Associations between muscular strength and mental health in cognitively normal older adults: a cross-sectional study from the AGUEDA trial

Objective

To examine the associations between muscular strength and mental health.

Design

We used baseline data of 91 cognitively healthy older adults (71.69 ± 3.91 years old, 57 % women) participating in the AGUEDA randomized controlled trial.

Methods

Muscular strength was assessed using both objective (i.e., handgrip strength, biceps curl, squats, and isokinetic test) and perceived (i.e., International Fitness Scale) indicators. Psychological ill-being indicators: anxiety, depression, stress, and loneliness; and psychological well-being indicators: satisfaction with life, self-esteem, and emotional well-being) were assessed using a set of valid and reliable self-reported questionnaires. Linear regression analyses were performed adjusting for sex, age, years of education, body mass index , alcohol, diet, and smoking (model 1), and additionally by cardiorespiratory fitness (model 2).

Results

Elbow extension was positively associated with stress in model 1 (β = 0.252, 95 % Confidence Interval [95 % CI] = 0.007 to 0.497, p = 0.044), and even after further adjustment for cardiorespiratory fitness (β = 0.282, 95 % CI = 0.032 to 0.532, p = 0.028). Perceived strength was negatively associated with depressive symptoms in model 1 (β = -0.271, 95 % CI = -0.491 to -0.049, p = 0.017) and model 2 reported associations tending towards significant (β = -0.220, 95 % CI = -0.445 to 0.005, p = 0.055). Handgrip strength was positively associated with self-esteem in model 1 (β = 0.558, 95 % CI = 0.168 to 0.949, p = 0.006) and model 2 (β = 0.546, 95 % CI = 0.135 to 0.956, p = 0.010). No further associations were found among other muscular strength and mental health variables.

Conclusion

Handgrip had a moderate association with self-esteem and there was a small association between perceived strength with depressive symptoms and elbow extension with stress. No other associations were observed between muscular strength and mental health outcomes in cognitively normal older adults.

Association of muscular strength and targeted proteomics involved in brain health in children with overweight/obesity

Muscular strength has been positively associated with better brain health indicators during childhood obesity. However, the molecular mechanisms underlying the positive impact of muscular strength in brain health are poorly understood. We aimed to study the association of muscular strength with neurology-related circulating proteins in plasma in children with overweight/obesity and to explore the role of cardiorespiratory fitness (CRF) as a confounder. The participants were 86 Caucasian children (10.1 ± 1.1 years old; 41% girls) from the ActiveBrains project. Muscular strength was measured by field and laboratory tests. CRF was assessed with an incremental treadmill test. Olink's technology was used to quantify 92 neurology-related proteins in plasma. Protein-protein interactions were computed using the STRING website. Muscular strength was positively associated with 12 proteins (BetaNGF, CDH6, CLEC10A, CLM1, FcRL2, HAGH, IL12, LAIR2, MSR1, SCARB2, SMOC2, and TNFRSF12A), and negatively associated with 12 proteins (CLEC1B, CTSC, CTSS, gal-8, GCP5, NAAA, NrCAM, NTRK2, PLXNB3, RSPO1, sFRP3, and THY1). After adjustment for CRF, muscular strength was positively associated with eight proteins (BetaNGF, CDH6, CLEC10A, FcRL2, LAIR2, MSR1, SCARB2, and TNFRSF12A) and negatively associated with two proteins (gal-8 and NrCAM). After applying FDR correction, only CLEC10A remained statistically significant. In conclusion, muscular strength was associated with blood circulating proteins involved in several biological processes, particularly anti-inflammatory response, lipid metabolism, beta amyloid clearance, and neuronal action potential propagation. More powered studies are warranted in pediatric populations to contrast or confirm our findings.

Active Gains in brain Using Exercise During Aging (AGUEDA): protocol for a randomized controlled trial

Alzheimer's disease is currently the leading cause of dementia and one of the most expensive, lethal and severe diseases worldwide. Age-related decline in executive function is widespread and plays a key role in subsequent dementia risk. Physical exercise has been proposed as one of the leading non-pharmaceutical approaches to improve executive function and ameliorate cognitive decline. This single-site, two-arm, single-blinded, randomized controlled trial (RCT) will include 90 cognitively normal older adults, aged 65-80 years old. Participants will be randomized to a 24-week resistance exercise program (3 sessions/week, 60 min/session, n = 45), or a wait-list control group (n = 45) which will be asked to maintain their usual lifestyle. All study outcomes will be assessed at baseline and at 24-weeks after the exercise program, with a subset of selected outcomes assessed at 12-weeks. The primary outcome will be indicated by the change in an executive function composite score assessed with a comprehensive neuropsychological battery and the National Institutes of Health Toolbox Cognition Battery. Secondary outcomes will include changes in brain structure and function and amyloid deposition, other cognitive outcomes, and changes in molecular biomarkers assessed in blood, saliva, and fecal samples, physical function, muscular strength, body composition, mental health, and psychosocial parameters. We expect that the resistance exercise program will have positive effects on executive function and related brain structure and function, and will help to understand the molecular, structural, functional, and psychosocial mechanisms involved.

Resistance Exercise Program in Cognitively Normal Older Adults: CERT-Based Exercise Protocol of the AGUEDA Randomized Controlled Trial

OBJECTIVES

To provide a comprehensive CERT (Consensus on Exercise Reporting Template)-based description of the resistance exercise program implemented in the AGUEDA (Active Gains in brain Using Exercise During Aging) study, a randomized controlled trial investigating the effects of a 24-week supervised resistance exercise program on executive function and related brain structure and function in cognitively normal older adults.

DESIGN AND PARTICIPANTS

90 cognitively normal older adults aged 65 to 80 were randomized (1:1) to a: 1) resistance exercise group; or a 2) wait-list control group. Participants in the exercise group (n = 46) performed 180 min/week of resistance exercise (3 supervised sessions per week, 60 min/session) for 24 weeks.

INTERVENTION

The exercise program consisted of a combination of upper and lower limb exercises using elastic bands and the participant's own body weight as the main resistance. The load and intensity were based on the resistance of the elastic bands (7 resistances), number of repetitions (individualized), motor complexity of exercises (3 levels), sets and rest (3 sets/60 sec rest), execution time (40-60 sec) and velocity (as fast as possible).

SETTINGS

The maximum prescribed-target intensity was 70-80% of the participants' maximum rate of perceived exertion (7-8 RPE). Heart rate, sleep quality and feeling scale were recorded during all exercise sessions. Those in the wait-list control group (n = 44) were asked to maintain their usual lifestyle. The feasibility of AGUEDA project was evaluated by retention, adherence, adverse events and cost estimation on the exercise program.

RESULTS AND CONCLUSIONS

This study details the exercise program of the AGUEDA trial, including well-described multi-language manuals and videos, which can be used by public health professionals, or general public who wish to implement a feasible and low-cost resistance exercise program. The AGUEDA exercise program seems to be feasible by the high retention (95.6%) and attendance rate (85.7%), very low serious adverse event (1%) and low economic cost (144.23 € /participant/24 weeks). We predict that a 24-week resistance exercise program will have positive effects on brain health in cognitively normal older adults.