Favorable effect of sympathetic nervous activity on rehabilitation outcomes in frail elderly

Plasma Leptin Concentration and Sympathetic Nervous Activity in Older Adults With Physical Dysfunction

Context

Previous research has shown a positive relationship between plasma leptin and sympathetic nervous activity. High plasma leptin activate inflammatory cytokines and lead to muscle wasting. However, studies have detected low sympathetic nervous activity and high plasma leptin in older adults with muscle wasting, sarcopenia, and frailty. High plasma leptin do not seem to correlate with high sympathetic nervous activity. However, their relationship in older adults remains unclear.

Objective

We investigated the relationship between plasma leptin and sympathetic nervous activity in older adults.

Design, Setting, and Participants

We conducted a cross-sectional study and analyzed the results from 69 participants aged ≥75 years. Sympathetic nervous activity was measured by heart rate variability, obtained from 24-hour Holter monitoring. A functional independence measure (FIM) and Barthel index were used to assess physical function.

Results

The plasma leptin was higher in women (men, 3.4 ± 2.8 ng/mL; women, 6.6 ± 6.5 ng/mL; P = 0.024). Plasma leptin was negatively and substantially related to the FIM (β = −0.233; P = 0.049) and Barthel index (β = −0.298, P = 0.018) after adjustment for covariates. However, the data showed no relationship between the plasma leptin and sympathetic nervous activity.

Conclusions

We could not detect an association between sympathetic nervous activity and plasma leptin in older adults. This might suggest a failure of the feedback system of the sympathetic nervous system, leading to muscle wasting in older adults.

Role of autonomic nervous activity, as measured by heart rate variability, on the effect of mortality in disabled older adults with low blood pressure in long-term care

AIM

Previous studies have shown the relationship between low blood pressure and high mortality in frail, disabled older adults in long-term care. However, the mechanism of this relationship is still unclear. We hypothesized that autonomic nervous activity decline is involved in the relationship between low blood pressure and high mortality.

METHODS

The present prospective cohort study recruited 61 participants aged ≥75 years. The data from 24-h Holter monitoring and blood pressure recorded by ambulatory blood pressure monitoring were collected. Measured data were divided into three categories: 24-h, daytime and night-time. From power spectral density in the electrocardiogram, low frequency, high frequency and low frequency/high frequency ratio were calculated. The primary end-point was death.

RESULTS

High blood pressure was connected to both high daytime low frequency and high frequency (partial correlation coefficients: 0.42, P < 0.05 and 0.35, P < 0.05, respectively). In addition, the low blood pressure group had higher mortality than the high blood pressure group, and disabled older adults in long-term care and those with elevated daytime systolic and diastolic blood pressure had less risk of mortality compared with those without (systolic: hazard ratio 0.89, 95% confidence interval 0.83-0.96, P = 0.003; diastolic: hazard ratio 0.98, 95% confidence interval 0.79-1.00, P = 0.049). The average blood pressures in the high blood pressure groups were approximately 140/80 mmHg and were connected to low mortality.

CONCLUSIONS

Attenuated autonomic nervous activity might lead to low blood pressure in the daytime and high mortality in disabled older adults in long-term care. Geriatr Gerontol Int 2018; 18: 1153-1158.

An experiment to classify the clinical fear seen during aerobic movement acquisition in adults with visual impairment

[Purpose] This study aimed to classify the fear that occurs during the process of a squat-like movement by persons with visual impairment. [Subjects and Methods] Fifteen persons with a visual impairment, 45 years and older, who were independent in daily living were recruited for the study. The study utilized a field experiment design. The setting was the Kusatsumachi Welfare Center, and the study period was from March through August 2015. Outcome measures included the presence or absence of fear during attempt of a squat-like movement on a force plate. Metrics included the ratio of low and high frequency components of heart rate variability spectra (cm²/Hz) based on resting rate intervals (ActiGraph wGT3X-BT, USA). Autonomic hyperactivity was defined as the occurrence of objective fear with LF/HF ratio of over 2.0. Statistics included Fischer’s exact test. [Results] Four fear types included the combination of danger and objective fear factors. The frequencies of occurrence of clinically categorized subjective fear across the four fear types were two (danger, fear), seven (no danger, fear), six (danger, no fear), and zero (no danger, no fear) persons. [Conclusion] This procedure of classifying fear might be feasible during evaluation of a squat-like movement by persons with a visual impairment.