Cortisol and physical performance in older populations: Findings from the international mobility in aging study (IMIAS)

Allostatic load and physical performance in older adults: Findings from the International Mobility in Aging Study (IMIAS)

OBJECTIVE

This study aimed to evaluate the association between Allostatic Load (AL) and physical performance scores in older adults from four cities in North and South America.

METHODS

In this cross-sectional study, data from 1101 volunteers from three countries (Canada, Brazil, and Colombia) from the International Mobility in Aging Study (IMIAS) were used to evaluate the association between AL index and Short Physical Performance Battery (SPPB) scores. Three multiple linear regression models adjusted by age, Socioeconomic Status (SES), chronic conditions, depression symptoms, and Leganés Cognitive Test (LCT) were developed to estimate the independent association between SPPB and AL. Mediation analysis with 2012 LA data and covariates was performed to access the total, direct, and indirect effects of mediation on SPPB scores from 2016.

RESULTS

AL and SPPB were inversely associated, with older adults with high allostatic load scoring lower on SPPB (β: -0.234, Std: 0.033, p-value: <0.001).  Indirect effects were evidenced between age, SES and chronic conditions with AL and SPPB scores. Chronic conditions also had a total effect on SPPB scores and were also mediated by AL. However, indirect effects of depressive symptoms and LCT on SPPB scores mediated by AL were not observed.

CONCLUSIONS

Findings from this study support that increased AL index determines worse physical performance states after full adjustments. AL has a mediator role between the number of chronic diseases, depressive symptoms, cognitive status and physical performance. Socioeconomic status also influenced physical scores mediated by the AL index.

Functional Limitations, Volunteering, and Diurnal Cortisol Patterns in Older Adults

OBJECTIVES

Older adults often experience functional limitations that affect their everyday lives, but many of them continue to make positive contributions to society and benefit from these contributions themselves. We examine (a) whether older adults' functional limitations are associated with diurnal cortisol patterns and (b) whether these associations vary on volunteering days versus nonvolunteering days.

METHODS

Participants were adults aged older than 60 years (N = 435) from the National Study of Daily Experiences, part of the Midlife in the United States Study. They completed an initial interview on functional limitations and background characteristics, indicated volunteering activities in daily interviews, and also provided salivary samples across 4 days.

RESULTS

Multilevel models showed that older adults with greater functional limitations exhibited dysregulated cortisol awakening responses and diurnal cortisol slopes throughout the rest of the day, compared to older adults with lower limitations. Yet, we also observed a significant moderating effect of volunteering on these associations.

DISCUSSION

This study advances our understanding of functional limitations and cortisol stress responses, revealing the benefits of volunteering to older adults who experience these limitations. Rather than treating these older adults solely as care recipients, interventions should offer them opportunities to help others.

Combined Chair-Based Exercises Improve Functional Fitness, Mental Well-Being, Salivary Steroid Balance, and Anti-microbial Activity in Pre-frail Older Women

Introduction

Regular exercise has long been shown to positively impact the immune system responsiveness and improve mental well-being (MWB). However, the putative links between biomarkers of mental health and immune efficiency in exercising subjects have been scarcely investigated. The aim of this study was to verify the effect of a 14-week combined chair-based exercise program (CEP) on salivary steroid hormones and anti-microbial proteins, functional fitness, and MWB indexes in pre-frail older women.

Methods

The participant women (82.8 4.6 years old; n = 32) were randomly divided into the exercising group (CEP, n = 17) and the non-exercising control group (CG, n = 15). The pre/post assessment included: (1) salivary anti-microbial proteins lysozyme; (Lys) and immunoglobulin-A (IgA); (2) salivary steroid hormones of testosterone (TT) and cortisol (COR); (3) functional fitness (gait speed, hand grip strength, and static balance); (4) MWB questionnaires (happiness, depression state, satisfaction with life, and stress).

Results

Significant differences with large Cohen's (d) effect sizes were found on increased salivary TT (p < 0.05; d = 0.60) after exercise intervention. The results revealed a decrease in IgA levels after CEP (p < 0.01, d = 0.30). The increase in subjective happiness levels (p < 0.05, d = 0.30) and decrease of stress perception (p < 0.01, d = 2.60) and depressive state (p < 0.05, d = 0.30) were found after intervention in the CEP group. Robust statistical differences in gait speed (p < 0.05; d = 0.60) and balance tests (p < 0.05; d = 0.80) were also found in the CEP group. In control, COR increased moderately (p < 0.05; d = 0.65) while no changes were found for the other indicators. Correlation analyses showed inter-dependence between pre-post variations of MWB, biochemical indexes, and fitness function (e.g., COR inverse correlation with hand grip strength and balance tests).

Conclusion

The CEP program was able to improve functional-fitness performance, decrease feelings of stress, and increase happiness. The CEP also induced clinically relevant hormonal and immune responses, which suggests that chair exercises that combine muscular strength, balance, and gait speed training are promising interventions to improve physical and mental health of older pre-frail adults.

Therapeutic implications of hypothalamic-pituitaryadrenal-axis modulation in Alzheimer's disease: A narrative review of pharmacological and lifestyle interventions

With disease-modifying treatments for Alzheimer's disease (AD) still elusive, the search for alternative intervention strategies has intensified. Growing evidence suggests that dysfunction in hypothalamic-pituitaryadrenal-axis (HPAA) activity may contribute to the development of AD pathology. The HPAA, may therefore offer a novel target for therapeutic action. This review summarises and critically evaluates animal and human studies investigating the effects of pharmacological and non-pharmacological intervention on HPAA modulation alongside cognitive performance. The interventions discussed include glucocorticoid receptor antagonists and 11β-hydroxysteroid dehydrogenase inhibitors as well as lifestyle treatments such as physical activity, diet, sleep and contemplative practices. Pharmacological HPAA modulators improve pathology and cognitive deficit in animal AD models, but human pharmacological trials are yet to provide definitive support for such benefits. Lifestyle interventions may offer promising strategies for HPAA modification and cognitive health, but several methodological caveats across these studies were identified. Directions for future research in AD studies are proposed.

Exercise, the diurnal cycle of cortisol and cognitive impairment in older adults

Exercise has been shown to reduce the risk of developing Mild Cognitive Impairment and Alzheimer's disease as well as to improve cognition in healthy and cognitively impaired individuals. However, the mechanisms of these benefits are not well understood. The stress hypothesis suggests that the cognitive benefits attributed to exercise may partially be mediated by changes in the cortisol secretion pattern. Chronic stress may increase the risk of AD and exacerbate the cognitive deficits and brain pathology characteristic of the condition while physical activity has been shown to attenuate most of stress consequences and risk factors for AD. Initially, research on the effects of cortisol on cognition and physical activity focused on cortisol levels at one time point but the circadian pattern of cortisol secretion is complex and it is still unclear which aspects are most closely associated with cognitive function. Thus, the aim of this review was to analyze the exercise/stress/cognition hypothesis focusing on the effects of the diurnal cycle of cortisol on cognitive function and physical activity in older adults with and without cognitive impairment.

Diurnal cortisol profiles, inflammation, and functional limitations in aging: Findings from the MIDUS study

OBJECTIVE

The current study examined the association between diurnal cortisol profiles, inflammation, and functional limitations, among adults ranging in age from 34-84 years.

METHOD

Participants (N = 799) completed Waves 2 (between 2004 and 2006) and 3 (between 2014 and 2016) of the Midlife Development in the United States Survey. At Wave 2, participants provided saliva samples across 4 consecutive days, from which cortisol was assayed. Previously validated diurnal cortisol profiles (i.e., normative, flattened, or elevated) were examined in relation to concurrent inflammation risk burden and to predict long-term changes in functional limitations.

RESULTS

Compared with participants with normative profiles across all interview days, participants with dysregulated profiles across all interview days (i.e., all days elevated, flattened, or a combination of elevated and flattened) showed greater concurrent inflammation risk burden and more functional limitations at follow-up. Regions of significance testing indicated that the association was significant beginning at age 60 for inflammation risk burden and beginning at age 66 for functional limitations. Variable profiles (i.e., a mix of normative and flattened and/or elevated across the four days of assessment) were not significantly associated with these health indices.

CONCLUSIONS

Findings, consistent with the theoretical model of Strength and Vulnerability Integration, illustrate the importance of considering age when examining cortisol and its association with other health indices. (PsycINFO Database Record

Association of activity status and patterns with salivary cortisol: the population-based CoLaus study

PURPOSE

Physical activity (PA) has been shown to influence salivary cortisol concentrations in small studies conducted among athletes. We assessed the association of activity status and patterns with salivary cortisol in the general population.

METHODS

Cross-sectional study including 1948 adults (54.9% women, 45-86 years). PA and sedentary behaviour (SB) were measured for 14 days by accelerometry. Low PA and high SB status were defined, respectively, as the lowest and highest tertile of each behaviour. 'Inactive', 'Weekend warrior', and 'Regularly active' patterns were also defined. Four salivary cortisol samples were collected over a single day and the following parameters were calculated: area under the curve to ground (AUCg), awakening response (CAR) and diurnal slope.

RESULTS

After multivariable adjustment, low SB remained associated to steeper slopes relative to high SB (- 1.54 ± 0.03 vs. - 1.44 ± 0.04 nmol/l per hour). Non-significant trends were found for high PA relative to low PA with steeper slopes (- 1.54 ± 0.03 vs. - 1.45 ± 0.04) and lower AUCg (208.7 ± 2.0 vs. 215.9 ± 2.9 nmol.h/l). Relative to 'Inactives', 'Regularly actives' had lower AUCg (205.4 ± 2.4 vs. 215.5 ± 2.9) and 'Weekend warriors' had steeper slopes (- 1.61 ± 0.05 vs. - 1.44 ± 0.04). No associations were found for CAR.

CONCLUSION

Low SB and high PA are related to lower cortisol secretion as measured by different parameters of salivary cortisol, but the effects were only modest.