This study examined the effect of an exercise intervention on the composition of the intestinal microbiota in healthy elderly women. Thirty-two sedentary women that were aged 65 years and older participated in a 12-week, non-randomized comparative trial. The subjects were allocated to two groups receiving different exercise interventions, trunk muscle training (TM), or aerobic exercise training (AE). AE included brisk walking, i.e., at an intensity of ≥ 3 metabolic equivalents (METs). The composition of the intestinal microbiota in fecal samples was determined before and after the training period. We also assessed the daily physical activity using an accelerometer, trunk muscle strength by the modified Kraus–Weber (K-W) test, and cardiorespiratory fitness by a 6-min. walk test (6MWT). K-W test scores and distance achieved during the 6MWT (6MWD) improved in both groups. The relative abundance of intestinal Bacteroides only significantly increased in the AE group, particularly in subjects showing increases in the time spent in brisk walking. Overall, the increases in intestinal Bacteroides following the exercise intervention were associated with increases in 6MWD. In conclusion, aerobic exercise training that targets an increase of the time spent in brisk walking may increase intestinal Bacteroides in association with improved cardiorespiratory fitness in healthy elderly women.

We aimed to examine the effect of 2-year cognitive–motor dual-task (DT) training on cognitive functions and motor ability of healthy elderly people without marked cognitive impairment. From the 25 participants of our 12-week DT trial conducted in 2014, we recruited 8 subjects who voluntarily participated in a new DT training program once a week for 2 years (exercise (EX) group). Their cognitive functions were evaluated by the Modified Mini-Mental State (3MS) examination and the Trail Making Test, and results were compared with those of the 11 subjects who discontinued the training and did not perform any types of exercise for 2 years (non-exercise (NO) group). Subjects in the NO group showed deterioration in the 3MS examination results, especially in the cognitive domain of attention. Meanwhile, participation in DT training maintained the scores in almost all domains of cognitive function, as well as the total 3MS scores. However, both groups had impaired quadriceps muscle strength and motor ability after the 2-year observation period. These results suggest that participating in exercise program comprising DT training for 2 years may be beneficial for maintaining the broad domains of cognitive function in healthy elderly people, although further verification is needed.

Introduction: In this study, we aimed to investigate the effect of daily physical activity levels, specifically brisk walking, on short-chain fatty acid (SCFA) production through the modulation of SCFA-producing bacteria in young individuals. Methods: This 12-week randomized comparative trial included 30 participants. The participants were assigned to either the group that walked 8000 steps daily, including 20 minutes of brisk walking at an intensity of≥5 metabolic equivalents (BW group), or the group that walked 8000 steps daily at their customary pace (CP group). The SCFA levels and composition of the intestinal microbiota were assessed before and after the intervention. Daily physical activity and cardiorespiratory fitness were monitored using an accelerometer and the incremental shuttle walking test (ISWT), respectively. Results: The BW group exhibited a significant increase in the level of acetic acid, a type of SCFA, following the intervention. The relative abundance of intestinal Bifidobacterium was significantly higher in participants who successfully completed 20 minutes of brisk walking during the intervention. Conclusion: Daily brisk walking for 20 minutes enhances acetic acid production by fostering the proliferation of Bifidobacterium in young individuals.

It remains unknown whether the high insulin (INS) levels in the brain affect fat oxidation during exercise. We examined the effects of the intranasal administration of INS, which increases the INS concentration in the cerebrospinal fluid when peripheral effects are lacking, on the maximum fat oxidation rate (maxFOR) and its intensity (FATmax) during exercise in 15 young normal-weight (N group) and eight young overweight (O group) individuals. On two separate days, either INS or placebo (PL) was randomly administered intranasally before a graded exercise test. Indirect calorimetry was used to assess maxFOR and FATmax during exercise. Blood INS and glucose levels did not change after INS administration. In the N group, maxFOR and FATmax were significantly smaller in the INS trial than in the PL trial. MaxFOR was significantly smaller in the O group than in the N group and was not influenced by INS administration. Exercise-induced elevation in blood epinephrine levels tended to be reduced by INS administration only in the N group. Intranasal INS administration reduces fat oxidation during exercise without any peripheral effects, possibly by suppressing sympathetic nerve activity. This inhibitory effect is diminished in overweight subjects, suggesting that cerebral insulin effects are attenuated in this population.

Purpose: Fragrance inhalation of essential oils used in aromatherapy can affect blood pressure (BP) and autonomic nervous system in humans. Considerably wide individual variations have been observed in the response, but the background factors behind the wide individual variations remain unknown. Previous studies have reported that resting circulatory variables and baroreflex sensitivity, and also the response of BP and muscle sympathetic nerve activity with mental stress and upright tilting are different between subjects with and without family history of hypertension (FH). We tested the hypothesis that the response of BP with fragrance inhalation of grapefruit essential oil (GF) was different between subjects with (FH+) and without FH (FH−). Methods: Eighteen healthy subjects participated in this study (FH+, n = 8; FH−, n = 10). While subjects in the supine position, they breathed blank air through a face mask for 10 min as baseline (BL). Then, they inhaled air with the fragrance of GF from Douglas bags for 10 min. Beat‐by‐beat heart rate and BP were recorded continuously. Cardiovagal baroreflex sensitivity was determined with data for the last 2 min of each stage, as the slope of the liner regression between beat‐by‐beat changes in systolic BP and R‐R interval. Results: At 6 to 10 min of BL, heart rate, systolic and diastolic BP was not significantly different between FH+ group and FH− group. During GF inhalation, diastolic BP in FH− group increased significantly (p < 0.05) from BL whereas it remained unchanged in FH+ group. Systolic BP and heart rate remained unchanged during GF inhalation in both groups. There were no significant changes in baroreflex sensitivity with fragrance inhalation in both groups. Conclusions: The FH is a possible background factor behind the individual variation observed in the response of BP with fragrance inhalation of GF. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

Purpose To investigate whether mental fatigue induced by psychological tasks during whole-body surface cooling influences subsequent endurance exercise performance and whether subjective fatigue is associated with performance variability and neuroendocrine responses. Methods Nine young adults participated in two trials: a mental stress (MS) trial involving the Stroop test (500 stimuli/set × 2) and a control (CON) trial involving watching a video. Both were conducted during whole-body surface cooling using a water-perfused suit (10 °C, 10 min, then 15 °C, 85 min). The time to exhaustion (TE) during cycling at 80% peak oxygen uptake was evaluated. Chalder’s fatigue score (CFS), plasma adrenaline ([Ad]_p), noradrenaline ([Norad]_p), and cortisol ([Corti]_p) concentrations were measured before and after intervention and exercise. Results After the intervention, the CFS increased in the MS trial, but not in the CON trial. [Ad]_p and [Norad]_p remained unchanged after the intervention and increased after exercise in both trials, and an increase with exercise was prominent in the MS trial. [Corti]_p remained unchanged. TE decreased by 5.7% in the MS trial. However, this was not statistically significant. The difference (Δ) in TE between trials was significantly negatively correlated with ΔCFS (r = − 0.919, P = 0.002). ΔCFS was significantly positively correlated with Δ[Norad]_p (r = 0.795, P = 0.010), while not with [Ad]_p or [Corti]_p. Conclusion Mental fatigue accompanied by whole-body surface cooling variably influences subsequent endurance exercise performance with decrements associated with greater subjective fatigue and heightened sympathoadrenal–medullary activity though trial-level effects were not significant. There was no apparent hypothalamic–pituitary–adrenal axis involvement.