Laura A. Talbot

Accelerated Longitudinal Decline of Aerobic Capacity in Healthy Older Adults

Background—The ability of older persons to function independently is dependent largely on the maintenance of sufficient aerobic capacity and strength to perform daily activities. Although peak aerobic capacity is widely recognized to decline with age, its rate of decline has been estimated primarily from cross-sectional studies that may provide misleading, overly optimistic estimates of aging changes. Methods and Results—To determine longitudinal rate of change in aerobic capacity and the influence of age, gender, and physical activity on these changes, we performed serial measurements of peak treadmill oxygen consumption (peak &OV0312;o2) in 375 women and 435 men ages 21 to 87 years from the Baltimore Longitudinal Study of Aging, a community-dwelling cohort free of clinical heart disease, over a median follow-up period of 7.9 years. A linear mixed-effects regression model was used to calculate the predicted longitudinal 10-year rate of change in peak &OV0312;o2, expressed in milliliters per minute, for each age decade from the 20s through the 70s after adjustment for self-reported leisure-time physical activity. A longitudinal decline in peak &OV0312;o2 was observed in each of the 6 age decades in both sexes; however, the rate of decline accelerated from 3% to 6% per 10 years in the 20s and 30s to >20% per 10 years in the 70s and beyond. The rate of decline for each decade was larger in men than in women from the 40s onward. Similar longitudinal rates of decline prevailed when peak &OV0312;o2 was indexed per kilogram of body weight or per kilogram of fat-free mass and in all quartiles of self-reported leisure-time physical activity. When the components of peak &OV0312;o2 were examined, the rate of longitudinal decline of the oxygen pulse (ie, the O2 utilization per heart beat) mirrored that of peak &OV0312;o2, whereas the longitudinal rate of heart rate decline averaged only 4% to 6% per 10 years, and accelerated only minimally with age. Conclusions—The longitudinal rate of decline in peak &OV0312;o2 in healthy adults is not constant across the age span in healthy persons, as assumed by cross-sectional studies, but accelerates markedly with each successive age decade, especially in men, regardless of physical activity habits. The accelerated rate of decline of peak aerobic capacity has substantial implications with regard to functional independence and quality of life, not only in healthy older persons, but particularly when disease-related deficits are superimposed.

Falls in young, middle-aged and older community dwelling adults: perceived cause, environmental factors and injury

BackgroundFalls in older people have been characterized extensively in the literature, however little has been reported regarding falls in middle-aged and younger adults. The objective of this paper is to describe the perceived cause, environmental influences and resultant injuries of falls in 1497 young (20–45 years), middle-aged (46–65 years) and older (> 65 years) men and women from the Baltimore Longitudinal Study on Aging.MethodsA descriptive study where participants completed a fall history questionnaire describing the circumstances surrounding falls in the previous two years.ResultsThe reporting of falls increased with age from 18% in young, to 21% in middle-aged and 35% in older adults, with higher rates in women than men. Ambulation was cited as the cause of the fall most frequently in all gender and age groups. Our population reported a higher percentage of injuries (70.5%) than previous studies. The young group reported injuries most frequently to wrist/hand, knees and ankles; the middle-aged to their knees and the older group to their head and knees. Women reported a higher percentage of injuries in all age groups.ConclusionThis is the first study to compare falls in young, middle and older aged men and women. Significant differences were found between the three age groups with respect to number of falls, activities engaged in prior to falling, perceived causes of the fall and where they fell.

Leisure-time physical activities and their relationship to cardiorespiratory fitness in healthy men and women 18-95 years old.

PURPOSE We examined leisure-time physical activities (LTPA) and their contribution to peak oxygen consumption (VO2) in healthy men (N = 619) and women (N = 497) aged 18-95 yr (mean 51 +/- 17) who were participants of the Baltimore Longitudinal study of Aging. METHODS Calculations of LTPA were based on the average self-reported time spent performing 97 activities and converted into MET-min x 24 h(-1). The activities were divided into three levels of LTPA based on absolute intensity. Peak VO2 was determined from a maximal treadmill exercise test. RESULTS Total LTPA was inversely related to age in both sexes (r = -0.26, P < 0.0001 in men and r = -0.23, P < 0.0001 in women), mediated primarily by less high-intensity activities in older subjects, with only minor differences in moderate- and low-intensity activities across age. Peak VO2 correlated positively with LTPA; the correlations were strongest for high-intensity LTPA (r = 0.33 in men and 0.27 in women, each P < 0.0001), intermediate for moderate-intensity activity (r = 0.12, P < 0.004 in men and r = 0.17, P < 0.0001 in women) and minimal for low-intensity activity (r = 0.08, P = 0.05 in men and r = 0.06, P = 0.20 in women). On univariate analysis, total LTPA accounted for 12.9% of peak VO2 variance for men and 10.6% for women. By multivariate analysis, LTPA independently accounted for 1.6% of the peak VO2 variance in men and 1.8% in women after controlling for age and body mass index. CONCLUSIONS In healthy adults across a broad age range, LTPA is a relatively minor independent contributor to aerobic capacity.

Effect of Blood Pressure and Diabetes Mellitus on Cognitive and Physical Functions in Older Adults: A Longitudinal Analysis of the Advanced Cognitive Training for Independent and Vital Elderly Cohort

Objectives: To evaluate the effect of blood pressure (BP) and diabetes mellitus (DM) on cognitive and physical performance in older, independent‐living adults.

Cognitive function in normal-weight, overweight, and obese older adults : An analysis of the advanced cognitive training for independent and vital elderly cohort

Objectives: To assess how elevated body mass index (BMI) affects cognitive function in elderly people.

Metabolic Demands of Body Armor on Physical Performance in Simulated Conditions

The purpose of this study was to examine physical work performance, energy cost, and physiological fatigue in military personnel during simulated operational conditions. Using a within-subject, repeated-measures design, 34 military personnel volunteered to undergo two experimental conditions: with body armor (BA+) and without BA (BA-). Subjects walked on a treadmill for 30 minutes and completed a physical performance battery during each of two sessions, which were separated by > or = 5 days. Subjects with BA+ as compared with BA- had significantly greater increases in: oxygen uptake (VO2) at slow (16.8 +/- 1.5 vs. 18.8 +/- 1.7 mL x kg(-1) x min(-1)) and moderate paces (34.8 +/- 3.9 vs. 40.8 +/- 5.0 mL x kg(-1) x min(-1)); blood lactate at a moderate pace (4.0 +/- 2.4 vs. 6.7 +/- 2.6 mmol/L); heart rate at slow (107 +/- 14 vs. 118 +/- 16 beats per minute) and moderate paces (164 +/- 16 vs. 180 +/- 13 beats per minute); and ratings of perceived physical exertion at slow (8.4 +/- 1.5 vs. 10.4 +/- 1.8) and moderate paces (14.3 +/- 2.3 vs. 16.7 +/- 2.1). Physical tasks were significantly affected by BA: under BA+, men performed 61% fewer pull-ups and womens hang time was reduced by 63%; stair stepping was reduced by 16% for both men and women. BA significantly impacted the physical work capacity of militarily relevant tasks. Specifically, wearing BA significantly increased VO2 when walking at both slow and moderate paces. The potential for physical exhaustion is high and performance of physical tasks is markedly impaired when wearing BA.

Effects of Gender and Body Adiposity on Physiological Responses to Physical Work While Wearing Body Armor

The purpose of this study was to identify the effects of gender and body adiposity on physiological responses to the stress of wearing body armor. Using a within-subject, repeated-measures design, 37 military personnel volunteered to undergo two experimental conditions, with body armor and without body armor. Female and male subjects with body armor, compared to those without body armor, had no significant differences in percentage increases in aerobic capacity, heart rate, or respiratory rate while walking at slow or moderate pace. However, women, as compared to men, had a significantly increased difference in the rating of perceived physical exertion between wearing and not wearing body armor at a slow pace. Fourteen subjects were not able to complete treadmill testing while wearing body armor because of volitional fatigue and/or limiting dyspnea. Body fat was the best single predictor of treadmill test completion.

Use of bioelectrical impedance analysis in the evaluation, treatment, and prevention of overweight and obesity

Purpose: To present an overview of bioelectrical impedance analysis (BIA) and to familiarize nurse practitioners (NPs) with the potential benefits of using BIA in prevention, monitoring, and long‐term follow‐up of healthy individuals and those with chronic conditions (e.g., obesity). Data sources: Original research articles and comprehensive review articles identified through Medline, CINAHL, OVID, and electrical engineering databases. Conclusions: Obtaining serial measurements of percent body fat using BIA can identify patients at greatest health risk and gives NPs an additional tool to assess treatment response in patients seeking to lose or maintain body weight and/or increase muscle mass. Implications for practice: Traditionally, height/weight tables and body mass index have been used to assess body composition and diagnose overweight and obesity. More recently, BIA has emerged as a portable and simple‐to‐operate instrument to evaluate body composition in the clinical setting.

Army Physical Fitness Test Scores Predict Coronary Heart Disease Risk in Army National Guard Soldiers

An increased rate of cardiac symptoms at combat theater hospitals brings concerns about the predeployment health of Army National Guard (ARNG) soldiers on the basis of older age, lower fitness level, and sedentary lifestyle than active duty troops. The purpose of this study was to examine the association of physical fitness, reported physical activity (PA), and coronary risk factors to calculated 10-year hard coronary heart disease (CHD) risk in 136 ARNG soldiers, aged 18-53 years, who failed the 2-mile run of the Army Physical Fitness Test (APFT). The APFT score, derived from a composite of 2-mile run time, sit-ups, and push-ups, related inversely to 10-year CHD risk (r = -0.23, p < 0.01) but no relationship with CHD risk was observed for PA. APFT scores were positively associated with high-density lipoprotein (HDL) cholesterol and inversely with triglycerides, total cholesterol:HDL ratio, diastolic blood pressure, and body mass index (BMI). No relationship existed between PA and any of the CHD risk factors. We conclude that a higher APFT score is associated with a healthier CHD risk factor profile and is a predictor of better predeployment cardiovascular health.

A pedometer-based intervention to improve physical activity, fitness, and coronary heart disease risk in national guard personnel

To compare the effects of a pedometer-based behavioral intervention (Fitness for Life [FFL] program) and a traditional high-intensity fitness (TRAD) program on physical activity (PA), Army Physical Fitness Test (APFT), and coronary heart disease risk factors in Army National Guard members who failed the APFT 2-mile run. From a pool of 261 Army National Guard, a total of 156 were randomized to TRAD or FFL for 24 weeks consisting of a 12-week progressive conditioning program followed by 12 weeks of maintenance. For both groups, the total APFT score and 2-mile run time/score improved from baseline to 12 weeks (FFL: down 7.4%, p = 0.03; TRAD: down 5%, p = 0.08) but at 24 weeks they had regressed toward baseline. PA improved modestly and coronary risk profile changed minimally in both groups. A pedometer-based exercise intervention had results similar to a high-intensity program for improving PA, APFT, and 2-mile run times/score. Neither group sustained the improved run times over the 12 weeks of maintenance.