorous activity and cytokines are shown in table 1.TableCONCLUSION: While the results did not reach statistical significance, this small pilot study suggests a negative correlation between cytokine levels (IL-10, IL-1β, TNF-α, and LX) and moderate to vigorous activity. Larger studies are needed to further validate this finding. Support: SIU School of Medicine Central Research Committee

Assessment of Habitual Physical Activity and Paretic Arm Mobility Among Stroke Survivors by Accelerometry

A major goal for many stroke survivors is a return to ambulatory activities, but there is not much known about the physical activity profiles of stroke survivors. Improved function in the paretic arm is also a major goal of rehabilitation, but there are few good measures of daily arm use. Accelerometers are devices that measure body movements in terms of acceleration. Accelerometers have been found to be useful indicators of movement in a number of studies involving different patient populations. They are able to detect habitual physical activity levels in subjects with low levels or activity and altered gait patterns. Different systems of multiple accelerometers have been used successfully to detect arm usage in individuals with hemiparesis from stroke, as well as with other disabilities that affect the upper extremities.

Relationship of the menstrual cycle phase to anterior cruciate ligament injuries in teenaged female athletes

Anterior cruciate ligament (ACL) injuries are more common among female athletes compared to male athletes. Several studies have been reported to explain the gender difference in ACL injury rates and several risk factors underlying gender disparity are believed to exist. Hormonal effects are considered to be one of the etiological factors for female non-contact ACL injuries. The objectives of this study were to determine if ACL injuries occurred randomly or correlated with a specific phase of the female menstrual cycle in teenaged female athletes and then to determine if pre-menstrual and menstrual dysfunctions influenced these ACL injuries. Eighteen of 37 consecutive female athletes, with ACL injuries, met the study criteria: teenage, with regular menstrual cycle, and non-contact injury. The menstrual history, athletic activity, and injury history were collected. Seventy-two percent of the subjects had premenstrual symptoms and 83% had menstrual symptoms. The subjective activity level at the follicular phase was significantly lowest between the phases. A significant statistical association was found between the phase of the menstrual cycle and ACL injuries (P = 0.0002). There were more injuries in the ovulatory phase than expected, and fewer injuries occurred in the other phases. The results showed a significant increase in non-contact ACL injuries in teenage female athletes during the ovulatory phase of the menstrual cycle and the subjective activity level and the premenstrual and menstrual symptoms might not affect the likelihood of the injuries. These findings suggest that sex hormones might play a role in the incidence of female non-contact ACL injuries.

Estimating under-reporting of energy intake in dietary surveys using an individualised method

Under-reporting (UR) of energy intake (EI) by self-reported dietary methods is well-documented but the methods used to estimate UR in population-based studies commonly assume a sedentary lifestyle. We compared estimated UR using individualised estimates of energy requirements with a population cut-off based on minimum energy needs. UR was estimated for 1551 adults aged 19-64 years enrolled in the National Diet and Nutrition Survey. Physical activity diaries and 7 d weighed dietary records were completed concurrently. Mean daily EI (kJ/d) was calculated from the dietary records. Reported physical activity was used to assign each subject's activity level, and then to calculate estimated energy requirements (EER) from published equations. UR was calculated both as EER - EI with an adjustment for daily EER and EI variation, and also by a population method. By the individual method UR was approximately 27 % of energy needs in men and 29 % in women, with 75 % of men and 77 % of women classified as under-reporters; by the population method 80 and 88 % were classified as under-reporters respectively. When subjects who reported their eating being affected by dieting or illness during dietary recording were excluded, UR was 25 % of energy needs in both sexes. UR was higher in overweight and obese men and women compared with their lean counterparts (P < 0.001). UR of EI must be considered in dietary surveys. The EER method allows UR to be quantified and takes into account an individual's activity level. Measures of physical activity and questions to identify under-eating during dietary recording may help to evaluate secular trends in UR.

Research on fatigue in children and adolescents with cancer

Second, we need a better understanding of the causes of cancer-related fatigue. Until we possess that information, attempts to prevent and treat fatigue will not be most effective because our interventions cannot be directed toward the causes. Biological markers of fatigue are also needed. This means more laboratory and clinical physiologic research and more objective measures of outcomes. The research team is moving in this direction with the use of actigraphy to measure sleep and activity levels in subjects. Third, more intervention-testing research is needed to provide the evidence-based clinical practice guidelines that offer the best hope for managing this clinical problem. The Pediatric Cooperative Group provides a structure for multisite clinical trials in which this intervention-testing research can be conducted. SUMMARY

The sensitivity and specificity of the Goldberg cut-off for EI:BMR for identifying diet reports of poor validity.

To explore the specificity and sensitivity of the Goldberg cut-off for EI:BMR for identifying diet reports of poor validity as compared with the direct comparison of energy intake with energy expenditure measured by doubly-labelled water. Twenty-two studies with measurements of total energy expenditure by doubly-labelled water (EE), basal metabolic rate (BMR) and energy intake (EI) provided the database (n=429). The ratio EI:EE provided the baseline definition of under- (UR), acceptable- (AR) and over-reporters (OR), respectively EI:EE <0.76, 0.76-1.24 and >1.24. Four strategies for identifying under- and over-reporters using the Goldberg cut-off were explored. Sensitivity of the cut-off was calculated as the proportion of UR correctly identified and specificity as the proportion of non-UR correctly identified. UR, AR and OR (by EI:EE) were 34, 62 and 4% respectively of all subjects. When a single Goldberg cut-off for the physical activity level (PAL) of 1.55 was used, for men and women respectively the sensitivity was 0.50 and 0.52 and the specificity 1. 00 and 0.99. Using a cut-off for higher PAL traded specificity for sensitivity. Using the cut-off for a PAL of 1.95, sensitivity was 0. 76 and 0.85 and the specificity 0.87 and 0.78 for men and women respectively. Using cut-offs for mean age-sex specific PAL did not improve sensitivity. When subjects were assigned to low, medium and high activity levels and cut-offs for three different PALs used, sensitivity improved to 0.74 and 0.67 without loss of specificity (0. 97 and 0.98), for men and women respectively. If activity levels for men were applied to the womens' data, sensitivity improved to 0.72. To identify diet reports of poor validity using the Goldberg cut-off for EI:BMR, information is needed on each subject's activity level.

Airway Surface Irregularities Promote Particle Diffusion in the Human Lung

Current NCRP and ICRP particle deposition models employed in risk assessment analyses treat the airways of the human lung as smooth-walled tubes. However, the upper airways of the tracheobronchial (TB) tree are lined with cartilaginous rings. Recent supercomputer simulations of in vivo conditions (cited herein), where cartilaginous ring morphologies were based upon fibre-optic bronchscope examinations, have clearly demonstrated their profound effects upon fluid dynamics. Since inhaled radionuclides of health effects concern such as randon progeny are entrained and transported by airstreams, their trajectories and deposition probabilities will be influenced by the character (i.e. laminar or turbulent) of air motion and its loca velocity profiles. A physiologically based analytical model of fluid dynamics is presented, focusing upon applications to particle diffusion within the TB tree. The new model is the first to describe particle motion while simulaneously simulating effects of wall irregularities, entrace conditions and tube curvatures. The results show that particle dose to the large bronchi may be underestimated by up to 35% if cartilaginous rings are not considered. The work has fundamental implications for modelling concepts and health effects applications. The findings indicate that caution must be exercised when extrapolating heat and/or mass transfer correlations derived from standard thermodynamic-hydrodynamic engineering problems to biological issues, and that human subject activity levels have pronounced effects on particle diffusion in the lung. For instance, the submicron particle deposition efficiency differences between a sedentary condition (i.e. office worker) and light activity (i.e. manual labourer) approach 40%. This study may explain the enhanced deposition by particle diffusion detected in replica case experiments and have salient implications for the clinically observed preferential distributions of bronchogenic carcinomas associated with inhaled radionuclides

249 Antigen inhalation induced systemic increases in histamine and chemotactic activity levels in subjects with rhinitis or asthma

249 Antigen inhalation induced systemic increases in histamine and chemotactic activity levels in subjects with rhinitis or asthma

Mathematical models for carboxyhemoglobin

This paper describes a non-linear model for blood COHb fraction as a function of a subject's activity level, individual physiological parameters, and individual time-variable exposure to carbon monoxide. The computer solution of the model fits data on smokers and non-smokers. The simpler models of Ott and Mage (1978) and Venkatram and Louch (1979) are shown to have the correct form in low-stress environments, but the simpler models do not allow assessment of health effects for sensitive or high-risk subpopulations. Their postulated constant time-scale of 2.49 h may lead to substantial underestimation of COHb buildup.