Relationship Between Cognitive Performance, Physical Activity, and Socio-Demographic/Individual Characteristics Among Aging Americans.

BACKGROUND: Physical activity (PA) has emerged as a promising approach to delay Alzheimer's disease and related dementias, but the optimal intensity of PA to improve cognitive health remains unknown. OBJECTIVE: To evaluate the association between duration and intensity of PA and cognitive domains (executive function, processing speed, and memory) in aging Americans. METHODS: Linear regressions in hierarchical blocks for variable adjustment and the size of effect (η2) were analyzed by using the data of 2,377 adults (age = 69.3±6.7 years) from the NHANES 2011-2014. RESULTS: Participants with 3-6 h/week of vigorous- and > 1 h/week of moderate-intensity PA scored significantly higher in executive function and processing speed domains of cognition compared to inactive peers (η2 = 0.005 & 0.007 respectively, p < 0.05). After adjustment, the beneficial effects of 1-3 h /week of vigorous-intensity PA became trivial for delayed recall memory domain test scores (ß= 0.33; 95% CI: -0.01,0.67; η2 = 0.002; p = 0.56). There was no linear dose-response relationship between the cognitive test scores and weekly moderate-intensity of PA. Interestingly, higher handgrip strength and higher late-life body mass index were associated with a higher performance across all cognitive domains. CONCLUSION: Our study supports habitual PA with superior cognition health in some but not all domains among older adults. Furthermore, increased muscle strength and higher late-life adiposity may also impact cognition.

The impact of low-intensity blood flow restriction endurance training on aerobic capacity, hemodynamics, and arterial stiffness.

BACKGROUND: The aim of this study was to determine the effects of short-term low-intensity blood flow restriction (BFR) endurance training (ET) programs on measures of aerobic capacity, hemodynamics, and arterial stiffness in healthy young males. METHODS: Thirty-nine healthy young recreationally active males participated in this short-term training study. They were randomly assigned to a high-intensity (HI; N.=11; trained at 60-70% of VO2 reserve [VO2R]), low-intensity (LI; N.=8; trained at 30-40% of VO2R), low-intensity with BFR (LI-BFR; N.=10; trained at 30-40% of VO2R with BFR) or a non-exercising control group (N.=10). The exercising subjects completed a 6-wk training protocol on a treadmill. Assessment of aerobic capacity (VO2max), hemodynamics and arterial stiffness were done before and after training. RESULTS: Statistical analyses revealed a significant condition main effect (P<0.05) for VO2max, indicating significant increase (P<0.05) in VO2max in LI-BFR group compared to control. There were no significant changes for resting heart rate (RHR), systolic blood pressure (SBP), diastolic blood pressure (DBP), carotid-radial pulse wave velocity (PWV), and carotid-femoral PWV (P>0.05). However, femoral-tibial PWV decreased significantly (P<0.05) from baseline to post-training. CONCLUSIONS: The results indicate that the application of BFR during ET may cause faster and/or greater adaptations in one or more physiological systems resulting in improved cardiorespiratory fitness.

Aerobic training session length affects arterial elasticity.

PURPOSE: The purpose of this study was to examine haemodynamic and arterial elasticity responses to aerobic exercise of varying durations. METHODS: Eighteen male subjects (age = 23·4 ± 2·0) performed a maximal aerobic fitness (VO2max ) test. Participants met in the laboratory following an overnight fast for three randomly assigned sessions. Assessments for large and small arterial elasticity (SAE), systemic vascular resistance (SVR), total vascular impedance (TVI), systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), stroke volume (SV), cardiac output (CO), pulse pressure (PP) and cardiac ejection time (CET) were performed using applanation tonometry at the radial artery. Following baseline measurements, participants executed aerobic exercise on a treadmill at 65% of their respective VO2max for 30, 45 or 60 min on three different occasions. Postexercise measurements were performed immediately, 10, 20 and 40 min postexercise cessation. RESULTS: The 60-min exercise bout resulted in significantly increased SAE values (P < 0·04) and decreased SVR values (P < 0·02) when compared with the 30-min exercise bout. The 60-min session also caused significantly higher HR values and significantly lower values for SV and DBP values following exercise (P < 0·04). CONCLUSIONS: The results of this study emphasize that varying the length of moderate-intensity aerobic exercise bouts affects arterial elasticity response and total vascular resistance.

Small arteries stay stiff for a longer period following vibration exercises in combination with blood flow restriction.

PURPOSE: The aim of this study was to assess the effect of isometric exercises performed during whole-body vibration (WBV) with and without blood flow restriction (BFR) on arterial elasticity and hemodynamic variables. METHODS: Eight male subjects performed static upper body (UB) and lower body (LB) exercises on a vibration platform with and without BFR. During BFR sessions, BFR cuffs were placed on the arms or legs and inflated to a target pressure. Exercises consisted of eight 45-s sets for UB, and ten 1-min sets for LB. Arterial elasticity and hemodynamic variables were assessed before, at 10 min and 40 min postexercise. Repeated measures ANOVA was used to test the mean differences in related variables. RESULTS: A significant condition (BFR versus no-BFR) main effect was detected for small arterial elasticity (P<0·05). For heart rate (HR), there were significant time (P<0·01), condition (P = 0·02) and body (P = 0·04) main effects during exercise and condition (P<0·04) and time (P<0·01) main effects following exercise. Significantly lower values in systemic vascular resistance were detected at 10 min post compared to 40 min post (P<0·02) and UB compared to LB (P = 0·02). CONCLUSIONS: Results showed that small arteries stayed stiffer for a longer period of time after vibration exercises with BFR and BFR placed a greater demand on cardiovascular system. Findings also indicated that the type of exercises performed and/or the measurement location are very important and should be taken into account when examining arterial response.