Association between exercise type and quality of life in a community-dwelling older people: A cross-sectional study

Effects of Walking-Only Intervention on Physical Function, Fall-Related Outcomes, and Health-Related Quality of Life in Community-Dwelling Older Adults: A Systematic Review and Meta-Analysis

This study aimed to determine the effects of walking-only intervention (walking was the only exercise in which people participated) on physical function, fall-related outcomes, and health-related quality of life in community-dwelling older adults. We conducted a systematic search across five electronic databases, assessing risk of bias using Minds Manual for Guideline Development. Meta-analyses were performed, and pooled standardized mean differences were calculated. Nine studies (a total of 1,309 participants) were included, showing that walking-only interventions improved walking endurance (standardized mean difference: 1.11, 95% confidence interval: [0.08, 2.15]) and health-related quality of life (standardized mean difference: 0.71, 95% confidence interval: [0.18, 1.25]). However, there were no significant improvements in other outcomes. The certainty of the evidence based on the Grading of Recommendations, Assessment, Development, and Evaluation approach for all outcomes was graded as very low, primarily due to significant inconsistency and imprecision. Our results suggest that walking-only intervention can be effective for enhancing walking endurance and health-related quality of life for community-dwelling older adults. Further studies are required to investigate the effects of walking-only intervention. This need stems from the limited number of randomized controlled trials, heterogeneous intervention settings and results, and the very low certainty of the evidence.

Types of Home and Community-Based Physical Activity and Their Effects on the Older Adults' Quality of Life: A Systematic Review and Meta-Analysis

Home and community-based physical activity (HCBPA) has been extensively utilized among older adults. Nevertheless, the varying types of HCBPA, including different duration, intensity, and frequency, have sparked controversy regarding their impact on the quality of life in older adults. This study aims to explore the effects of HCBPA on QoL in older adults. We conducted a systematic review and retrieved studies published from January 2000 to April 2023 from multiple databases (PubMed, Embase, Cochrane, and the Web of Science Library). Seventeen articles met the inclusion criteria for this study. Long-term HCBPA interventions may have a more pronounced positive impact on older adults' quality of life than short-term ones, with the intervention's intensity and frequency playing a key role in its effectiveness. The results of the meta-analyses showed significant differences in PCS but not in MCS, both with low certainty of evidence. Policymakers should prioritize the importance of promoting HCBPA interventions with appropriate duration, intensity, and frequency to create a more age-inclusive society.

The association between physical activity and quality of life among people aged 60-89 living in own homes and nursing homes

BACKGROUND

The aim of the study was to obtain a response to the question of whether and how physical activity (PA) among people aged 60-89 years impacts quality of life and other sociodemographic characteristics (sex, age and place of living).

METHODS

Among 341 respondents aged 60 to 89, including 273 women (80%) and 68 men (20%) successfully completed IPAQ and WHOQOL AGE questionnaires. In the study were used International Physical Activity Questionnaire - IPAQ and World Health Organization Quality Of Life - Age - WHOQOL-AGE in Polish version.

RESULTS

The average total physical activity, including vigorous-intensity physical effort, moderate-intensity physical effort and walking amounts to 1381.87 ± 1978.60 MET-min/week. The average quality of life for the whole group of older people as evaluated with WHOQOL AGE scale was 64.79 (SD = 14.76; min:18.77-max: 98.07). Statistical analysis between physical activity and life quality proved significant dependence for the global life quality rating (p < 0.001).

CONCLUSIONS

Our research has shown that PA improves quality of life among older people. Higher scores of quality of life were obtained in the F1 subscale (satisfaction) than in the F2 subscale (meeting expectations) in both age groups. Age significantly affects quality of life for older people.

Effects of semi-immersive virtual reality exercise on the quality of life of community-dwelling older adults: Three-month follow-up of a randomized controlled trial

Objective

This study aimed to examine the effects of semi-immersive virtual reality (VR)-based exercise on the quality of life of older adults.

Methods

It used a randomized controlled trial design. Older adults (mean age: 72.16 ± 4.9 years) were randomly assigned to experimental (n = 48) and control (n = 50) groups. The experimental group engaged in semi-immersive VR exercise for 75-90 min, twice a week, for 12 weeks and partook in no other intervention between the end of the exercise intervention and follow-up. Control group members did not participate in any similar program during the intervention or follow-up periods. Both groups completed three assessments: at baseline (pre-test), post-intervention (post-test), and 3 months later (follow-up). Quality of life was assessed using the World Health Organization Quality of Life Instrument-Older Adults Module.

Results

Generalized estimating equation analyses indicated that the experimental group exhibited significant post-intervention improvements in quality of life in terms of sensory ability, autonomy, social participation/isolation, death and dying domain, and overall quality of life scores. However, none of these significant effects were maintained 3 months after exercise intervention cessation.

Conclusions

Semi-immersive VR exercise may be a feasible strategy toward enhancing the quality of life of older adults. However, the participants' quality of life was not maintained upon exercise cessation, indicating that older adults need to be encouraged to exercise regularly to maintain a good quality of life. VR may need to be combined with other modes of intervention in the future to facilitate long-term quality-of-life improvement in older adults.

Benefits of Cycling Wheelchair Training for Elderly with Physical Disability: A Prospective Cohort Study

AIM

In order to investigate the effect of cycling wheelchair training as an exercise for aged 65+ disabled patients on cognitive function, quality of life, aerobic capacity and physiological parameters.

METHODS

Participants in nursing home performed cycling wheelchair training for 30 min a day, 5 days a week, for a total of 4 weeks. The main outcome measure was the short form 12 survey (SF-12). Other outcome measures included the Mini-Mental State Examination (MMSE), aero bike work rate test, resting blood pressure, and heart rate.

RESULTS

In this study, 41 volunteers were recruited and no participants dropped out of the study voluntarily during training, and no serious adverse effect was identified. Physical and mental component summary total scores of SF-12 were significantly higher after training with statistical significance (p = 0.001). 8 subscales also showed significant improvements after training (p = 0.025 ~ <0.001). Total MMSE score has no difference before and after training. Attention/calculation (p = 0.018), short term memory (p = 0.041), and aerobic capacity (p < 0.001) as measured by subscales of MMSE and aero bike test showed marked improvements, while resting systolic blood pressure (p = 0.931) and heart rate (p = 0.793) did not change.

CONCLUSIONS

Cycling wheelchair is practical for the disabled elderly to exercise, and a 4-week exercise program enhanced their quality of life and aerobic capacity.

The effect of exercise on health-related quality of life in persons with musculoskeletal pain: A meta-analysis of randomised control trials

OBJECTIVES

Exercise has positive effects on musculoskeletal pain. In this project, the impact of exercise was studied on improving health-related quality of life in persons with musculoskeletal pain.

METHOD

The study design was a systematic review and meta-analysis. A search was conducted to find original studies in four sources, including PubMed, Web of Science, the Cochrane Library and Scopus, and this search was limited to the original articles published until April 2021, which were in English. For each study, the effect size was calculated. The analysis was based on the random-effects method.

RESULT

Twenty-Seven randomised control trial studies were included in the meta-analysis. The total population of participants in the meta-analysis was 1927 persons. Exercise improves health-related quality of life in these persons and the hedges' g was 0.66 (95% CI = 0.38-0.94; I²  = 88.29%).

DISCUSSION

Overall, based on the findings, exercise is associated with improving the health-related quality of life of persons with musculoskeletal pain, and therefore the health implications of this finding are beneficial to the general population and professionals.

Interactions between nutrient intake and comorbidities for quality of life in premenopausal and postmenopausal women

OBJECTIVE

This study aimed to identify the associations between nutrient intake and health-related quality of life (HRQOL) in premenopausal and postmenopausal women.

METHODS

Using data from Korean National Health and Nutrition Examination Surveys (2019-2020), EQ-5D-3L, and multivariate logistic and linear regression models, we analyzed the association and interaction between nutrient intake, comorbidities, and HRQOL among 4,027 Korean women.

RESULTS

Nutrient intake levels were lower in postmenopausal women than in premenopausal women. Interactions were observed between numerous nutrient intakes and comorbidities for HRQOL among premenopausal and postmenopausal women. Higher intakes of various nutrients (particularly, folic acid and vitamin A) were related to higher HRQOL scores in premenopausal women with comorbidities (log of inverse HRQOL scores, β = -0.31 [95% confidence interval [CI], -0.58 to -0.05] and β = -0.19 [95% CI, -0.37 to -0.001]) and postmenopausal women with comorbidities (log of inverse HRQOL scores, β = -0.34 [95% CI, -0.61 to -0.07] and β = -0.19 [95% CI, -0.38 to -0.01]), respectively. Regular exercise was associated with a lower risk of mobility problems (odds ratio [OR], 0.59; 95% CI, 0.44-0.81), self-care problems (OR, 0.53; 95% CI, 0.28-0.99), usual activity problems (OR, 0.42; 95% CI, 0.26-0.67), and any problem (OR, 0.71; 95% CI, 0.56-0.90), as well as an increase in HRQOL score (log of inverse HRQOL scores, β = -0.42; 95% CI, -0.68 to -0.16) in postmenopausal women. Smoking was related to a higher prevalence of depression and anxiety problems (OR, 2.51; 95% CI, 1.53-4.13) and any problem (OR, 1.67; 95% CI, 1.11-2.52), as well as a decrease in HRQOL scores (log of inverse HRQOL scores, β = 0.51; 95% CI, 0.14-0.88) in premenopausal women.

CONCLUSIONS

Given the lower nutrient intake levels in postmenopausal women, it is critical to establish HRQOL-improving approaches for this population, including regular exercise, nutrient intake, and smoking cessation.

Association of physical fitness with quality of life in community-dwelling older adults aged 80 and over in Poland: a cross-sectional study

Background

Aging is a progressive and irreversible process that negatively affects the quality of life (QOL). Older adults face difficulties related to worsening health, lowering the level of physical and mental efficiency. We aimed to analyze the associations between physical fitness and QOL in Polish older adults considering sex differences.

Methods

This cross-sectional study was performed from March to August 2015. The sample consisted of 100 community-dwelling adults (67 women, 33 men) with a mean age of 82.94 ± 2.67 years. The World Health Organization QOL, Short Form questionnaire (WHOQOL-BREF), and the Fullerton Functional Fitness Test (FFFT) were used. Biometric data, social and environmental situation, nutritional and lifestyle behaviors have been also collected using a questionnaire designed by the authors.

Results

The results obtained in individual domains of WHOWOL-BREF indicate a good level of QOL in all the examined domains. Statistically significant sex differences were obtained in physical (p = 0.01), psychological (p = 0.04) and environmental (p = 0.02) domains in WHOQOL-BREF. It was noted that men perform better in terms of the upper (arm curl, p < 0.001) and lower body strength (chair stand, p = 0.01), aerobic endurance (two-minute step test, p < 0.001), agility and dynamic balance (up and go test, p < 0.001) in FFFT.

Conclusions

Community-dwelling older adults aged 80–93 years in Poland present a good level of QOL, and the higher score was obtained in men. Also, men presented better physical fitness, showed a higher level of independence in daily activities, and assessed better their own QOL than women.

Effects of resistance bands exercise for frail older adults: A systematic review and meta-analysis of randomised controlled studies

AIMS AND OBJECTIVES

Research examining the effectiveness of resistance band exercises for improving physical and psychological dimensions among frail older adults has been inconsistent. We aimed to examine the effects of resistance band exercises for improving outcomes in frail older adults.

BACKGROUND

To provide robust evidence regarding the effectiveness of resistance band exercises and explore other potential outcomes in frail older adults, a systematic review of RCTs remains necessary.

DESIGN

Systematic literature review and meta-analysis were conducted in accordance with the PRISMA guidelines.

METHODS

Four databases were searched. English language papers were retrieved from 2006 to 2020. Three reviewers reviewed the methodology of the selected studies using the Joanna Briggs Institute tool for randomised controlled trials. The pooled standardised mean difference was calculated using a random-effects model. Heterogeneity among pooled studies was assessed using the τ² , Q and I² statistics, and publication bias was evaluated using Egger's test and the visual inspection of funnel plots.

RESULTS

A total of 15 studies met the eligibility criteria for this study. Overall, resistance band exercise reduced frailty after 24 weeks (SMD: -0.29; 95% CI: -0.55 to -0.03) and reduced depression after both 12 weeks (SMD: -0.19; 95% CI: -0.38 to -0.01) and 24 weeks (SMD: -0.30; 95% CI: -0.52 to -0.09). However, no significant effects were observed for frailty after 12 weeks, and no significant effects were observed for grip strength, leg strength, activities of daily living or quality of life at any time.

CONCLUSION

Resistance band exercise might be considered a viable strategy for frail older adults in the community or in long-term care facilities. More research implementing a standardised protocol remains necessary to identify the effects of different training volumes and the dose-response relationship for the very old and frail population.

RELEVANCE TO CLINICAL PRACTICE

As a safe complementary intervention for frail older adults, health providers should consider resistance band exercises when caring for frail older adults because this intervention has clinical benefits.

Assessment of muscle-strengthening exercise in public health surveillance for adults: A systematic review

There is strong scientific evidence that muscle-strengthening exercise (i.e. use of weight machines, push-ups, sit-ups) is independently associated with a reduced risk of multiple chronic diseases (e.g. diabetes, hypertension, cardiovascular disease). However, prevalence rates for meeting the muscle-strengthening exercise guideline (≥2 times/week) are significantly lower (~20%) than those reported to meet the aerobic physical activity guideline (e.g. walking, jogging, cycling) (~50%). It is therefore important to understand public health surveillance approaches to assess muscle-strengthening exercise. The aim of this review was to describe muscle-strengthening exercise assessment in public health surveillance. Informed by the PRISMA guidelines, an extensive keyword search was undertaken across 7 electronic data bases. We identified 86,672 possible articles and following screening (n = 1140 in full-text) against specific inclusion criteria (adults aged ≥18 years, English, studies containing <1000 participants), extracted data from 156 manuscripts. Fifty-eight different survey systems were identified across 17 countries. Muscle-strengthening exercise frequency (85.3%), duration (23.7%) and intensity (1.3%) were recorded. Muscle-strengthening exercise questions varied significantly, with some (11.5%) requiring a singular 'yes' vs 'no' response, while others (7.7%) sought specific details (e.g. muscle groups targeted). Assessments of duration and intensity were inconsistent. Very few studies measured the validity (0.6%) and reliability (1.3%) of muscle-strengthening exercise questions. Discrepancy exists within the current assessment systems/surveys used to assess muscle-strengthening exercise in public health surveillance. This is likely to impede efforts to identify at risk groups and trends within physical activity surveillance, and to accurately assess associations between muscle-strengthening exercise and health-related outcomes.

Effects of 24 weeks strength training with and without unstable devices on strength, flexibility and quality of life in older women: A secondary analysis from randomized controlled trial

BACKGROUND: Combining strength training (ST) with unstable surfaces (US) is a promising complementary approach to traditional ST to optimize muscle strength and balance in different populations. OBJECTIVE: To evaluate the effects of traditional ST and ST+US on grip strength, flexibility and quality of life in older women. METHODS: Fifty-eight older women were randomly assigned into ST (n= 22), ST+US (n= 22) or control (n= 14) group. Exercise groups performed whole-body, moderate-intensity strength exercises, thrice a week during 24-weeks. ST+US participants performed the same exercise prescription progressively adding unstable surfaces and devices. Dependent variables (grip strength, flexibility and health-related quality of life) were measured at baseline, 12-weeks and after 24-weeks of intervention. RESULTS: At completion of 24-weeks, compared with control group, traditional ST promote flexibility gains [SRT =+ 5.42 cm (95% CI = 1.01 to 9.83)]. Both training regimes improved quality of life [ST =+9.50 (95% CI = 1.80 to 17.20); ST+US =+ 15.23 (95%CI = 7.37 to 23.08). No significant between-group difference was observed for grip strength at completion of the intervention. CONCLUSION: Traditional strength exercises were effective to improve flexibility and health-related quality of life among healthy older women. Combining unstable devices with traditional exercise did not provide additional gains in order to promote flexibility and quality of life.

Life Satisfaction, Positive Affect, and Sleep Impairment in Masters Athletes: Modulation by Age, Sex, and Exercise Type

Introduction

The masters athlete has been proposed as a model of successful aging. Research studies investigating psychological outlook in older athletes have primarily addressed negative affects including depression, anxiety, and stress. The impact of lifelong exercise on positive affect and life satisfaction as well as sleep impairment that could impact on these psychological states is largely unknown.

Methods

A series of questionnaires (general life satisfaction, positive affect, and sleep-related impairment) were administered to 240 masters athletes participating in the World Masters Athletics Championships. Total raw scores were converted into T scores for comparison with the general population. Meaningful difference was defined by the PROMIS^® as one-half standard deviation from the centering sample.

Results

Meaningful differences were observed for improved general life satisfaction and reduced sleep impairment for all masters athletes. Positive affect did not reach the meaningful difference threshold. No significant sex differences were found for any of the questionnaires (all p > 0.05). Similarly, no significant differences were found between endurance, sprint, and strength/power sports for general life satisfaction (p = 0.18), positive affect (p = 0.46), and sleep impairment (p = 0.77). In general, life satisfaction increased with age (r = 0.15, p = 0.02), and sleep impairment trended towards reduction with age (r = −0.13, p = 0.05). Positive affect demonstrated no correlation with age (r = 0.09, p = 0.18).

Conclusion

This study demonstrates that the lifestyles of masters athletes contribute to improved general life satisfaction and reduced sleep impairment but not improved positive affect. The beneficial effects were observed irrespective of age, gender, and sporting types.

The Exploration of Occupational Therapy Interventions to Address Sedentary Behavior and Pain Among Older Adults

This study aimed to determine the feasibility of an occupational therapy intervention to address sedentary behavior and pain among older adults residing in assisted living facilities. A single group pretest and posttest design was implemented using the Sedentary Behavior Questionnaire, actigraphy technology, and daily activity logs to measure sedentary behavior. The Short-Form McGill Pain Questionnaire was used to assess pain. Occupational therapy intervention focused on individualized goals related to participation in meaningful physical activities, which were established in collaboration with the participant and were tracked for 3 weeks. A total of 12 participants were recruited for this study. The mean number of steps and daily calories burned over the course of a week increased by 3,058.3 steps (30.82%) and 57.64 calories (19.96%), respectively. Individualized goal setting may have a positive impact on the reduction of pain and increasing activity levels among older adults residing in assisted living facilities.

Effects of starting position, distance and ending point in a walking speed test among older adults

AIMS

This study examined the effects of the starting position, distance and ending point on walking speed in older adults with both the usual and maximum walking speeds.

METHODS

In total, 101 older community-dwellers aged between 60 and 74 years were included in this cross-sectional study. Participants were instructed to walk two distances (i.e., 10 and 25 m) at usual and maximum speeds twice. The paired t-test was used to examine the effects of starting positions (static start vs. dynamic start) and ending points (known vs. unknown ending point) on walking speed. Analysis of variance was used to explore walking speed differences among 4, 6, 8, 10, 15, 20 and 25 m walking tests.

RESULTS

Differences in walking speed between static start and dynamic start became larger with a decrease in the walking distance (Cohen's d: 4 m > 6 m > 10 m), and differences were larger in tests at the maximum walking speed (Cohen's d = 0.28-0.85) compared with those at usual walking speed (Cohen's d = 0.21-0.67). The walking speed increased with distance, but no significant changes were found among 10, 15, 20 and 25 m tests at the usual speed. Trivial speed differences were observed in walking speed between known (mean = 1.23-1.82 m/s) and unknown ending points (mean = 1.27-1.86 m/s; Cohen's d < 0.20).

CONCLUSIONS

Test parameters, particularly the starting position and walk distance, do influence walking speed measured in the short-distance walking speed test among older adults. Geriatr Gerontol Int ••; ••: ••-•• Geriatr Gerontol Int 2020; ••: ••-••.

Association between type of exercise and health-related quality of life in adults without activity limitations: a nationwide cross-sectional study

BACKGROUND

Exercise is known to be associated with health-related quality of life (HRQoL), however, evidence on the association between type of exercise and HRQoL in the general population is limited. We performed this study to investigate the association of exercise types and their combinations with HRQoL in Korean adults.

METHODS

We analyzed data from 13,437 adults aged ≥19 years without activity limitations who had participated in the 5th Korea National Health and Nutrition Examination Survey 2010-2012. As per the American College of Sports Medicine guideline, exercise types were categorized into eight groups: walking (W), flexibility (F), resistance (R), W + F, W + R, F + R, and W + F + R exercise groups and a non-exercise group. The European Quality of Life-5 Dimension (EQ-5D) index and the European Quality of Life Visual Analogue Scale (EQ-VAS) were used to assess HRQoL.

RESULTS

The mean age of participants was 42.8 ± 0.2 years. The proportion of participants in the non-exercise group was the highest (34.7%); among the exercise groups, the walking group was the most prevalent (16.9%) and the W + R group was the least (1.2%). In analysis of covariance, the mean EQ-5D index in W (0.875), W + F (0.878), F + R (0.877), and W + F + R (0.876) groups was significantly higher compared with that in non-exerciser group (0.869) (p < 0.05). The mean EQ-VAS score in the W (64.064), F (64.427), W + F (65.676), F + R (65.811), and W + F + R (67.110) groups was higher than that in the non-exercise group (62.396) (p < 0.05). No difference was observed between R and W + R groups and non-exercise group with regard to the EQ-5D index and EQ-VAS score.

CONCLUSIONS

The W (for 30 min at least five times a week), W + F, F + R (at least two days a week), and W + F + R groups showed higher HRQoL than the non-exercise group. This study may be helpful in the development of public exercise interventions, which could help enhance HRQoL in adults.

Association between muscle strength and health-related quality of life in a Chinese rural elderly population: a cross-sectional study

OBJECTIVE

To investigate the relationship between upper and lower limb muscle strength and the health-related quality of life (HRQoL) of a Chinese rural, elderly population.

DESIGN

A population-based, cross-sectional study.

SETTING

Miyun, Beijing, China.

PARTICIPANTS

The participants of this study were 2083 (834 men and 1249 women) older adults from a rural area, (average age of ≥60 years), living in Miyun county, located on the outskirts of Beijing. Data were collected between May and October 2014. Handgrip strength and timed up and go tests (TUGT) were conducted to measure the muscle strength of their upper and lower limbs, respectively. The Euro Quality of Life (Euroqol) (EQ-5D)-Visual Analogue Scale was used to evaluate participants' HRQoL.

RESULTS

A significant association between handgrip strength and the EQ-5D index (β=0.015 per SD, 95% CI: 0.008 to 0.023, p<0.001) was discovered, following adjustments. The association between handgrip strength and the EQ-5D index in the ≥80 years group was found to be stronger than that of the 60-79 years group, following adjustment (β per SD: 0.013 vs 0.035). Similar results were observed when comparing the non-chronic disease group, in terms of TUGT time, against those with chronic diseases.

CONCLUSIONS

There was a significant relationship between muscle strength (measured via handgrip strength and TUGT time) and HRQoL (measured via EQ-5D index and VAS score) in the Chinese rural elderly population. Furthermore, this relationship was stronger in the older population (aged ≥80 years), and in those participants diagnosed with chronic diseases.

Regular exercise and the trajectory of health-related quality of life among Taiwanese adults: a cohort study analysis 2006-2014

Background

Physical activity is related to health-related quality of life, but little evidence from multiple waves of panel data in Asian countries area available. This study aims to explore the impacts of different degree of regular exercise on the trajectories of physical and mental dimensions of health-related quality of life (HRQOL) for community-dwelling Taiwanese adults during 2006–2014.

Methods

Data were derived from the “Landseed Integrated Outreaching Neighborhood Screening (LIONS)” study, with 6182 adults enrolled at the baseline and subsequently followed up to three times till 2014. Linear mixed-effects modeling approach was employed to evaluate the growth curve models of HRQOL (with 16,281 observations) by linear & quadratic time effects, regular exercise (5-level moderate-intensity physical activity), and major influential factors of HRQOL.

Results

Regular exercise showed significantly positive dose-response effects on physical HRQOL (β =1.27~2.54), and regular exercise of 150 min or more showed positive effects on mental HRQOL (β = 1.55~2.03). Besides, irregular exercise could also improve both physical and mental HRQOL (β = 1.27 & β = 0.87). However, such effects were not significant over time (at time slope) on HRQOL. In addition, physical and mental HRQOL improved across time (β = 1.01 and 1.49, respectively), but the time quadratic effect would significantly offset a little bit on physical dimension (β = − 0.22). Moreover, being female, increasing age, living alone, or poorer health status were related to lower physical HRQOL; and being younger, living alone, or poorer health status were associated with lower mental HRQOL.

Conclusions

The positive dose-response relationship between regular exercise and HRQOL or its domains was demonstrated for community-dwelling Taiwanese adults. Thus, a regular exercise habit (better ≧150 min per week) is advised for community-based healthcare professionals and the government to incorporate into health promotion strategies and plans.

Functions of estrogen and estrogen receptor signaling on skeletal muscle

Activity of estrogen, a sex steroid hormone, is not only limited to the reproductive organs but also involves other organs and tissues, including skeletal muscle. In postmenopausal women, estrogen decline causes endocrine and metabolic dysfunction, leading to a predisposition to osteoporosis, metabolic syndrome, and decreased muscle mass and strength. The decline in skeletal muscle mass often associates with sarcopenia, a popular condition observed in fragile elder people. In addition, varying estrogen levels associated with the menstrual phases may modulate exercise performance in women. Estrogen is thus considered to play a crucial role in skeletal muscle homeostasis and exercise capacity, although its precise mechanisms remain to be elucidated. In this article, we review the role of estrogen in the skeletal muscle, outlining the proposed molecular mechanisms. We especially focus on the current understanding of estrogen actions on mitochondria metabolism in skeletal muscle.