Sedentary Middle-aged Adults Research Articles

The aging cardiovascular system: changes in autonomic function at rest and in response to exercise.

Tonic vagal modulation of cardiac period (R-R interval) decreases with advancing age, but is greater in middle-aged and older adults who habitually perform aerobic exercise compared with their sedentary peers. Cardiovagal baroreflex sensitivity also declines markedly with age in sedentary adults but only 50% as much in regularly exercising adults. In previously sedentary middle-aged and older adults, a 3-month program of moderate aerobic exercise increases cardiovagal baroreflex sensitivity by 25%. Tonic (basal) sympathetic nervous system (SNS) activity increases with advancing age in both sedentary and habitually exercising adults. Despite this, SNS beta-adrenergic support of energy metabolism (resting metabolic rate--RMR) declines with age in sedentary individuals. However, SNS beta-adrenergic support of RMR is maintained with age in endurance exercise-trained adults and therefore is much greater in middle-aged and older individuals who exercise regularly compared with their sedentary peers. Thus, regular aerobic (endurance) exercise modulates selective age-associated impairments in autonomic nervous system-physiological function.

Reasons for not exercising and exercise intentions: A study of middle-aged sedentary adults

The aims of this study were to assess why people do not participate in exercise and physical activity, and what might lead them to become active. More specifically, we focused on the hindrances to entering the phase of transition from a sedentary to a more active lifestyle by analysing the reasons 265 middle-aged Belgian adults gave for their inactivity. Their justifications were examined in relation to the conditions which they say would be needed for them to become more involved in regular physical activity. Factor analysis revealed that the reasons for inactivity referred to the adults' self-concept, to cognitive cost- benefit based processes and to negative emotions associated with exercise. The conditions reported to be necessary to begin exercising referred to a perceived decrease in health and to the appropriateness of the exercise offered. Discriminant analysis showed that ‘never-exercisers’ differed from ‘ex-exercisers’, and that within the subgroup of ‘ex-exercisers’ the long-term drop-outs differed from the recent drop-outs. Cluster analysis revealed three types of sedentary adults: the unconcerned, the opposed and the approachable.

Self-Efficacy and Intrinsic Motivation in Exercising Middle-Aged Adults

The present study examined the relationships between perceptions of personal capabilities and intrinsic interest for exercise participation. In the context of formerly sedentary middle-aged adults enrolled in a program of aerobic exercise, the role played by multidimensional intrinsic interest for exercise in the generation of self-efficacy when statistically controlling for initial efficacy, physiological status, and previous exercise behavior was determined. Hierarchical multiple regression analyses revealed that the dimensions of perceived competence and effort contributed significant unique variance to subsequent self-efficacy. The results are discussed in terms of how sources of efficacy enhancing information might be manipulated in the exercise environment to best facilitate perceptions of personal capabilities for exercise in older males and females.

Self-efficacy and the maintenance of exercise participation in older adults.

The role played by exercise self-efficacy in the maintenance of exercise participation of previously sedentary middle-aged adults 4 months after the termination of a formal exercise program is reported. Correlational and multiple regression analyses examined the influence of self-efficacy, physiological (aerobic capacity, sex, body composition), and behavioral (past exercise frequency and intensity) parameters in the maintenance of exercise participation. Self-efficacy significantly predicted exercise behavior at follow-up when controlling for biological and behavioral influences. Aerobic capacity, exercise efficacy, and exercise behavior in combination were significantly related to current energy expenditure in aerobic physical activity. The discussion focuses on the need to examine the impact of different correlates of exercise behavior at different stages of the exercise process.

Differences in developmental movement patterns used by active versus sedentary middle-aged adults coming from a supine position to erect stance.

The purpose of this study was twofold: (1) to further validate categories for the movement pattern of supine to standing in adults and (2) to evaluate the influence physical activity might have on the movement patterns used for rising. Seventy-two adults, between 30 and 39 years of age (mean = 34.1, SD = 2.8), performed the rising task while being videotaped. Subjects were divided into three groups by self-reports of level of physical activity (daily to rarely). Individual videotaped trials were classified using the previously described categories. Comparisons among the activity-level groups revealed that more active subjects demonstrated more developmentally advanced movement patterns in the righting task, consistent with earlier research on older adults. Results suggest that lifestyle patterns of regular, moderate physical activity may influence how a person performs the basic righting task of coming from a supine to a standing position. This investigation also provided additional support for the use of developmental sequences for the movement pattern of supine to standing.

The role of efficacy cognitions in the prediction of exercise behavior in middle-aged adults.

The present study adopted a social cognitive framework to examine the role played by perceptions of personal efficacy in adherence to exercise behavior in sedentary middle-aged adults. Subjects were followed for 5 months in order to study the process of exercise as it moved through the adoption to maintenance stage of the behavior. Participation rates paralleled those reported elsewhere in the literature. Path analytic techniques examined the role over time of efficacy, perceptual, and behavioral indicators of frequency and intensity of exercise. Self-efficacy cognitions were shown to predict adoption of exercise behavior but previous behavior proved to be the strongest predictor of subsequent exercise participation. Results are discussed in terms of examining process versus static design models in exercise and physical activity research. Implications for future research and health promotion are suggested.

Endurance training and body composition of the elderly

Body composition was studied in subjects from the seventh decade of life (13 M, 25F), observations being made on recruitment and at selected points over a 1-year program of endurance training. As at younger ages, the women initially had more subcultaneous fat than the men, particularly over the limbs. In both sexes, excess weights (9.3 kg. M; 8.1 kg, F) and average skinfold radings (16.2 mm, M; 21.1mm, F) were greater than in younger adults. Edurance training (1 hr of supervised exercise, 150-200 kcal persession, nominal four sessions per week) progressively reduced skinfold readings, by an average of 1.6 mm at 7 weeks, by 2.4 dependent upon the intensity and the frequency of exercise undertaken by the individual. Total body potassium (40K determinations) agreed well with previous studies of older subjects. Body fat estimated form 40K showed a fair correlation with skinfold estimates of body fat (r=0.69, M; 0.93, F), but absolute precentages were higher by 40K(36.6%, M; 48.7%, F) than by subcutaneous fat measurements (20%, M;32% F). Body potassium increased by 4% over the year of training, 70% of this change, occurring between the 14th and the 52nd week of conditioning. Small gains were also recorded in arm circumference, grip strenght (R but not L) and knee extension force. Neutron activation data showed that both sexes had lower initial bone calcium counts than sedentary middle-aged adults. The sample as a whole showed no calcium loss over the year of training, but the group taking the least exercise did show a significant loss (P less than 0.05). Modest endurance training of an elderly population seems not only to correct loss of cardiorespiratory condition, but also to induce favorable changes in body fat and lean mass.