Ratings of Perceived Exertion During Walking: Predicting Major Mobility Disability and Effect of Structured Physical Activity in Mobility-Limited Older Adults.

BACKGROUND: This study evaluated the association between ratings of perceived exertion (RPE) of walking and major mobility disability (MMD), as well as their transitions in response to a physical activity (PA) compared to a health education (HE) program. METHODS: Older adults (n = 1633) who were at risk for mobility impairment were randomized to structured PA or HE programs. During a 400 m walk, participants rated exertion as "light" or "hard." An MMD event was defined as the inability to walk 400 m. MMD events and RPE values were assessed every 6 months for an average of 2.6 years. RESULTS: Participants rating their exertion as "hard" had a nearly threefold higher risk of MMD compared with those rating their exertion as "light" (HR: 2.61, 95% CI: 2.19-3.11). The association was held after adjusting for disease conditions, depression, cognitive function, and walking speed (HR: 2.24, 95% CI: 1.87-2.69). The PA group was 25% more likely to transition from "light" to "hard" RPE than the HE group (HR: 1.25, 95% CI: 1.05-1.49). Additionally, the PA group was 27% (HR: 0.73, 95% CI: 0.55 - 0.97) less likely to transition from a "hard" RPE to inability to walk 400 m and was more likely to recover their ability to walk 400 m by transitioning to a "hard" RPE (HR: 2.10, 95% CI: 1.39-3.17) than the HE group. CONCLUSIONS: Older adults rating "hard" effort during a standardized walk test were at increased risk of subsequent MMD. A structured PA program enabled walking recovery, but was more likely to increase transition from "light" to "hard" effort, which may reflect the greater capacity to perform the test.

Effects of a Hypocaloric, Nutritionally Complete, Higher Protein Meal Plan on Regional Body Fat and Cardiometabolic Biomarkers in Older Adults with Obesity.

BACKGROUND: Whether improvements in cardiometabolic health following weight loss (WL) are associated with changes in regional body fat distribution (gluteal vs. -android) is not well documented. METHODS: Older (age: 70 ± 4 years; mean ± SD) adults with obesity were randomized to a 6-month WL program (WL; n = 47), accomplished using a hypocaloric, nutritionally complete, higher protein -(targeting ≥1.0 g/kg/day) meal plan, or a weight stability (WS; n = 49) program. Android, gynoid, visceral, and subcutaneous abdominal fat masses (via dual energy X-ray absorptiometry ) and fasting glucose and lipid profiles were assessed at baseline and 6 months. RESULTS: The WL group lost more body weight (WL: -8.6% vs. WS: -1.7%, p < 0.01), resulting in a reduction in fat mass at each region only following WL (all p < 0.05). The decline in the ratio of android/gynoid fat mass also was significant only following WL, resulting in greater declines than WS (mean [95% CI]; WL: -0.026 [-0.040 to -0.011] vs. WS: 0.003 [-0.012 to 0.019] g, p < 0.01). The change in the ratio of visceral/subcutaneous abdominal fat mass was not significant in either group and did not differ between groups (WL: 0.65 [-0.38 to 1.68] vs. WS: 0.05 [-1.00 to 1.10] g, p = 0.42). In general, the improvements in glucose and lipid profiles were associated with declines in fat mass at the gynoid and android regions (r's = 0.20-0.42, all p < 0.05), particularly the visceral depot but not the ratios. CONCLUSION: WL achieved via a hypocaloric, nutritionally complete, higher protein meal plan is effective in reducing body fat in the android, gynoid, and visceral depots, which relate to cardiometabolic improvements.

Effect of a hypocaloric, nutritionally complete, higher-protein meal plan on bone density and quality in older adults with obesity: a randomized trial.

Background: Dietary protein and micronutrients are important to the maintenance of bone health and may be an effective countermeasure to weight-loss-associated bone loss. Objectives: We aimed to determine the effect of a 6-mo hypocaloric, nutritionally complete, higher-protein meal plan on change in bone density and quality as compared with weight stability in older adults using a randomized post-test design. We hypothesized that participants randomly assigned to this meal plan would maintain similar bone density and quality to weight-stable controls, despite significant reductions in body mass. Methods: Ninety-six older adults (aged 70.3 ± 3.7 y, 74% women, 27% African American) with obesity [body mass index (kg/m2): 35.4 ± 3.3] were randomly assigned to a 6-mo hypocaloric, nutritionally complete, higher-protein meal plan targeting ≥1.0 g protein · kg body weight-1 · d-1 [weight-loss (WL) group; n = 47] or to a weight-stability (WS) group targeting 0.8 g protein · kg body weight-1 · d-1, the current Recommended Dietary Allowance (n = 49). The primary outcome was total hip bone mineral density (BMD), with femoral neck BMD, lumbar spine BMD, and lumbar spine trabecular bone score (TBS) as secondary outcomes, all assessed at baseline and 3 and 6 mo with dual-energy X-ray absorptiometry. Results: Baseline total hip, femoral neck, and lumbar spine BMDs were 1.016 ± 0.160, 0.941 ± 0.142, and 1.287 ± 0.246 g/cm2, respectively; lumbar TBS was 1.398 ± 0.109. Despite significant weight loss achieved in the WL group (6.6 ± 0.4 kg; 8.6% ± 0.4% of baseline weight), 6-mo regional BMD estimates were similar to those in the WS group (all P > 0.05). Lumbar spine TBS significantly increased at 6 mo in the WL group (mean: 1.421; 95% CI: 1.401, 1.441) compared with the WS group (1.390: 95% CI: 1.370, 1.409; P = 0.02). Conclusions: Older adults following a hypocaloric, nutritionally complete, higher-protein meal plan maintained similar bone density and quality to weight-stable controls. Our data suggest that adherence to this diet does not produce loss of hip and spine bone density in older adults and may improve bone quality. This trial was registered at clinicaltrials.gov as NCT02730988.

Effect of an Energy-Restricted, Nutritionally Complete, Higher Protein Meal Plan on Body Composition and Mobility in Older Adults With Obesity: A Randomized Controlled Trial.

BACKGROUND: Increasing protein content of the diet might be an effective strategy to preserve muscle mass in older adults undergoing caloric restriction, thereby preserving muscle function. METHODS: Ninety-six older adults (70.3 ± 3.7 years, 74% women, 27% African American) with obesity (35.4 ± 3.3 kg/m2; 47% total body fat) were randomized to a 6-month higher protein (providing 1.2-1.5 g/kg/d) weight loss (WL) program, utilizing the Medifast 4&2&1 Plan, or to weight stability (WS). Dual-energy x-ray absorptiometry-acquired total body mass and composition, and fast gait speed over 400 m was assessed at baseline, 3, and 6 months. RESULTS: At baseline, dual-energy x-ray absorptiometry-acquired total body, fat, and lean masses were 95.9 ± 14.6, 44.6 ± 7.6, and 48.7 ± 9.5 kg, respectively, and 400-m gait speed was 1.17 ± 0.20 m/s. Total body mass was significantly reduced in the WL group (-8.17 [-9.56, -6.77] kg) compared with the WS group (-1.16 [-2.59, 0.27] kg), with 87% of total mass lost as fat (WL: -7.1 [-8.1, -6.1] kg; -15.9% change from baseline). A differential treatment effect was not observed for change in lean mass (WL: -0.81 [-1.40, -0.23] kg vs WS: -0.24 [-0.85, 0.36] kg). Four-hundred-meter gait speed was also unchanged from baseline although trends suggest slightly increased gait speed in the WL group [0.01 (-0.02, 0.04) m/s] compared with the WS group [-0.02 (-0.05, 0.01) m/s]. CONCLUSION: Intentional weight loss using a high-protein diet is effective in producing significant total body mass and fat mass loss, while helping preserve lean body mass and mobility, in relatively high-functioning older adults with obesity.

Maintenance of Physical Function 1 Year After Exercise Intervention in At-Risk Older Adults: Follow-up From the LIFE Study.

Background: Structured physical activity interventions delay the onset of disability for at-risk older adults. However, it is not known if at-risk older adults continue to participate in physical activity or maintain mobility benefits after cessation of structured intervention. Methods: One thousand six hundred and thirty-five sedentary men and women aged 70-89 years with Short Physical Performance Battery (SPPB) scores of 9 or less and able to walk 400 m were randomized to a structured, moderate-intensity physical activity (PA) program consisting of center-based (twice/week) and home-based (three to four times per week) aerobic, resistance, and flexibility training or a health education (HE) program combined with upper extremity stretching. Results: Most of the participants (88% of HE and 87% of PA) returned for a follow-up visit (POST) 1 year after cessation of formal intervention. The HE group reported about 1-hour less activity per week than the PA group at end of intervention (LAST TRIAL; -68.9; 95% confidence interval [CI] = -86.5 to -51.3) but similar weekly activity at POST (-13.5; 95% CI = -29.5 to 2.47). SPPB did not differ between the two groups at LAST TRIAL (-0.06; 95% CI = -0.31 to 0.19) nor POST (-0.18; 95% CI = -0.45 to 0.088). Conclusions: Although sedentary at-risk older adults increased their physical activity during a structured physical activity intervention, they did not continue at this level following the cessation of intervention. Future exercise interventions need to include novel methods to support older adults in continued physical activity following structured interventions.

Weighted Vest Use during Dietary Weight Loss on Bone Health in Older Adults with Obesity.

BACKGROUND: To examine the effects of daily weighted vest use during a dietary weight loss intervention, on (a) hip and spine bone mineral density (aBMD), and (b) biomarkers of bone turnover, in older adults with obesity. METHODS: 37 older (70.1 ± 3.0 years) adults with obesity (BMI=35.3 ± 2.9) underwent a 22 week dietary weight loss intervention (1100-1300 kcal/day) with (Diet+Vest; n=20) or without (Diet; n=17) weighted vest use (goal: 10+ h/day; weight added incrementally based on amount of weight lost). Total body weight; DXA-acquired aBMD of the total hip, femoral neck and lumbar spine; and biomarkers of bone turnover (OC, BALP, P1NP, CTX) were measured at baseline and follow up. General linear models, adjusted for baseline values of the outcome and gender, were used to examine intervention effects. RESULTS: Average weight loss was significant in both groups (-11.2 ± 4.4 kg and -11.0 ± 6.3 kg, Diet+Vest and Diet groups, respectively), with no difference between groups (p=0.91). Average weighted vest use was 6.7 ± 2.2 h/day. No significant changes in aBMD or biomarkers were observed, although trends were noted for total hip aBMD and BALP. Loss in total hip aBMD was greater in the Diet group compared with Diet+Vest (Δ: -18.7 [29.3, -8.1] mg/cm2 versus -6.1 [-15.7, 3.5] mg/cm2; p=0.08). BALP increased in the Diet+Vest group by 3.8% (Δ: 0.59 [-0.33, 1.50] µg/L) and decreased by -4.6% in the Diet group (Δ: -0.70 [-1.70, 0.31] µg/L, p=0.07). CONCLUSION: Weighted vest use during weight loss may attenuate loss of hip aBMD and increase bone formation in older adults with obesity. Further study is warranted.

Gait speed response to aerobic versus resistance exercise training in older adults.

BACKGROUND: Little is known about the comparative effect of aerobic training (AT) versus resistance training (RT) on gait speed, a strong predictor of disability. AIMS: To compare the effect of AT versus RT on gait speed and other functional measures. METHODS: Overweight and obese [body mass index (BMI) ≥27.0 kg/m2] sedentary men and women aged 65-79 years engaged in 5 months of either 4 days/weeks moderate-intensity treadmill walking, AT, (n = 44) or 3 days/weeks moderate-intensity RT (n = 56). Usual-pace gait speed, fast-pace gait speed and short physical performance battery (SPPB) were evaluated in all participants before and after training. Peak oxygen consumption (VO2peak) was assessed in AT participants only, and knee extensor strength was assessed in RT participants. RESULTS: Both AT and RT resulted in clinically significant improvements in usual-pace gait speed (0.08 ± 0.14 and 0.08 ± 0.17 m/s, respectively, both p < 0.05) and SPPB (0.53 ± 1.40 and 0.53 ± 1.20 points, both p < 0.05) and chair rise time (-1.2 ± 3.2 and -1.7 ± 3.0 s, p < 0.05). Only AT improved fast-pace gait speed (0.11 ± 0.10 m/s, p < 0.05). In the RT participants, lower baseline knee strength was associated with less improvement in usual-pace gait speed. In AT participants, lower baseline VO2peak was associated with less improvement in chair rise time and self-reported disability. DISCUSSION: While both AT and RT improved usual-pace gait speed, only AT improved fast-pace gait speed. Lower baseline fitness was associated with less improvement with training. CONCLUSION: Research to directly compare which mode of training elicits the maximum improvement in older individuals with specific functional deficits could lead to better intervention targeting.

Effect of Statin Use on Mobility Disability and its Prevention in At-risk Older Adults: The LIFE Study.

BACKGROUND: HMG-CoA reductase inhibitors (statins) are among the most commonly prescribed classes of medications. Although their cardiovascular benefits and myalgia risks are well documented, their effects on older adults initiating an exercise training program are less understood. METHODS: 1,635 sedentary men and women aged 70-89 years with Short Physical Performance Battery (SPPB) score of 9 or below and were able to walk 400 m were randomized to a structured, moderate-intensity physical activity (PA) program consisting of both center-based (twice/wk) and home-based (3-4 times/wk) aerobic, resistance, and flexibility training or to a health education (HE) program combined with upper extremity stretching. RESULTS: Overall, the PA intervention was associated with lower risk of major mobility disability (hazard ratio [HR] = 0.82; 95% confidence interval [CI] = 0.69-0.98). The effect was similar (p value for interaction = .62) in both statin users (PA n = 415, HE n = 412; HR = 0.86, 95% CI = 0.67-1.1) and nonusers (PA n = 402, HE n = 404; HR = 0.78, 95% CI = 0.61-1.01). Attendance was similar for statin users (65%) and nonusers (63%). SPPB at 12 months was slightly greater for PA (8.35±0.10) than for HE (7.94±0.10) in statin users but not in nonusers (PA 8.25±0.10, HE 8.16±0.10), though the interaction effect was not statistically significant. Self-reported PA levels were not different between statin users and nonusers. CONCLUSIONS: Although statins have been associated with adverse effects on muscle, data from the LIFE Study show that statin users and nonusers both benefit from PA interventions. Older adults who require statin medications to manage chronic medical conditions and are sedentary will be able to benefit from interventions to increase PA.