Scaling of smaller pyramidal neuron size and lower energy production in schizophrenia.

BACKGROUND: Dorsolateral prefrontal cortex (DLPFC) dysfunction in schizophrenia appears to reflect alterations in layer 3 pyramidal neurons (L3PNs), including smaller cell bodies and lower expression of mitochondrial energy production genes. However, prior somal size studies used biased strategies for identifying L3PNs, and somal size and levels of energy production markers have not been assessed in individual L3PNs. STUDY DESIGN: We combined fluorescent in situ hybridization (FISH) of vesicular glutamate transporter 1 (VGLUT1) mRNA and immunohistochemical-labeling of NeuN to determine if the cytoplasmic distribution of VGLUT1 mRNA permits the unbiased identification and somal size quantification of L3PNs. Dual-label FISH for VGLUT1 mRNA and cytochrome C oxidase subunit 4I1 (COX4I1) mRNA, a marker of energy production, was used to assess somal size and COX4I1 transcript levels in individual DLPFC L3PNs from schizophrenia (12 males; 2 females) and unaffected comparison (13 males; 1 female) subjects. STUDY RESULTS: Measures of L3PN somal size with NeuN immunohistochemistry or VGLUT1 mRNA provided nearly identical results (ICC = 0.96, p < 0.0001). Mean somal size of VGLUT1-identified L3PNs was 8.7% smaller (p = 0.004) and mean COX4I1 mRNA levels per L3PN were 16.7% lower (p = 0.01) in schizophrenia. These measures were correlated across individual L3PNs in both subject groups (rrm = 0.81-0.86). CONCLUSIONS: This preliminary study presents a novel method for combining unbiased neuronal identification with quantitative assessments of somal size and mRNA levels. We replicated findings of smaller somal size and lower COX4I1 mRNA levels in DLPFC L3PNs in schizophrenia. The normal scaling of COX4I1 mRNA levels with somal size in schizophrenia suggests that lower markers of energy production are secondary to L3PN morphological alterations in the illness.

Health care provider decision-making and the quality of maternity care: An analysis of postpartum care in Kenyan hospitals.

Evidence suggests that health care providers' non-adherence to clinical guidelines is widespread and contributes to poor patient outcomes across low- and middle-income countries. Through observations of maternity care in Kenya, we found limited adherence to guideline-recommended active monitoring of patients for signs of postpartum hemorrhage, the leading cause of maternal mortality, despite providers' having the necessary training and equipment. Using survey vignettes conducted with 144 maternity providers, we documented evidence consistent with subjective risk and perceived uncertainty driving providers' decisions to actively monitor patients. Motivated by these findings, we introduced a simple model of providers' decision-making about whether to monitor a patient, which may depend on their perceptions of risk, diagnostic uncertainty, and the value of new information. The model highlights key trade-offs between gathering diagnostic information through active monitoring versus waiting for signs and symptoms of hemorrhage to manifest. Our work provides a template for understanding provider decision-making and could inform interventions to encourage more proactive obstetric care.

Defining principles for a choice-based approach to HIV prevention.

The HIV prevention landscape is on the cusp of an unprecedented era of multiple biomedical prevention products available for distribution. Several HIV prevention options, such as oral pre-exposure prophylaxis (PrEP), dapivirine vaginal rings, and injectable cabotegravir for PrEP, are becoming more widely available. Although the future HIV prevention market promises to be rich in options, it would benefit from a core set of principles that uphold choice in all phases of product development, assessment, and introduction. These principles, as presented in this Viewpoint, show the applicability, opportunities, and challenges of choice in different contexts of HIV prevention and provide checkpoints of accountability. By committing to these principles, stakeholders at national and global levels can advance choice across all phases of the HIV prevention market, thereby ensuring that individuals can realise their right to choose when and how to prevent HIV in their own lives.

Quality of care for postpartum hemorrhage: A direct observation study in referral hospitals in Kenya.

Postpartum hemorrhage (PPH) is the leading cause of maternal mortality in Kenya. The aim of this study was to measure quality and timeliness of care for PPH in a sample of deliveries in referral hospitals in Kenya. We conducted direct observations of 907 vaginal deliveries in three Kenyan hospitals from October 2018 through February 2019, observing the care women received from admission for labor and delivery through hospital discharge. We identified cases of "suspected PPH", defined as cases in which providers indicated suspicion of and/or took an action to manage abnormal bleeding. We measured adherence to World Health Organization and Kenyan guidelines for PPH risk assessment, prevention, identification, and management and the timeliness of care in each domain. The rate of suspected PPH among the observed vaginal deliveries was 9% (95% Confidence Interval: 7% - 11%). Health care providers followed all guidelines for PPH risk assessment in 7% (5% - 10%) of observed deliveries and all guidelines for PPH prevention in 4% (3% - 6%) of observed deliveries. Lowest adherence was observed for taking vital signs and for timely administration of a prophylactic uterotonic. Providers did not follow guidelines for postpartum monitoring in any of the observed deliveries. When suspected PPH occurred, providers performed all recommended actions in 23% (6% - 40%) of cases. Many of the critical actions for suspected PPH were performed in a timely manner, but, in some cases, substantial delays were observed. In conclusion, we found significant gaps in the quality of risk assessment, prevention, identification, and management of PPH after vaginal deliveries in referral hospitals in Kenya. Efforts to reduce maternal morbidity and mortality from PPH should emphasize improvements in the quality of care, with a particular focus on postpartum monitoring and timely emergency response.

Health care providers' knowledge of clinical protocols for postpartum hemorrhage care in Kenya: a cross-sectional study.

BACKGROUND: Postpartum hemorrhage (PPH) remains the leading cause of maternal death worldwide despite its often-preventable nature. Understanding health care providers' knowledge of clinical protocols is imperative for improving quality of care and reducing mortality. This is especially pertinent in referral and teaching hospitals that train nursing and medical students and interns in addition to managing emergency and referral cases. METHODS: This study aimed to (1) measure health care providers' knowledge of clinical protocols for risk assessment, prevention, and management of PPH in 3 referral hospitals in Kenya and (2) examine factors associated with providers' knowledge. We developed a knowledge assessment tool based on past studies and clinical guidelines from the World Health Organization and the Kenyan Ministry of Health. We conducted in-person surveys with health care providers in three high-volume maternity facilities in Nairobi and western Kenya from October 2018-February 2019. We measured gaps in knowledge using a summative index and examined factors associated with knowledge (such as age, gender, qualification, experience, in-service training attendance, and a self-reported measure of peer-closeness) using linear regression. RESULTS: We interviewed 172 providers including consultants, medical officers, clinical officers, nurse-midwives, and students. Overall, knowledge was lowest for prevention-related protocols (an average of 0.71 out of 1.00; 95% CI 0.69-0.73) and highest for assessment-related protocols (0.81; 95% CI 0.79-0.83). Average knowledge scores did not differ significantly between qualified providers and students. Finally, we found that being a qualified nurse, having a specialization, being female, having a bachelor's degree and self-reported closer relationships with colleagues were statistically significantly associated with higher knowledge scores. CONCLUSION: We found gaps in knowledge of PPH care clinical protocols in Kenya. There is a clear need for innovations in clinical training to ensure that providers in teaching referral hospitals are prepared to prevent, assess, and manage PPH. It is possible that training interventions focused on learning by doing and teamwork may be beneficial.

Efficacy of an Individually Tailored, Internet-Mediated Physical Activity Intervention in Older Adults: A Randomized Controlled Trial.

OBJECTIVE: This study determined the effectiveness of an individually tailored, Internet-mediated physical activity (PA) intervention for increasing walking behavior in inactive older adults. METHOD: This 12-week randomly controlled intervention divided participants ( N = 170) into three groups: control (CON, n = 51), pedometer only (PED, n = 62), and an individually tailored, Internet-mediated pedometer (TI-PED, n = 57) group. The PED group was instructed to increase weekly step count by 10% until 10,000 steps per day was achieved. The TI-PED group was given the same goal and received tailored feedback via an online platform. Changes in average step count pre-to-post were assessed. RESULTS: Total retention rate at postintervention was 75.3%. PED ( p < .001) and TI-PED ( p < .001) increased step count pre-to-post, which was higher than the CON group at 12 weeks (PED, p < .001; TI-PED, p < .001). The TI-PED group had a higher step count at 12 weeks than the PED group ( p < .001). DISCUSSION: Individually tailored, Internet-mediated PA interventions are an effective way to significantly increase PA in older adults.

Isotemporal Substitution of Sedentary Behavior and Physical Activity on Function.

The amount of time spent in sedentary behaviors (SB) progressively increases with age, while reducing time spent in light-intensity physical activity (LPA) and moderate- to vigorous-intensity physical activity (MVPA). These trajectories in PA and SB are linked to accelerated reductions in physical functioning. PURPOSE: This study aimed to examine the association of substituting SB time with LPA and MVPA on physical function in older adults. METHODS: Ninety-one older adults (mean age, 70.7 ± 10.2 yr) wore a hip-mounted accelerometer to measure SB, LPA, and MVPA time. Measures of physical function included a 400-m walk test (400W), the usual gait speed (UGS), the five times sit-to-stand (5xSTS) test, and the short physical performance battery (SPPB). Isotemporal substitution regression modeling was performed to assess the relationship of replacing the amount of time spent in one activity for another. RESULTS: Replacing 30 min·d of SB with LPA was associated with a significant improvement in 400W (P = 0.0497), whereas MVPA resulted in a significant improvement (P < 0.01) in 400W, UGS, 5xSTS, and SPPB. Replacing 60 min·d of SB with 10 min·d of MVPA and 50 min·d of LPA was associated with significant improvements in the 400W, UGS, and 5xSTS (P < 0.05). Meanwhile, as little as 5 min·d of MVPA and 55 min·d of LPA were linked to a 78% increased odds of scoring with good function in the SPPB (P = 0.0247). CONCLUSION: Replacing SB with LPA was linked to a significant improvement in the 400W, but not the other brief functional measures. Mixed doses of LPA and MVPA may add flexibility to interventions targeting reductions of SB in older adults for clinically relevant improvements in physical function.

Individualized Estimation of Physical Activity in Older Adults with Type 2 Diabetes.

PURPOSE: Compare physical activity intensity in older adults with type 2 diabetes mellitus (T2DM) using individualized, relative cutpoints with standard, absolute cutpoints. METHODS: One hundred older adults with T2DM (68.9 ± 5.1 yr, 65% male, 32.7 ± 6.3 kg·m, 7.2% ± 1.1% glycosylated hemoglobin) completed a two-speed walking protocol (varying, walking between 1 and 2.5 mph), followed by a modified Bruce peak exercise test. Participants wore an accelerometer-based physical activity monitor at their waist, and oxygen consumption was measured. Afterward, participants wore the activity monitor for seven consecutive days. Linear equations for each individual were derived from the activity counts and energy expenditure measured during the walking protocol. Relative intensity cutpoints were calculated by using standard classifications of 44% oxygen consumption (V˙O2)peak to determine moderate and 59% V˙O2peak to determine vigorous intensity. Average time spent in intensity categories per day were calculated using relative and absolute (moderate, 2020 counts per minute; vigorous, 5999 counts per minute) cutpoints. t-Tests were run to compare estimated time spent in intensity category by cutpoint. RESULTS: Mean V˙O2peak was 17.9 ± 4.5 mL·kg·min and relative cutpoints were, on average, 1033.5 counts per minute (SD, 741.2 counts per minute) for moderate and 2211.7 counts per minute (SD, 1512.4) for vigorous activity. Using the relative cutpoints, participants accumulated an average of 157.2 min (SD, 73.7 min) of light, 33.3 min (SD, 35.6 min) of moderate, and 15.6 min (SD, 26.7 min) of vigorous activity per day. Use of the absolute cutpoint resulted in significantly different estimations based on intensity category: light, 200.7 min (SD, 74.7 min; P < 0.05); moderate, 7.1 min (SD, 9.2 min; P < 0.05); and vigorous, 0.006 min (SD, 0.04 min; P < 0.05) of activity per day. CONCLUSIONS: These results suggest utilization of absolute cutpoints may underestimate daily relative intensity levels of physical activity in older adults with T2DM. This misclassification may improperly inform dose-response relationships and population-based prevalence of physical activity in these and may extend to other clinically important populations.

A prospective examination of the impact of high levels of exercise training on sedentary behaviour.

The aim of this study is to determine changes in sedentary behaviour in response to extensive aerobic exercise training. Participants included adults who self-selected to run a marathon. Sedentary behaviour, total activity counts and physical activity (PA) intensity were assessed (Actigraph GT3X) for seven consecutive days during seven assessment periods (-3, -2, and -1 month prior to the marathon, within 2 weeks of the marathon, and +1, +2, and +3 months after the marathon). Models were fitted with multiple imputation data using the STATA mi module. Random intercept generalized least squares (GLS) regression models were used to determine change in sedentary behaviour with seven waves of repeated measures. RESULTS: Twenty-three individuals (mean ± Sx: 34.4 ± 2.1y, 23.0 ± 1.9% fat, 15 women, 8 men) completed the study. Marathon finishing times ranged from 185 to 344 minutes (253.2 ± 9.6 minutes). Total counts in the vertical axis were 1,729,414 lower one month after the race, compared with two months prior to the race (peak training). Furthermore, counts per minute decreased by 252.7 counts·minute-1 during that same time period. Daily sedentary behaviour did not change over the seven assessment periods, after accounting for age, gender, per cent body fat, wear time, marathon finishing time, and previous marathon experience. This prospective study supports the notion that PA and sedentary behaviours are distinct, showing that sedentary behaviour was not impacted by high levels of aerobic training.

A positive association between active lifestyle and hemispheric lateralization for motor control and learning in older adults.

Physical activity (PA) is well known to have general health benefits for older adults, but it is unclear whether it can also positively affect brain function involved in motor control and learning. We have previously shown that interlimb transfer of visuomotor adaptation occurs asymmetrically in young adults, while that occurs symmetrically in older adults, which suggests that the lateralized function of each hemisphere during motor tasks is diminished with aging. Here, we investigated the association between the level of PA and hemispheric motor lateralization by comparing the pattern of interlimb transfer following visuomotor adaptation between physically active and inactive older adults. Subjects were divided into two groups based on their PA level (active, inactive). They were further divided into two groups, such that a half of the subjects in each group adapted to a 30° rotation during targeted reaching movements with the left arm first, then with the right arm; and the other half with the right arm first, then with the left arm. Results indicated asymmetrical transfer (from left to right only) in the active subjects, whereas symmetrical transfer (from left to right, and vice versa) was observed in the inactive subjects. These findings suggest that older adults who maintain active lifestyle have a central nervous system that is more intact in terms of its lateralized motor function as compared with those who are inactive.

Exploring the prevalence of disrespect and abuse during childbirth in Kenya.

BACKGROUND: Poor quality of care including fear of disrespect and abuse (D&A) perpetuated by health workers influences women's decisions to seek maternity care. Key manifestations of D&A include: physical abuse, non-consented care, non-confidential care, non-dignified care, discrimination, abandonment, and detention in facilities. This paper describes manifestations of D&A experienced in Kenya and measures their prevalence. METHODS: This paper is based on baseline data collected during a before-and-after study designed to measure the effect of a package of interventions to reduce the prevalence of D&A experienced by women during labor and delivery in thirteen Kenyan health facilities. Data were collected through an exit survey of 641 women discharged from postnatal wards. We present percentages of D&A manifestations and odds ratios of its relationship with demographic characteristics using a multivariate fixed effects logistic regression model. RESULTS: Twenty percent of women reported any form of D&A. Manifestations of D&A includes: non-confidential care (8.5%), non-dignified care (18%), neglect or abandonment (14.3%), Non-consensual care (4.3%) physical abuse (4.2%) and, detainment for non-payment of fees (8.1). Women aged 20-29 years were less likely to experience non-confidential care compared to those under 19; OR: [0.6 95% CI (0.36, 0.90); p=0.017]. Clients with no companion during delivery were less likely to experience inappropriate demands for payment; OR: [0.49 (0.26, 0.95); p=0.037]; while women with higher parities were three times more likely to be detained for lack of payment and five times more likely to be bribed compared to those experiencing there first birth. CONCLUSION: One out of five women experienced feeling humiliated during labor and delivery. Six categories of D&A during childbirth in Kenya were reported. Understanding the prevalence of D&A is critical in developing interventions at national, health facility and community levels to address the factors and drivers that influence D&A in facilities and to encourage clients' future facility utilization.

Relative importance of step count, intensity, and duration on physical activity's impact on vascular structure and function in previously sedentary older adults.

BACKGROUND: Age-related endothelial dysfunction and vascular stiffening are associated with increased cardiovascular (CV) risk. Many groups have encouraged goals of ≥10 000 steps/day or ≥30 min/day of moderate intensity physical activity (MPA) to reduce age-related CV risk. The impact of MPA on the vasculature of older adults remains unclear. METHODS AND RESULTS: We randomized 114 sedentary older adults ages ≥50 to 12 weeks of either no intervention (group 1), a pedometer-only intervention (group 2), or a pedometer with an interactive website employing strategies to increase the adoption of habitual physical activity (PA, group 3). Endothelial function by brachial flow-mediated dilation (FMD%), vascular stiffness by tonometry, step-count by pedometer, and PA intensity/distribution by accelerometer were measured. Step-count increased in groups 2 (5136±1554 to 9596±3907, P<0.001) and 3 (5474±1512 to 8167±3111, P<0.001) but not in group 1 (4931±1667 to 5410±2410). Both groups 2 and 3 increased MPA ≥30 min/day. Only group 3 increased MPA in continuous bouts of ≥10 minutes (P<0.001) and improved FMD% (P=0.001). Neither achievement of ≥10 000 steps/day nor ≥30 min/day of MPA resulted in improved FMD%. However, achieving ≥20 min/day in MPA bouts resulted in improved FMD%. No changes in vascular stiffness were observed. CONCLUSIONS: MPA reverses age-related endothelial dysfunction, but may require MPA to be performed in bouts of ≥10 minutes duration for ≥20 min/day to be effective. Commonly encouraged PA goals do not guarantee improved endothelial function and may not be as effective in reducing CV risk. CLINICAL TRIAL REGISTRATION URL: Clinicaltrials.gov. UNIQUE IDENTIFIER: NCT-01212978.

Accuracy of uploadable pedometers in laboratory, overground, and free-living conditions in young and older adults.

PURPOSE: The purpose of this study was to examine the accuracy of uploadable pedometers to accurately count steps during treadmill (TM) and overground (OG) walking, and during a 24 hour monitoring period (24 hr) under free living conditions in young and older adults. METHODS: One hundred and two participants (n=53 aged 20-49 yrs; n=49 aged 50-80 yrs) completed a TM protocol (53.6, 67.0, 80.4, 93.8, and 107.2 m/min, five minutes for each speed) and an OG walking protocol (self-determined "< normal", "normal", and "> normal" walking speeds) while wearing two waist-mounted uploadable pedometers (Omron HJ-720ITC [OM] and Kenz Lifecorder EX [LC]). Actual steps were manually tallied by a researcher. During the 24 hr period, participants wore a New Lifestyles-1000 (NL) pedometer (standard of care) attached to a belt at waist level over the midline of the left thigh, in addition to the LC on the belt over the midline of the right thigh. The following day, the same procedure was conducted, replacing the LC with the OM. One-sample t-tests were performed to compare measured and manually tallied steps during the TM and OG protocols, and between steps quantified by the NL with that of the OM and LC during the 24 hr period. Mean error step scores (MES, criterion - device) and 95% Limits of Agreement (LoA) were calculated. RESULTS: There were no significant differences between the OM and tallied steps for any of the TM speeds for either the young or older adult groups. The LC significantly underestimated steps for the young adult group during the 53.6 m/min TM speed (MES 31.4 [14.5, 48.3]) and during the OG < normal walking speed (MES 12.0 [0.9, 23.1] (p<0.01 for both age groups). The LC also significantly underestimated steps for the older adult group during the TM speeds of 53.6 m/min (MES 64.5 [45.6, 83.4]), 67.0 m/min (MES 15.1 [6.1, 24.0]), and 80.4 m/min (MES 3.2 [0.6, 5.9]) (p<0.01 for all speeds), in addition to the OG < normal walking speed (MES 14.7 [-13.3, 42.6] (p<0.01). The OM reported significantly lower steps during the 24 hr period for the young adult group by 949.1 steps (t=6.111, p<0.025) and for the older adult group by 612.9 steps (t=2.397, p<0.025). CONCLUSION: Both the OM and LC pedometers were more accurate as TM and OG walking speed increased. The OM significantly underestimated steps during the 24 hr compared with a standard of care evaluation. Overall, both uploadable pedometers appear acceptable to use in young or old age groups to measure walking behavior.

Comparison of the IPAQ-Short Form and accelerometry predictions of physical activity in older adults.

Older adult physical activity (PA) levels obtained from the International Physical Activity Questionnaire-Short Form (IPAQ) and accelerometry (ACC) were compared. Mean difference scores between accumulated or bout ACC PA and the IPAQ were computed. Spearman rank-order correlations were used to assess relations between time spent in PA measured from ACC and self-reported form of the IPAQ, and percentage agreement across measures was used to classify meeting or not meeting PA recommendations. The IPAQ significantly underestimated sitting and overestimated time spent in almost all PA intensities. Group associations across measures revealed significant relations in walking, total PA, and sitting for the whole group (r = .29-.36, p < .05). Significant relationships between bout ACC and IPAQ walking (r = .28-.39, p < .05) were found. There was 40-46% agreement between measures for meeting PA recommendations. The IPAQ appears not to be a good indicator of individual older adult PA behavior but is better suited for larger population-based samples.

Prediction of body fat in older adults by time spent in sedentary behavior.

The purpose of the study was to determine the relationship between sedentary behavior (SB), physical activity (PA), and body fat (total, abdominal) or body size (body-mass index [BMI], waist circumference [WC]) in community-dwelling adults 50 yr old and over. This study included 232 ambulatory adults (50-87 yr, 37.4% ± 9.6% body fat [BF]). Average daily time spent in SB (<100 counts/min) and light (100-759 counts/min), lifestyle-moderate (760-1,951 counts/min), walking-moderate (1,952-5,724 cts/min), and vigorous-intensity (≥ 5,725 counts/min) PA were determined by accelerometer and corrected for wear time. BF was measured with dual-energy X-ray absorptiometry. SB was positively related to measures of BF. Measures of SB, PA, and gender accounted for 55.6% of the variance in total BF, 32.4% of the variance in abdominal fat, and 28.0% of the variance in WC. SB, PA, and age accounted for 27.1% of the variance in BMI. Time spent in SB should be considered when designing obesity interventions for adults 50 yr old and over.

A pilot randomized controlled trial evaluating motivationally matched pedometer feedback to increase physical activity behavior in older adults.

BACKGROUND: Increasing physical activity (PA) levels in older adults represents an important public health challenge. The purpose of this study was to evaluate the feasibility of combining individualized motivational messaging with pedometer walking step targets to increase PA in previously inactive and insufficiently active older adults. METHODS: In this 12-week intervention study older adults were randomized to 1 of 4 study arms: Group 1--control; Group 2--pedometer 10,000 step goal; Group 3--pedometer step goal plus individualized motivational feedback; or Group 4--everything in Group 3 augmented with biweekly telephone feedback. RESULTS: 81 participants were randomized into the study, 61 participants completed the study with an average age of 63.8 ± 6.0 years. Group 1 did not differ in accumulated steps/day following the 12-week intervention compared with participants in Group 2. Participants in Groups 3 and 4 took on average 2159 (P < .001) and 2488 (P < .001) more steps/day, respectively, than those in Group 1 after the 12-week intervention. CONCLUSION: In this 12-week pilot randomized control trial, a pedometer feedback intervention partnered with individually matched motivational messaging was an effective intervention strategy to significantly increase PA behavior in previously inactive and insufficiently active older adults.

A Pilot Randomized Controlled Trial Evaluating Motivationally Matched Pedometer Feedback to Increase Physical Activity Behavior in Older Adults.

BACKGROUND: Increasing physical activity (PA) levels in older adults represents an important public health challenge. The purpose of this study was to evaluate the feasibility of combining individualized motivational messaging with pedometer walking step targets to increase PA in previously inactive and insufficiently active older adults. METHODS: In this 12-week intervention study older adults were randomized to 1 of 4 study arms: Group 1-control; Group 2-pedometer 10,000 step goal; Group 3-pedometer step goal plus individualized motivational feedback; or Group 4-everything in Group 3 augmented with biweekly telephone feedback. RESULTS: 81 participants were randomized into the study, 61 participants completed the study with an average age of 63.8 ± 6.0 years. Group 1 did not differ in accumulated steps/day following the 12-week intervention compared with participants in Group 2. Participants in Groups 3 and 4 took on average 2159 (P < .001) and 2488 (P < .001) more steps/day, respectively, than those in Group 1 after the 12-week intervention. CONCLUSION: In this 12-week pilot randomized control trial, a pedometer feedback intervention partnered with individually matched motivational messaging was an effective intervention strategy to significantly increase PA behavior in previously inactive and insufficiently active older adults.

Estimating absolute and relative physical activity intensity across age via accelerometry in adults.

This study examined the predictive validity of accelerometers (ACC) to estimate physical activity intensity (PAI) across age and differences in intensity predictions when expressed in relative and absolute PAI terms. Ninety adults categorized into 3 age groups (20-29, 40-49, and 60-69 yr) completed a treadmill calibration study with simultaneous ACC (7164 Actigraph) and oxygen-consumption assessment. Results revealed strong linear relations between ACC output and measured PAI (R2 = .62-.89) across age and similar ACC cut-point ranges across age delineating absolute PAI ranges compared with previous findings. Comparing measured metabolic equivalents (METs) with estimated METs derived from previously published regression equations revealed that age did not affect predictive validity of ACC estimates of absolute PAI. Comparing ACC output expressed in relative vs. absolute terms across age revealed substantial differences in PAI ACC count ranges. Further work is warranted to increase the applicability ofACC use relative to PAI differences associated with physiological changes with age.

Validity of Physical Activity Monitors in Assessing Energy Expenditure in Normal, Overweight, and Obese Adults.

A comparison of the validity of downloadable motion sensors, which use either a glass-enclosed magnetic reed proximity switch technology, a piezo-electric sensor accelerometer with a horizontal beam technology, or an internal pendulum based mechanism to determine energy expenditure (EE), across different body sizes does not exist. Therefore, the purpose of this study was to determine the validity of three different downloadable motion sensors to estimate EE during walking activity in normal weight, overweight and obese volunteers. Forty-eight participants completed this study. Each participant had their body height and mass measured and completed a treadmill walking protocol. Body mass index (BMI) was calculated. The treadmill walking protocol included six 5-minute stages starting at 1.5 mph and increasing by 0.5 mph, up to 4.0 mph while grade was constant at 0% for the duration of the test. The Kenz Life-Corder EX (LC), the Omron HJ-700IT (OM) and the Sportbrain iStep X1 (SB) were worn during the treadmill walking protocol. Heart rate, oxygen consumption, carbon dioxide production and EE estimated from the motion sensors were monitored throughout the walking protocol. Results showed the OM overestimated net EE in normal, overweight and obese participants. The LC underestimated gross EE in all groups. The SB overestimated net EE in normal BMI participants, was not significantly different from the criterion measure of net EE in overweight participants and underestimated net EE in obese individuals. This study demonstrates that these devices do not offer the accuracy needed to provide precise feedback on EE for individuals with varying BMI levels.

The impact of body-mass index and steps per day on blood pressure and fasting glucose in older adults.

The purpose of this study was to investigate the combined impact of obesity and physical activity (PA) on the health of older adults. Pedometer-determined steps/d, body-mass index (BMI), resting blood pressure, and fasting glucose (FG) were assessed in 137 older adults (69.0 +/- 8.9 yr). The active group (>4,227 steps/d) had lower systolic blood pressure (SBP; p = .001), diastolic blood pressure (DBP; p = .028), and FG (p < .001) than the inactive group (< or = 4,227 steps/d). The normal-BMI group (18.5-24.9 kg/m2) had lower SBP (p < .001) and DBP (p = .01) than the obese group (> or =30 kg/m2). There were no differences in SBP (p = .963) or DBP (p = 1.0) between active obese and inactive normal-BMI groups. The active obese group, however, had a more favorable FG than the inactive normal-BMI group (chi 2 = 18.9, df = 3, p = .001). Efforts to increase PA of older adults should receive the same priority as reducing obesity to improve BP and FG levels.