The Acute Effects of 2 Different Intensities of Resistance Exercise on Autonomic Function in Heart Failure Patients: A Randomized Controlled Trial.

BACKGROUND: Although a wide spectrum of resistance exercise intensities was recommended in the guidelines, none of them investigated the acute effects of different intensities of the resistance exercise on cardiac autonomic function in patients with chronic heart failure. This study aimed to investigate the acute effects of the low and high intensities of the resistance exercise on heart rate variability in chronic heart failure. METHODS: This randomized controlled trial was performed between October 2019 and December 2020. Fifty-seven patients with chronic heart failure (New York Heart Association class II and class III) underwent hemodynamic, functional capacity, and heart rate variability (time and frequency domains) assessments. They were randomly divided into R1, R2, and control groups. The intervention consisted of performing a short aerobic exercise including 15 minutes of walking at an intensity of 50% reserved heart rate for all 3 groups and additional resistance exercise with the intensity of 50% 1-repetition maximum and 75% 1-repetition maximum for R1 and R2 groups, respectively. RESULTS: The standard deviation of normal to normal intervals and standard deviation of average NN intervals became significantly lower in R2 (P =.031), and both high-frequency power and low-frequency power were significantly higher in R1 (P =.039 and P =.004, respectively) after the intervention. No significant changes were observed in the control group. Between-group changes were not significant for hemodynamics and functional capacity after treatment. The between-group comparison demonstrated a significant increase in root mean square of successive differences of the NN intervals in R1 in comparison to the control (P =.035). CONCLUSIONS: These findings indicate that resistance exercise in 50% 1-repetition maximum in comparison to 75% 1-repetition maximum had more favorable effects on the heart rate variability in chronic heart failure.

Validation study of the Persian version of the subjective exercise experiences scale (SEES) in Iranian adult individuals.

BACKGROUND: Subjective exercise experiences scale (SEES) is a 12-item questionnaire assessing global psychological responses to exercise, with three constructs including positive well-Being (PWB), psychological distress (PD), and fatigue (FAT). The present study aimed to assess the reliability and validity of the SEES questionnaire in the Iranian population. METHOD: This cross-sectional psychometric study was conducted on 138 adults immediately after 30 min of walking. The internal consistency of the questionnaire was evaluated with Cronbach's alpha coefficient. To assess the test-retest reliability, 38 of the participants were requested to fill in the questionnaire again after a week. The test-retest reliability was analyzed using the intra-class correlation coefficient (ICC). The concurrent validity was examined through the correlation matrix between the domains of SEES and SF12. Principle component analysis was performed to determine the factor loading of the measured variables. IBM SPSS statistics 24 was used for all calculations. RESULTS: Cronbach's alpha was 0.82, 0.82, and 0.81 for the PWB, PD, and FAT, respectively. The ICC value was acceptable for all subscales (ICC for PWB, PD, and FAT were 0.83, 0.88, and 0.74 respectively). There was a weak to moderate correlation between the SEES and SF-12 subclasses. Factor analysis confirmed the three-factor structure of the instrument, explaining 67.21% of the observed variance. Item 3 didn't fit in well with the three constructs and was deleted from the Persian version of the SEES. CONCLUSIONS: The Persian version of the SEES is a valid and reliable instrument to evaluate the psychological response to the exercise stimulus.

Attention-demand effects on respiration in chronic low back pain patients.

Increasing attention is being drawn towards the involvement of systems other than the musculoskeletal one in the presence of low back pain (LBP). Recent evidence suggests both cognitive and respiratory functions to be affected in LBP patients. The aim of this study was to compare the effect of performance of a cognitive task on the respiratory function in LBP patients with that in control participants. Capnography and spirometry parameters of 48 participants (24 in each group) were assessed under 3 cognitive loading conditions (no, easy and difficult cognitive task). The results showed that in both groups the respiratory function was significantly affected by the introduction of the cognitive task (p < 0.05) and in the same manner (p > 0.05). Capnography and spirometry variables alterations were significantly correlated in the no-LBP group (p < 0.05) but there was no significant relationship between respiratory parameters and capnography and disability indices in the LBP group (p > 0.05). The findings of the current study suggest that while performing a cognitive task affects respiratory function, the possible differences of LBP patients and control participants may not be elicited under simple non-physically demanding postural conditions.

Effects of short-term aerobic exercise with and without external loading on bone metabolism and balance in postmenopausal women with osteoporosis.

The aim of this study is to evaluate the effect of submaximal aerobic exercise with and without external loading on bone metabolism and balance in postmenopausal women with osteoporosis (OP). Thirty-six volunteer, sedentary postmenopausal women with OP were randomly divided into three groups: aerobic, weighted vest, and control. Exercise for the aerobic group consisted of 18 sessions of submaximal treadmill walking, 30 min daily, 3 times a week. The exercise program for the weighted-vest group was identical to that of the aerobic group except that the subjects wore a weighted vest (4-8 % of body weight). Body composition, bone biomarkers, bone-specific alkaline phosphatase (BALP) and N-terminal telopeptide of type 1 collagen (NTX), and balance (near tandem stand, NTS, and star-excursion, SE) were measured before and after the 6-week exercise program. Fat decreased (p = 0.01) and fat-free mass increased (p = 0.005) significantly in the weighted-vest group. BALP increased and NTX decreased significantly in both exercise groups (p ≤ 0.05). After 6 weeks of exercise, NTS score increased in the exercise groups and decreased in the control group (aerobic: +49.68 %, weighted vest: +104.66 %, and control: -28.96 %). SE values for all directions increased significantly in the weighted-vest group. Results showed that the two exercise programs stimulate bone synthesis and decrease bone resorption in postmenopausal women with OP, but that exercise while wearing a weighted vest is better for improving balance.