Seasonal Variation of Physical Activity in Community-Living vs. Residential-Dwelling Older Adults

Background and Purpose: Although physical activity (PA) is important for all ages including older adults, participation may be influenced by weather variation and access to programming. Our primary aim was determine if PA participation is influenced by season and place of residence. A secondary aim was to compare objective and subjective measure of PA participation. Methods: Participants included older individuals (age>65) living in a residential retirement community (RR) with access to an on-site fitness facility (n=7) and additional volunteers (n=9) who lived at home and traveled to exercise at a nonresidential community (NR) activities center Accelerometers were used to measure daily PA during the summer and again during the winter. Results: PA for the NR group was higher in the summer (268.4�73.7 min vs. RR=186.8�68.0, p=0.039), but not in the winter (NR=261.8�92.6 min, RR=182.0�72.5, p=0.082). No within-group change in PA was noted from summer to winter for either group (p>0.05). The correlation between subjective and objective measures of PA was low (r=.262). Conclusion: Access to appropriate facilities and programming serves to help older individuals maintain PA levels despite seasonal weather variations. The low correlation between objective and subjective measures suggest a need to re-evaluate methods of tracking PA participation by older adults

Syndepositional diagenetic control of molybdenum isotope variations in carbonate sediments from the Bahamas

© 2016 Elsevier B.V. Molybdenum (Mo) isotope variations recorded in black shales provide important constraints on marine paleoredox conditions. However, suitable shales are not ubiquitous in the geologic record. Moreover, reliable reconstruction of Mo isotope records from shales requires deposition from a water column containing very high concentrations of sulfide-a condition which is both rare and difficult to verify with certainty when examining preserved sediments. The utility of Mo isotopic records could be improved if reconstructions were possible using alternative lithologies, such as marine carbonates, which are more abundant in the geologic record.Here, we focus on the role of early diagenesis in determining the Mo isotopic composition preserved in shallow-water carbonate sediments from four push cores collected in different shallow-water depositional environments in the Bahamas. In contrast with carbonate primary precipitates, which generally contain 10 ppm Mo). The extent of this authigenic enrichment appears to be driven by high concentrations of hydrogen sulfide in the porewaters. In cores with the least authigenic Mo enrichment and lowest pore water sulfide, Mo isotopes are ~1-1.2‰ lighter than seawater, while cores with greater Mo enrichments and higher pore water sulfide approach seawater Mo isotope values (2.2-2.5‰), even under oxic bottom water conditions. However, the sensitivity of bulk carbonate δ98Mo to syndepositional diagenetic conditions potentially complicates interpretation of a carbonate Mo isotope paleoredox proxy. Robust reconstruction of seawater Mo isotopic composition from carbonates will thus require the ability to place constraints on early diagenetic conditions of pore waters at the time of deposition. We show that in order to record seawater Mo isotope values, carbonate pore waters must contain 50-100 μM H2Saq, which is achieved only in organic- and sulfide-rich carbonate sediments

Biological effects on uranium isotope fractionation (\u3csup\u3e238\u3c/sup\u3eU/\u3csup\u3e235\u3c/sup\u3eU) in primary biogenic carbonates

© 2018 Elsevier Ltd Determining whether U isotopes are fractionated during incorporation into biogenic carbonates could help to refine the application of 238U/235U in CaCO3 as a robust paleoredox proxy. Recent laboratory experiments have demonstrated that heavy uranium (U) isotopes were preferentially incorporated into abiotic aragonite, with an isotope fractionation of ∼0.10‰ (238U/235U). In contrast, no detectable U isotope fractionation has been observed in most natural primary biogenic carbonates, but the typical measurement precision of these studies was ±0.10‰ and so could not resolve a fractionation of the magnitude observed in the laboratory. To resolve this issue, we have developed a high precision 238U/235U method (±0.02‰ 2 SD) and utilized it to investigate 238U/235U in primary biogenic carbonates including scleractinian corals, calcareous green and red algae, echinoderms, and mollusks, as well as ooids from the Bahamas, Gulf of California, and French Polynesia. Our results reveal that many primary biogenic carbonates indeed fractionate U isotopes during U incorporation, and that this fractionation is in the same direction as observed in abiotic CaCO3 coprecipitation experiments. However, the magnitude of isotope fractionation in biogenic carbonates is often smaller than that predicted by abiotic CaCO3 coprecipitation experiments (0.00–0.09‰ vs. 0.11 ± 0.02‰), suggesting that one or more processes suppress U isotope fractionation during U incorporation into biogenic carbonates. We propose that closed-system behavior due to the isolation of the local calcificiation sites from ambient seawater, and/or kinetic/disequilibrium isotope fractionation caused by carbonate growth kinetics, explains this observation. Our results indicate that U isotope fractionation between biogenic carbonates and seawater might help to constrain U partition coefficients, carbonate growth rates, or seawater chemistry during coprecipitation

Uranium isotope fractionation during coprecipitation with aragonite and calcite

© 2016 Elsevier Ltd. Natural variations in 238U/235U of marine calcium carbonates might provide a useful way of constraining redox conditions of ancient environments. In order to evaluate the reliability of this proxy, we conducted aragonite and calcite coprecipitation experiments at pH ~7.5 and ~8.5 to study possible U isotope fractionation during incorporation into these minerals.Small but significant U isotope fractionation was observed in aragonite experiments at pH ~8.5, with heavier U isotopes preferentially enriched in the solid phase. 238U/235U of dissolved U in these experiments can be fit by Rayleigh fractionation curves with fractionation factors of 1.00007 + 0.00002/-0.00003, 1.00005 ± 0.00001, and 1.00003 ± 0.00001. In contrast, no resolvable U isotope fractionation was observed in an aragonite experiment at pH ~7.5 or in calcite experiments at either pH. Equilibrium isotope fractionation among different aqueous U species is the most likely explanation for these findings. Certain charged U species are preferentially incorporated into calcium carbonate relative to the uncharged U species Ca2UO2(CO3)3(aq), which we hypothesize has a lighter equilibrium U isotope composition than most of the charged species. According to this hypothesis, the magnitude of U isotope fractionation should scale with the fraction of dissolved U that is present as Ca2UO2(CO3)3(aq). This expectation is confirmed by equilibrium speciation modeling of our experiments. Theoretical calculation of the U isotope fractionation factors between different U species could further test this hypothesis and our proposed fractionation mechanism.These findings suggest that U isotope variations in ancient carbonates could be controlled by changes in the aqueous speciation of seawater U, particularly changes in seawater pH, PCO2, Ca2+, or Mg2+ concentrations. In general, these effects are likely to be small (\u3c0.13‰), but are nevertheless potentially significant because of the small natural range of variation of 238U/235U

Linear/Nonlinear Relations of Activity and Fitness with Children’s Academic Achievement

This is an an accepted manuscript and not the final published version.ABSTRACT: A growing research base suggests the benefits of physical activity (PA) and aerobic fitness for children extend beyond overall health/well-being to include academic achievement (AA). The majority of research studies on relations of PA and fitness with AA have utilized linear-only analytic approaches, thereby precluding the possibility that PA and fitness could have a differing impact on AA for those more/less active or fit. OBJECTIVE: Evaluate both linear and non-linear associations of PA and aerobic fitness with children’s AA among a sample of 687 2nd and 3rd grade students from 17 Midwest schools. STUDY DESIGN: Using baseline data (fall 2011) from a larger 3-year intervention trial, multi-level regression analyses examined the linear and non-linear associations of AA with PA and with PACER laps (i.e., aerobic fitness), controlling for relevant covariates. RESULTS: Fitness, but not PA, had a significant quadratic association with both spelling and math achievement. Results indicate that 22–28 laps on the PACER was the point at which the associated increase in achievement per lap plateaued for spelling and math. CONCLUSIONS: Increasing fitness could potentially have the greatest impact on children’s AA for those below the 50th fitness percentile on the PACER

Oxygen Cost of Performing Selected Adult and Child Care Activities

International Journal of Exercise Science 6(1) : 11-19, 2013. Little is known about the oxygen cost of caring for infants and older adults. Many people perform these activities so it is useful to know the energy cost and if the activities are of sufficient intensity to contribute to meeting physical activity recommendations. The purpose of this study was to assess the oxygen cost of four care-related activities in the Compendium of Physical Activities. Nineteen participants (n = 10 women, n = 9 men; Age = 36.4 ± 13.6 y; % Fat = 34.1 ± 10.5; BMI = 28.1 ± 4.5 kg/m2) performed four activities: 1) pushing an infant in a stroller, 2) pushing an adult in a wheelchair, 3) carrying an infant, and 4) bathing and dressing an infant. The oxygen cost was assessed using a portable metabolic unit. Activities were performed in random order for 8 minutes. The oxygen cost and heart rates, respectively, for healthy adults during care related activities were 3.09 METs and 90 ± 8 beats per minute (bpm) for pushing an infant in a stroller, 3.69 METs and 97 ± 9 bpm for pushing an adult in a wheelchair, 2.37 METs and 85 ± 9 bpm for carrying an infant, and 2.00 METs and 87 ± 9 bpm for bathing and dressing an infant. Carrying an infant and bathing an infant are light-intensity physical activities and pushing a wheelchair or a stroller are moderate intensity activities. The latter activities are of sufficient intensity to meet health-related physical activity recommendations

Patterns of weight change in a commercial weight loss program

Objectives: In this study, we examined compliance and progress factors associated with weight loss and maintenance, individual patterns of weight trends following weight loss, and impact of early weight loss on longer-term weight change. Methods: We conducted secondary analysis of pre-post data. Participants were 8769 persons (mean age = 47.63 ± 13.78 years; 77.74% women; mean weight = 97.20 ± 22.82 kilograms; BMI = 34.09 ± 6.84) in a commercial weight management program. We carried out multiple regression analyses on weight change and percentage, and used ANOVA and the Pearson chi-square test to examine participant characteristics, weight change patterns, and early weight loss success. Results: Participants were active in the program for 222 ± 158 days, completed 15 ± 13 appointments, achieving -8.53 ± 7.87 kilograms lost (-8.61% ± 7.64%). Greater weight loss was associated with appointment frequency (β = -0.46) and total spending (β = -2.89) (p \u3c .01). We identified 5 weight change patterns (F = 37.56, p \u3c .001) (total weight loss for each group was: Stable = -10.4% [N=2036]; Minimal Regain = -10.5% [N=3766]; Modest Regain = -8.8% [N=1476]; Large Regain = -7.3% [N=753]; No Loss/Gain = +3.7% [N=737]; all p \u3c .05). Over 5000 participants achieved early weight loss (losing \u3e 5%) within the first 2 months resulting in significantly greater final weight loss (-8.43% to -14.56% vs -1.18% to -3.15%). Conclusions: We identified several weight patterns; increased health coaching attendance was associated with greater weight loss

Energy Costs of Chair Sitting and Standing Video Exercises in Chinese Older Adults, Ages 60 to 89 years

International Journal of Exercise Science 16(7): 814-827, 2023. Home-based video exercise interventions improve older adults’ physiological performance and functional capacity. Little is known about the energy costs of video exercises in older adults. The Compendium of Physical Activities (PAs) has few items with PA metabolic equivalents (METs) in older adults. This study measured the energy costs of four chair and two standing exercises (sitting Tai Chi, Yoga, mobility ball, aerobics: standing, slow aerobics, and fast aerobics). Fifteen females and 14 males, 62-87 years (M ± SD, 73 ± 7.7 years), were categorized into three age groups (60-69, 70-79, 80-89). Oxygen uptake (VO2, ml.min-1.kg-1) and heart rate (HR, b.min-1) were measured by indirect calorimetry and heart rate monitor. MET values were calculated as standard- (activity VO2/3.5), rounded- (significant digit rounded to 0, 3, 5, 8), and corrected METs (individual resting metabolism). Results showed chair Yoga, Tai Chi, and mobility ball ranged from 2.0 to 2.8 rounded METs (light intensity). Chair- and standing aerobics ranged from 3.0 to 4.3 rounded METs (moderate intensity). Averaged HR ranged from 91.9 ± 12.7 b.min-1 to 115.4 ± 19.1 b.min-1 for all PAs. Corrected METs were higher than standard METs (P \u3c .05). Standard METs were similar between age groups (P \u3e .05). In conclusion, this study is unique as it measures the energy costs of sitting and standing video exercises that can be performed by older adults at home or in an exercise facility. Knowing the energy costs of PAs for older adults can provide exercises interventions to prevent sedentary lifestyles

The Construct and Predictive Validity of Instruments Measuring the Psychosocial Correlates of Television Viewing

Background: Many studies have examined the consequences of prolonged television viewing, but few studies have examined the psychological states that contribute to this behavior. In this study, we evaluated the construct and predictive validity of psychosocial correlates of television viewing in a population of African American (AA) breast cancer survivors (BCS). Methods: AA BCS (N = 342, Mean age = 54 years) completed measures of decisional balance, self-efficacy, family support, and time spent watching television online. Exploratory structural equation modeling (ESEM) was used to examine the construct and predictive validity as well as the differential item functioning of the instruments among population subgroups. Results: The construct validity of the measures was supported among subgroups. The scales were measuring the construct similarly among the education and body size groups, but not among age groups. Subsequent analysis indicated that pros (β = -0.19, P \u3c 0.05), cons (β = 0.18, P \u3c 0.05), and self-efficacy (β = -0.16, P \u3c 0.05) were significantly associated with time spent watching television. Conclusions: Minor modifications may be needed to support the validity and reliability of the decisional balance and self-efficacy subscales among older survivors. More studies are needed to modify these measures to establish sufficient levels of construct and predictive validity in this population

Indirect and direct relations between aerobic fitness, physical activity, and academic achievement in elementary school students

BACKGROUND: There is evidence to suggest that increasing physical activity (PA) improves academic achievement (AA) in children and that aerobic fitness is associated with both cognitive function and AA. However, it is not known how these variables are interrelated and analyses with adequate control for socioeconomic variables are needed. It was hypothesized that PA would not directly affect AA but would have an indirect effect on AA through its effect on aerobic fitness. The purpose of this study was to test this hypothesized mediation using path analysis. METHODS: Cross-sectional data including AA, aerobic fitness, and daily PA assessed through accelerometry were collected from a large sample (N = 687) of 2nd and 3rd grade students. Demographic data were assessed via parent self-report. RESULTS: A total of 401 students wore the accelerometer for at least 10 hours on 3 days or more and were included in the final path analysis to evaluate potential relations among PA (predictor), aerobic fitness (mediator), and WIAT-III subtest standard scores (outcomes; i.e., reading, spelling, and mathematics). Findings showed a direct effect of PA on aerobic fitness (b = 0.009, p < 0.001) and an indirect effect (mediation) of PA via fitness on math achievement (b = 0.003, p < 0.01) after controlling for student’s grade, gender, body mass index, mother’s education level, and household income, as well as intraclass correlations among classes and schools. Neither PA nor aerobic fitness were correlated with WIAT-III reading or spelling scores. CONCLUSIONS: Mediation analysis indicated that PA exerted an influence on math achievement through its effects on aerobic fitness but was not associated with reading or spelling achievement scores