Physical Activity Levels and Well-Being in Older Adults

The objective of this study was to identify the interconnectedness of different intensity levels of physical activity and psychological (life satisfaction and positive affect) and physical (physical health) well-being. Participants were from the National Study of Midlife in the United States with assessments in 2004 and aged 25 to 74 living in the United States were included in the analyses. We conducted bivariate correlations to examine significant relationships among the study variables. In addition, after multicollinearity among the independent variable was checked, a series of hierarchical regression analyses with physical health, positive affect, and life satisfaction as criterion variables were conducted. The results showed that light physical activities were positively associated with physical health and life satisfaction in summer, whereas light physical activities and all dependent variables were positively correlated in winter. Furthermore, engaging in moderate physical activities was positively related only with physical health. Meanwhile, vigorous physical activities were not associated with life satisfaction, physical health, and positive affect in summer and winter.

Geometry of a weight-bearing and non-weight-bearing bone in the legs of young, old, and very old men

Bone geometry is an important determinant of bone strength and is influenced by muscle pull and weight-bearing. Muscle mass and exposure to weight-bearing decrease with age and thus the purpose of the study was to compare bone geometry of the weight-bearing (tibia) and non-weight-bearing (fibula) bones of the leg in different age groups. Magnetic resonance images of the right leg were acquired in 13 young (26 yr), 13 old (66 yr), and 13 very old men (83 yr). Cortical, medullary and total cross-sectional areas (CSA) of the bones were measured at approximately one-third and two-thirds the length of the leg. Muscle CSA of the anterior, lateral and posterior compartments was measured at the proximal site. Cortical CSA was approximately 14 to 22% smaller in the elderly in the tibia but similar across age in the fibula. Medullary CSA was larger with age (approximately 5 to 65%) in both bones but approximately 15 to 440% greater in the tibia than fibula. Total CSA was similar across age in both bones. Muscle mass was similar between young and old but approximately 25% less in the very old and as a consequence, the magnitude of differences in bone geometry at proximal and distal sites varied in the two elderly groups. These findings indicate that there is a complex age-dependent interaction between muscle pull and weight-bearing. The greater age-related differences in bone geometry in the tibia suggest the weight-bearing role of the tibia makes it more susceptible than the fibula to the reduced activity typically associated with aging.

Evaluation of Differences in Bone-Mineral Density in 51 Men Age 65–93 Years: A Cross-Sectional Study

This study assessed differences in bone-mineral density (BMD) and lean and fat tissues between 5 age groups of White men age 65–93 years. Lean and fat tissues were measured with absorptiometry and anthropometry, and BMD, with dual-energy X-ray absorptiometry. Forearm, spinal, and femoral T scores were used to classify BMD as normal, osteopenic, or osteoporotic. A questionnaire evaluated previous physical activity, calcium intake, and bone fractures. Significantly lower values in body weight, lean tissue, and forearm BMD occurred in the older age groups. Significant, positive relationships were found between total lean tissue and radial, spinal, and hip BMDs. For the total group, osteopenic and osteoporotic T scores, respectively, were femoral neck 70.6% and 9.8%, radius 27.5% and 25.5%, and spine 25.5% and 7.8%. Differences in BMD values were found between levels of lifestyle factors (dietary calcium and history of previous fractures). In conclusion, elderly men should be encouraged to maintain adequate total lean tissue because of its association with BMD.

The underuse of therapy in the secondary prevention of hip fractures

There is strong evidence to indicate that individuals who sustain a hip fracture are at a greater risk of developing another. The management of such patients should include efforts to prevent future fractures, including prescribing medications that have been shown to lower hip fracture risk. Such therapies that are currently available include calcium and vitamin D supplementation, alendronic acid and risedronic acid. In addition, there is epidemiological evidence to indicate that estrogen may also decrease the risk of hip fracture. Parathyroid hormone is another agent that has shown promise in this regard and is likely to be available for clinical use in the near future. However, the rates of utilisation of these therapies among patients with hip fractures are low. It is important to emphasise that secondary prevention of hip fractures should be an integral part of the management of individuals who sustain hip fractures.

Resistance exercise and bone turnover in elderly men and women

PURPOSE

This investigation examined the effect of 6 months of high- or low-intensity resistance exercise (REX) on bone mineral density (BMD) and biochemical markers of bone turnover in adults aged 60-83 yr.

METHODS

Sixty-two men and women (68.4 +/- 6 yr) were stratified for strength and randomly assigned to a control (CON, N = 16), low-intensity (LEX, N = 24), or high-intensity (HEX, N = 22) group. Subjects participated in 6 months of progressive REX training. Subjects trained at either 50% of their one repetition maximum (1-RM) for 13 repetitions (LEX) or 80% of 1-RM for 8 repetitions (HEX) 3 times x wk(-1) for 24 wk. One set each of 12 exercises was performed. 1-RM was measured for eight exercises. BMD was measured for total body, femoral neck, and lumbar spine by dual energy x-ray absorptiometry (DXA). Serum levels of bone-specific alkaline phosphatase (BAP), osteocalcin (OC), and pyridinoline cross-links (PYD) were measured.

RESULTS

1-RM significantly increased for all exercises tested for both the HEX and LEX groups (P < and = 0.050). The percent increases in total strength (sum of all eight 1-RMs) were 17.2% and 17.8% for the LEX and HEX groups, respectively. Bone mineral density (BMD) of the femoral neck significantly (P < 0.05) increased by 1.96% for the HEX group. No other significant changes for BMD were found. OC increased by 25.1% and 39.0% for the LEX and HEX groups, respectively (P < 0.05). BAP significantly (P < 0.05) increased 7.1% for the HEX group.

CONCLUSION

These data indicate high-intensity REX training was successful for improving BMD of the femoral neck in healthy elderly subjects. Also, these data suggest REX increased bone turnover, which over time may lead to further changes in BMD.

Determinants of bone mineral density in older men and women: body composition as mediator

This study aimed to assess the relative importance of several determinants of bone mineral density (BMD) and to examine to what extent these potential determinants influence total hip BMD through body composition. The study population consisted of 522 participants (264 women and 258 men) of the Longitudinal Aging Study Amsterdam (LASA), aged 65 years and over, and living in Amsterdam and its vicinity. BMD of the total hip was measured using dual-energy X-ray absorptiometry (DXA). Potential determinants of BMD were age, weight change since age 25 years, lifestyle factors, chronic diseases, medication use, and hormonal factors. Potential mediators between the possible determinants and BMD were two measures of body composition: fat mass (FM) and appendicular muscle mass (AMM). Multiple regression analyses including all potential determinants in one model without body composition identified age, weight change, walking activity, and sex hormone-binding globulin (SHBG) as independent determinants for total hip BMD in women. In men, current smoking, participation in sports, and parathyroid hormone (PTH) concentration were independently associated with total hip BMD. When total hip BMD was regressed on the potential determinants and each measure of body composition, it appeared that FM, and to a lesser extent, muscle mass (MM), were independently related to BMD. In women, adjustment for FM reduced the strength of the associations of weight change, walking activity, and SHBG with total hip BMD. Adjustments for MM did not influence the associations between the determinants and BMD. In men, neither FM nor MM appeared to play a mediating role between the determinants and BMD. It can be concluded that (1) FM and MM are strong independent determinants of total hip BMD and that (2) FM possibly plays a mediating role in the association of weight change, walking activity, and SHBG with total hip BMD in women.

Lateral stability, sensorimotor function and falls in older people

AIMS

To design simple tests of lateral stability for assessing balance in older people and to determine whether poor performances in these tests are associated with impaired vision, lower limb sensation, quadriceps strength, simple reaction time, and falling in this group.

DESIGN

A cross-sectional and retrospective study.

SETTING

Falls and Balance Laboratory, Prince of Wales Medical Research Institute.

PARTICIPANTS

One hundred fifty-six community-dwelling men and women aged 63-90 years (mean age 76.5, SD = 5.1).

OUTCOME MEASURES

The maximal lateral sway in a near-tandem stability test with eyes open and closed and the necessity of taking a protective step in the near-tandem stability test with eyes closed.

RESULTS

All 156 subjects could complete the near-tandem stability test with eyes open, but only 99 subjects (63.5%) could undertake the test with eyes closed without taking a protective step. Subjects with a history of falls had increased lateral sway both with eyes open and eyes closed as well as poorer visual acuity, proprioception, and quadriceps strength. Fallers were also significantly more likely to take a protective step when undertaking the near-tandem stability test with eyes closed. Multiple regression analysis revealed that impaired lower limb proprioception, quadriceps strength, and reaction time were the best predictors of increased maximal sway in the near-tandem stability test with eyes open. Reduced proprioception and quadriceps strength, in addition to age, were also found to be the best determinants of the necessity of taking a protective step in the near-tandem stability test with eyes closed.

CONCLUSIONS

The study findings identify simple new tests that are associated with falling in older people and elucidate the relative importance of specific physiological systems in the maintenance of lateral stability.

A weight-bearing, water-based exercise program for osteopenic women: its impact on bone, functional fitness, and well-being

OBJECTIVE

To evaluate the effects of a weight-bearing, water-based, exercise program designed for women with low bone mass.

DESIGN

A test-retest cross-sectional, prospective study.

SETTING

Community-dwelling women from a Canadian city.

PARTICIPANTS

Seventy-seven postmenopausal women, 50 to 70 years of age, with spinal or femoral bone density below the fracture threshold.

INTERVENTION

Subjects exercised in a pool with waist-high water for 60 minutes, 3 days a week, over a 12-month period. Forty minutes of each session were devoted to successive jumps and muscular exercises designed to promote bone accretion, strength, and endurance.

MAIN OUTCOME MEASURES

Spinal and femoral bone mineral density (BMD) measured by dual-energy X-ray absorptiometry, functional fitness (flexibility, coordination, agility, strength/endurance, and cardiorespiratory endurance) assessed with the American Alliance for Health, Physical Education, Recreation and Dance battery, and psychological states evaluated with Dupuy's General Well-Being Schedule.

RESULTS

Spinal BMD decreased significantly (p < .001), whereas there was no change in femoral neck BMD (p = .90). Four of the parameters chosen to assess functional fitness, namely, flexibility, agility, strength/endurance, and cardiorespiratory endurance, were affected positively by the exercise program (all p values < .001). Psychological well-being also improved significantly after participation in the exercise program (p < .001).

CONCLUSION

The intervention was successful in improving the functional fitness and psychological well-being of the participants, despite a lack of effect on the skeletal system. Future studies are needed to identify water exercises that are safe yet exert enough stress on the bones to initiate a bone response.

Impact of a 12-month exercise program on the physical and psychological health of osteopenic women

OBJECTIVE

To describe the effect of a supervised physical activity program on the physical and psychological health of osteopenic women.

DESIGN

A randomized controlled trial.

SETTING

Sherbrooke, Quebec, Canada.

PARTICIPANTS

A total of 124 community-living postmenopausal women, between 50 and 70 years of age, with low bone mass took part in the study.

INTERVENTION

Subjects allocated to the experimental group performed weight-bearing exercises (walking, stepping up and down from benches), aerobic dancing, and flexibility exercises for 60 minutes, three times a week, over a period of 12 months. All subjects were invited to attend bi-monthly educational seminars covering topics related to osteoporosis.

OUTCOME MEASURES

Spinal and femoral bone mineral density (BMD), functional fitness (flexibility, coordination, agility, strength/endurance, cardiorespiratory endurance), psychological well-being, back pain intensity, and self-perceived health.

RESULTS

Spinal BMD stabilized in the exercisers while decreasing significantly in the controls (P = .031). No change in femoral BMD was observed in either group (P = .597). Four of the five parameters chosen to evaluate functional fitness, namely flexibility, agility, strength, and endurance, were affected positively by the exercise program (all P < .01). Adjusting for prescores by means of an analysis of covariance revealed a significant difference between the groups in psychological well-being, which favored the exercisers (P = .012). After 12 months, back pain reported by exercisers was lower than that reported by controls (P = .008). Finally, self-perceived health increased in the exercise group, whereas no difference was observed in the control group (P = .790).

CONCLUSION

These results suggest that after 12 months, exercising can produce a significant increase above initial levels in the functional fitness, well-being, and self-perceived health of osteopenic women. Intensity of back pain can also be lowered by exercise. The exercise program succeeded in stabilizing spinal BMD but had no effect on femoral BMD.

The effects of a community exercise program on fracture risk factors in older women

One hundred and seventy-nine women aged 60-85 years (mean age 71.6 years, SD 5.3 years) were randomly recruited from the community to participate in a 12-month randomized controlled trial to determine whether a program of twice-weekly structured exercise has beneficial effects on three factors associated with osteoporotic fractures: quadriceps strength, postural sway and bone density. At initial testing, there were no significant differences in the strength, sway and bone density measures (assessed at the hip and lumbar spine) between the exerciser and control groups. The exercise classes included strengthening, coordination and balance exercises, and approximately 35 min of each class comprised weight-bearing exercise. The mean number of classes attended for the 68 exercisers who completed the program was 59.8 of the 82 classes (72.9%). At the completion of the trial, the intervention group showed significant improvements in quadriceps strength and sway but not bone mineral density when compared with the control group. Indices of fracture risk, indicated by (i) the sum of standard score results and (ii) the sum of quartile grades of the femoral neck bone density, sway and strength measures, decreased significantly in the exercisers at the end of the trial compared with the controls. In conclusion, the program of general aerobic exercise may have reduced overall fracture risk, even though it did not significantly increase bone density. Further long-term studies are required that include acceptable weight-loaded exercises to determine optimal programs for reducing fracture risk factors by improving bone density as well as strength and balance.