Nora E. Miller

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.

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

PurposeThe 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.MethodsOne 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.ResultsThere 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).ConclusionBoth 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.

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.

Glucose Control and Walking in a Multiethnic Sample of Older Adults

Background: Although walking is the most commonly reported physical activity by older adults, there is a paucity of data determining the relationship between objectively determined walking behavior and glucose dynamics in older adults. Objective: This study was designed to investigate the relationship between objectively determined walking behavior and glucose control in a multiethnic sample of older adults. Methods: Data were collected on 142 older adults (age 72.1 ± 9.2 years; body mass index (BMI) 29.4 ± 6.3; 37 males, 105 females). Anthropometric measures, fasting plasma glucose (FG), and glycosylated hemoglobin A1c (HbA1c) were assessed; race/ethnicity was self-reported. The study participants wore a pedometer for 7 consecutive days. Results: The average number of steps/day reported by the entire group was 3,939 ± 232. White participants (n = 48) were older (p = 0.019), taller (p = 0.002), had lower waist circumference (WC) (p = 0.021), HbA1c (p = 0.001) and FG (p = 0.007), and did not differ in average steps/day (p = 0.162) or BMI (p = 0.280) as compared with nonwhite participants (n = 94). Individuals with HbA1c values <7% and those with FG <100 mg/dl walked about 1,343 more steps/day than those with unfavorable HbA1c and/or FG values. Age, race/ethnicity, WC, BMI, log base 10 of steps/days, and type 1 and 2 diabetes medications accounted for 37.5% of the variance in inverse HbA1c (p < 0.001), with significant or near significant individual model contributions consisting of WC (beta = –0.316, B = –0.001, SE = 0.000, p = 0.047), BMI (beta = 0.310, B = 0.001, SE = 0.001, p = 0.050), diabetic medication (beta = –0.473, B = –0.035, SE = 0.006, p < 0.001), and log base 10 of steps/day (beta = 0.198, B = 0.019, SE = 0.010, p = 0.056). Interpretations of transformed data illustrate that greater WC and being on diabetic medications are associated with higher HbA1c levels. Further, there is a trend to suggest that fewer accumulated steps/day and lower BMI are associated with higher HbA1c concentrations. Conclusions: This study demonstrated that objectively determined walking behavior and indicators of obesity were modest predictors of chronic glucose control, after accounting for glucose-altering medications, in this multicultural sample of older adults. Further, when comparing individuals with good glucose control to those with less favorable glucose control, walking an additional 0.5–0.75 miles was associated with better glucose control.

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.

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.

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

Abstract 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.

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−2, 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−1·min−1 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.

Validity of Accelerometer Methods to Estimate Activity Energy Cost in Adults With and Without Functional Limitations: 2900 June 3 2: 30 PM - 2: 45 PM.

2898 June 3 2:00 PM 2:15 PM Comparison Of Outcomes Between Raw Acceleration And Counts-based Methods For Processing Wrist-worn Accelerometers: The Flashe Study Youngwon Kim, Paul Hibbing, Laura D. Ellingson, Pedro F. Saint-Maurice, Erin Hennessy, James McClain, Gregory J. Welk, FACSM. University of Cambridge, Cambridge, United Kingdom. Iowa State University, Ames, IA. Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD. National Cancer Institute, Bethesda, MD. (Sponsor: Gregory Welk, FACSM) Email: youngwon.kim@mrc-epid.cam.ac.uk