Lewis A. Lipsitz

Exercise Training and Nutritional Supplementation for Physical Frailty in Very Elderly People

BACKGROUND Although disuse of skeletal muscle and undernutrition are often cited as potentially reversible causes of frailty in elderly people, the efficacy of interventions targeted specifically at these deficits has not been carefully studied. METHODS We conducted a randomized, placebo-controlled trial comparing progressive resistance exercise training, multinutrient supplementation, both interventions, and neither in 100 frail nursing home residents over a 10-week period. RESULTS The mean (+/- SE) age of the 63 women and 37 men enrolled in the study was 87.1 +/- 0.6 years (range, 72 to 98); 94 percent of the subjects completed the study. Muscle strength increased by 113 +/- 8 percent in the subjects who underwent exercise training, as compared with 3 +/- 9 percent in the nonexercising subjects (P < 0.001). Gait velocity increased by 11.8 +/- 3.8 percent in the exercisers but declined by 1.0 +/- 3.8 percent in the nonexercisers (P = 0.02). Stair-climbing power also improved in the exercisers as compared with the nonexercisers (by 28.4 +/- 6.6 percent vs. 3.6 +/- 6.7 percent, P = 0.01), as did the level of spontaneous physical activity. Cross-sectional thigh-muscle area increased by 2.7 +/- 1.8 percent in the exercisers but declined by 1.8 +/- 2.0 percent in the nonexercisers (P = 0.11). The nutritional supplement had no effect on any primary outcome measure. Total energy intake was significantly increased only in the exercising subjects who also received nutritional supplementation. CONCLUSIONS High-intensity resistance exercise training is a feasible and effective means of counteracting muscle weakness and physical frailty in very elderly people. In contrast, multi-nutrient supplementation without concomitant exercise does not reduce muscle weakness or physical frailty.

Consensus statement on the definition of orthostatic hypotension, neurally mediated syncope and the postural tachycardia syndrome

Roy Freeman • Wouter Wieling • Felicia B. Axelrod • David G. Benditt • Eduardo Benarroch • Italo Biaggioni • William P. Cheshire • Thomas Chelimsky • Pietro Cortelli • Christopher H. Gibbons • David S. Goldstein • Roger Hainsworth • Max J. Hilz • Giris Jacob • Horacio Kaufmann • Jens Jordan • Lewis A. Lipsitz • Benjamin D. Levine • Phillip A. Low • Christopher Mathias • Satish R. Raj • David Robertson • Paola Sandroni • Irwin Schatz • Ron Schondorff • Julian M. Stewart • J. Gert van Dijk

The effects of exercise on falls in elderly patients. A preplanned meta-analysis of the FICSIT Trials. Frailty and Injuries: Cooperative Studies of Intervention Techniques

OBJECTIVE To determine if short-term exercise reduces falls and fall-related injuries in the elderly. DESIGN A preplanned meta-analysis of the seven Frailty and Injuries: Cooperative Studies of Intervention Techniques (FICSIT)--independent, randomized, controlled clinical trials that assessed intervention efficacy in reducing falls and frailty in elderly patients. All included an exercise component for 10 to 36 weeks. Fall and injury follow-up was obtained for up to 2 to 4 years. SETTING Two nursing home and five community-dwelling (three health maintenance organizations) sites. Six were group and center based; one was conducted at home. PARTICIPANTS Numbers of participants ranged from 100 to 1323 per study. Subjects were mostly ambulatory and cognitively intact, with minimum ages of 60 to 75 years, although some studies required additional deficits, such as functionally dependent in two or more activities of daily living, balance deficits or lower extremity weakness, or high risk of falling. INTERVENTIONS Exercise components varied across studies in character, duration, frequency, and intensity. Training was performed in one area or more of endurance, flexibility, balance platform, Tai Chi (dynamic balance), and resistance. Several treatment arms included additional nonexercise components, such as behavioral components, medication changes, education, functional activity, or nutritional supplements. MAIN OUTCOME MEASURES Time to each fall (fall-related injury) by self-report and/or medical records. RESULTS Using the Andersen-Gill extension of the Cox model that allows multiple fall outcomes per patient, the adjusted fall incidence ratio for treatment arms including general exercise was 0.90 (95% confidence limits [CL], 0.81, 0.99) and for those including balance was 0.83 (95% CL, 0.70, 0.98). No exercise component was significant for injurious falls, but power was low to detect this outcome. CONCLUSIONS Treatments including exercise for elderly adults reduce the risk of falls.

What is physiologic complexity and how does it change with aging and disease

1. IntroductionA defining but elusive feature of physiologic systems istheir daunting complexity. This complexity arises from theinteraction of a myriad of structural units and regulatoryfeedback loops that operate over a wide range of temporaland spatial scales, enabling the organism to adapt to thestresses of everyday life. Quantifying and modeling theremarkable and often bewildering repertoire of behaviorsexhibited by living organisms is one of the major challengesof contemporary science [4,7]. The combination of nonlin-earity and nonstationarity, more the rule than the exceptionin the output of physiologic systems, poses a major chal-lenge to conventional biostatistical assessments and stan-dard reductionist modeling stratagems. To describe andquantify the mechanisms of these “nonhomeostatic” behav-iors, investigators have employed new techniques derivedfrom complexity theory, including fractal analysis and non-linear dynamics. The appropriate application and interpre-tation of such metrics, however, remains incompletely ex-plored. What is clear is that reliance on any single test maygive a misleading representation of physiological complexity.In this issue, Vaillancourt and Newell critique and sug-gest modifications to a general dynamical model of patho-physiology that we and others have elaborated over the pasttwo decades [5,6,8,10,13,14,16,20,21,27]. The theory ofcomplexity loss in aging and disease, as currently formu-lated, has two central postulates:1. The output of healthy systems, under certain param-eter conditions, reveals a type of complex variabilityassociated with long-range (fractal) correlations,along with distinct classes of nonlinear interactions;2. This type of multi-scale, nonlinear complexity breaksdown with aging and disease, reducing the adaptivecapabilities of the individual.The term nonlinear applies to systems whose compo-nents interact in a non-additive way. Nonlinear couplingmay lead to an extraordinary range of dynamics, includingdifferent classes of abrupt changes, (such as bifurcations),deterministic chaos, nonlinear phase transitions, pacemakerentrainment and resetting, stochastic resonance, wave phe-nomena (including spiral waves, solitons, and scroll waves),emergent phenomena, and certain types of fractal scaling.Understanding the specific classes of nonlinear interactionsseen in healthy physiology and characterizing their pertur-bations with aging and disease is just beginning [4,16,27].The term fractal applies to complex-like objects, whichmay be generated by stochastic or nonlinear deterministicmechanisms. Fractal objects show self-similarity (scale-in-variance), such that the smaller-scale structure resemblesthe larger-scale form [10]. Examples in anatomy include theHis-Purkinje network and the tracheobronchial tree. Thefractal concept also extends to complex processes that lacka characteristic, or a single, time scale. Fractal processesgenerate fluctuations over multiple time scales, and theirfrequency spectra typically show an inverse power-law (1/f-like) scaling pattern. Of particular interest is a class offractal processes that demonstrates long-range correlations.This type of “memory” effect has been identified in thefluctuations of the healthy heartbeat, as well as in the inter-stride interval fluctuations in the walking patterns of healthyadults [14,15,21,22].A central caveat when applying concepts and techniquesfrom complexity theory to biomedicine is the recognition

Spectral characteristics of heart rate variability before and during postural tilt. Relations to aging and risk of syncope.

Fourier analysis of heart rate (HR) may be used to characterize overall HR variability as well as low- and high-frequency components attributable to sympathetic and vagal influences, respectively. We analyzed HR spectral characteristics of 12 healthy young (18-35 years) and 10 healthy old (71-94 years) subjects before and during 60 degrees head-up tilt. Total spectral power in the 0.01-0.40-Hz frequency range and low-frequency (0.06-0.10 Hz) and high-frequency (0.15-0.40 Hz) components of the HR power spectrum were significantly lower in old than in young subjects in supine and upright positions. To characterize and compare overall HR variability in young and old subjects, we computed the regression lines relating the log amplitude to the log frequency of the supine HR spectra (l/fx plots). The regression lines for old subjects were lower and steeper (mean slope, -0.78 [5%, 95% confidence limits (CL), -0.73, -0.83]) than in young (mean slope, -0.67 [CL, -0.62, -0.72]), indicating not only reduced overall spectral amplitude but also relatively greater attenuation of high-frequency HR components in the old subjects. This finding illustrates a novel way to quantify the loss of autonomic influences on HR regulation as a function of age. During postural tilt, HR variability was unchanged in the old subjects. For the entire group of young subjects, total HR variability increased during tilt. Six young subjects developed vasovagal syncope during tilt, enabling us to examine differences in the HR spectra of these subjects while they were asymptomatic before syncope.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Gait Alterations Independent of Speed in the Healthy Elderly: Evidence for Specific Limiting Impairments

OBJECTIVES It is not known whether changes in the biomechanics of elderly gait are related to aging per se, or to reduced walking speed in this population. The goals of the present study were to identify specific biomechanical changes, independent of speed, that might impair gait performance in healthy older people by identifying age-associated changes in the biomechanics of gait, and to determine which of these changes persist at increased walking speed. DESIGN Stereophotogrammetric and force platform data were collected. Differences in peak joint motion (kinematic) and joint moment and power (kinetic) values between healthy young and elderly subjects at comfortable and increased walking speed were measured. SETTING A gait laboratory. SUBJECTS Thirty-one healthy elderly (age 65 to 84 years) and 31 healthy young adult subjects (age 18 to 36 years), all without known neurologic, musculoskeletal, cardiac, or pulmonary problems. MAIN OUTCOME MEASURES All major peak kinematic and kinetic variables during the gait cycle. RESULTS Several kinematic and kinetic differences between young and elderly adults were found that did not persist when walking speed was increased. Differences that persisted at both comfortable and fast walking speeds were reduced peak hip extension, increased anterior pelvic tilt, and reduced ankle plantarflexion and ankle power generation. CONCLUSION Gait performance in the elderly may be limited by both subtle hip flexion contracture and ankle plantarflexor concentric weakness. Results of the current study should motivate future experimental trials of specific hip flexor stretching and ankle plantarflexor concentric strengthening exercises to preserve and potentially improve walking performance in the elderly.

Aging, muscle activity, and balance control : physiologic changes associated with balance impairment.

Older adults demonstrate increased amounts of postural sway, which may ultimately lead to falls. The mechanisms contributing to age-related increases in postural sway and falls in the elderly remain unclear. In an effort to understand age-related changes in posture control, we assessed foot center-of-pressure (COP) displacements and electromyographic data from the tibialis anterior, soleus, vastus lateralis, and biceps femoris collected simultaneously during quiet-standing trials from elderly fallers, elderly non-fallers, and healthy young subjects. Both traditional measures of COP displacements and stabilogram-diffusion analysis were used to characterize the postural sway of each group. Regression analyses were used to assess the relationship between the COP measures and muscle activity. Elderly fallers demonstrated significantly greater amounts of sway in the anteroposterior (AP) direction and greater muscle activity during quiet standing compared with the young subjects, while elderly non-fallers demonstrated significantly greater muscle activation and co-activation compared with the young subjects. No significant differences were found between elderly fallers and elderly non-fallers in measures of postural sway or muscle activity. However, greater postural sway in both the AP and mediolateral (ML) directions and trends of greater muscle activity were found in those older adults who demonstrated lower scores on clinical measures of balance. In addition, short-term postural sway was found to be significantly correlated with muscle activity in each of these groups. This work suggests that high levels of muscle activity are a characteristic of age-related declines in postural stability and that such activity is correlated with short-term postural sway. It is unclear whether increases in muscle activity preclude greater postural instability or if increased muscle activity is a compensatory response to increases in postural sway.

Aging and the complexity of cardiovascular dynamics.

Biomedical signals often vary in a complex and irregular manner. Analysis of variability in such signals generally does not address directly their complexity, and so may miss potentially useful information. We analyze the complexity of heart rate and beat-to-beat blood pressure using two methods motivated by nonlinear dynamics (chaos theory). A comparison of a group of healthy elderly subjects with healthy young adults indicates that the complexity of cardiovascular dynamics is reduced with aging. This suggests that complexity of variability may be a useful physiological marker.

Vibrating insoles and balance control in elderly people

Somatosensory function declines with age, and such changes have been associated with diminished motor performance. Input noise can enhance sensory and motor function. We asked young and elderly participants to stand quietly on vibrating gel-based insoles, and calculated sway parameters and random-walk variables. In our 27 participants, application of noise resulted in a reduction in seven of eight sway parameters in young participants and all of the sway variables in elderly participants. Elderly participants showed greater improvement than young people in two variables, mediolateral range (p=0.008), and critical mean square displacement (p=0.012). Noise-based devices, such as randomly vibrating insoles, could ameliorate age-related impairments in balance control.

Impact near the hip dominates fracture risk in elderly nursing home residents who fall

SummaryHip fractures among the elderly are a significant and rapidly growing public health problem. The prevailing view is that most hip fractures are the consequence of age-related bone loss or osteoporosis. However, because over 90% of hip fractures are the result of falls, we have undertaken a falls surveillance study to determine if factors related to the mechanics of falling are associated with increased risk of hip fracture. Case subjects with hip fracture and control subjects without hip fracture were sampled from falls recorded at the Hebrew Rehabilitation Center for Aged, a chronic care facility. Fall information was obtained by interview of the subject and witnesses if the fall was witnessed. Data were analyzed by multiple logistic regression. Increased risk of hip fracture from a fall was associated with impacting on the hip or side of the leg and potential energy associated with the fall. Quetelet, or body mass index, was inversely related to fracture risk. The adjusted odds ratio of hip fracture for a fall involving impact on the hip region was 21.7 (95% confidence interval, 8.2–58). The potential energy associated with these falls was an order of magnitude greater than the average energy required to fracture elderly, cadaveric, proximal femurs in earlier in vitro experiments. We conclude, therefore, that a fall from standing height should no longer be considered minimal trauma but rather trauma of sufficient magnitude to pose a high risk of hip fracture if impact occurs on the hip and if energy-absorbing processes are inadequate. These new findings suggest that fall mechanics play an important role in the etiology of hip fracture among the elderly.