Effects of acute bouts of endurance exercise on retinal vessel diameters are age and intensity dependent.
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ABSTRACT:
SUBMITTER: Nussbaumer M
PROVIDER: S-EPMC4082577 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Acute exercise bouts alter resting state functional connectivity (rs-FC) within cognitive, sensorimotor, and affective networks, but it remains unknown how these effects are influenced by exercise intensity. Twenty-five male athletes underwent individual fitness assessments using an incremental treadmill test. On separate days, they performed 'low' (35% below lactate threshold) and 'high' (20% above lactate threshold) intensity exercise bouts of 30?min. Rs-fMRI and Positive and Negative Affect Scale (PANAS) were acquired before and after each exercise bout. Networks of interest were extracted from twenty-two participants (3 dropouts). Pre-to-post changes and between conditions effects were evaluated using FSL's randomise by applying repeated measures ANOVA. Results were reported at p?<?0.05, corrected for multiple comparisons using threshold free cluster enhancement. PANAS revealed a significant increase in positive mood after both exercise conditions. Significant effects were observed between conditions in the right affective and reward network (ARN), the right fronto parietal network (FPN) and the sensorimotor network (SMN). Pre-to-post comparisons after 'low' exercise intensity revealed a significant increase in rs-FC in the left and right FPN, while after 'high'-intensity exercise rs-FC decreased in the SMN and the dorsal attention network (DAN) and increased in the left ARN. Supporting recent findings, this study is the first to report distinct rs-FC alterations driven by exercise intensity: (i) Increased rs-FC in FPN may indicate beneficial functional plasticity for cognitive/attentional processing, (ii) increased rs-FC in ARN may be linked to endogenous opioid-mediated internal affective states. Finally, (iii) decreased rs-FC in the SMN may signify persistent motor fatigue. The distinct effects on rs-FC fit with theories of transient persistent network alterations after acute exercise bouts that are mediated by different exercise intensities and impact differentially on cognitive/attentional or affective responses.
| S-EPMC6971822 | biostudies-literature
Project description:This study determined whether performing a single moderate- or vigorous-intensity exercise bout impacts daily physical activity energy expenditure (PAEE, by accelerometer). Overweight/obese postmenopausal women underwent a 5-month caloric restriction and moderate- (n = 18) or vigorous-intensity (n = 18) center-based aerobic exercise intervention. During the last month of intervention, in women performing moderate-intensity exercise, PAEE on days with exercise (577.7 ± 219.7 kcal·d(-1)) was higher (P = .011) than on days without exercise (450.7 ± 140.5 kcal·d(-1)); however, the difference (127.0 ± 188.1 kcal·d(-1)) was much lower than the energy expended during exercise. In women performing vigorous-intensity exercise, PAEE on days with exercise (450.6 ± 153.6 kcal·d(-1)) was lower (P = .047) than on days without exercise (519.2 ± 127.4 kcal·d(-1)). Thus, women expended more energy on physical activities outside of prescribed exercise on days they did NOT perform center-based exercise, especially if the prescribed exercise was of a higher intensity.
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Project description:We investigated acute exercise-induced gene expression in skeletal muscle adapted to aerobic training. Vastus lateralis muscle samples were taken in ten endurance-trained males prior to, and just after, 4 h, and 8 h after acute cycling sessions with different intensities, 70% and 50% V ˙ O 2 max . High-throughput RNA sequencing was applied in samples from two subjects to evaluate differentially expressed genes after intensive exercise (70% V ˙ O 2 max ), and then the changes in expression for selected genes were validated by quantitative PCR (qPCR). To define exercise-induced genes, we compared gene expression after acute exercise with different intensities, 70% and 50% V ˙ O 2 max , by qPCR. The transcriptome is dynamically changed during the first hours of recovery after intensive exercise (70% V ˙ O 2 max ). A computational approach revealed that the changes might be related to up- and down-regulation of the activity of transcription activators and repressors, respectively. The exercise increased expression of many genes encoding protein kinases, while genes encoding transcriptional regulators were both up- and down-regulated. Evaluation of the gene expression after exercise with different intensities revealed that some genes changed expression in an intensity-dependent manner, but others did not: the majority of genes encoding protein kinases, oxidative phosphorylation and activator protein (AP)-1-related genes significantly correlated with markers of exercise stress (power, blood lactate during exercise and post-exercise blood cortisol), while transcriptional repressors and circadian-related genes did not. Some of the changes in gene expression after exercise seemingly may be modulated by circadian rhythm.
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Project description:Numerous studies suggest beneficial effects of aerobic exercise at moderate intensity on cognition, while the effects of high-intensity exercise are less clear. This study investigated the acute effects of exercise at moderate and high intensities on executive functions in healthy adults, including functional MRI to examine the underlying neural mechanisms. Furthermore, the association between exercise effects and cardiorespiratory fitness was examined. 64 participants performed in two executive function tasks (flanker and Go/No-go tasks), while functional MR images were collected, following two conditions: in the exercise condition, they cycled on an ergometer at either moderate or high intensity (each n = 32); in the control condition, they watched a movie. Differences in behavioral performance and brain activation between the two conditions were compared between groups. Further, correlations between cardiorespiratory fitness and exercise effects on neural and behavioral correlates of executive performance were calculated. Moderate exercise compared to high-intensity exercise was associated with a tendency towards improved behavioral performance (sensitivity index d') in the Go/No-go task and increased brain activation during hit trials in areas related to executive function, attention, and motor processes (insula, superior frontal gyrus, precentral gyrus, and supplementary motor area). Exercise at high intensity was associated with decreased brain activation in those areas and no changes in behavioral performance. Exercise had no effect on brain activation in the flanker task, but an explorative analysis revealed that reaction times improved after high-intensity exercise. Higher cardiorespiratory fitness was correlated with increased brain activation after moderate exercise and decreased brain activation after high-intensity exercise. These data show that exercise at moderate vs. high intensity has different effects on executive task performance and related brain activation changes as measured by fMRI and that cardiorespiratory fitness might be a moderating factor of acute exercise effects. Thus, our results may contribute to further clarify the neurophysiological mechanisms underlying the beneficial effects of exercise on cognition.
| S-EPMC6589258 | biostudies-literature
Project description:ObjectivesTo examine the affective responses during a single bout of a low-volume HIIE in active and insufficiently active men.Materials and methodsFifty-eight men (aged 25.3 ± 3.6 years) volunteered to participate in this study: i) active (n = 29) and ii) insufficiently active (n = 29). Each subject undertook i) initial screening and physical evaluation, ii) maximal exercise test, and iii) a single bout of a low-volume HIIE. The HIIE protocol consisted of 10 x 60s work bouts at 90% of maximal treadmill velocity (MTV) interspersed with 60s of active recovery at 30% of MTV. Affective responses (Feeling Scale, -5/+5), rating of perceived exertion (Borg's RPE, 6-20), and heart rate (HR) were recorded during the last 10s of each work bout. A two-factor mixed-model repeated measures ANOVA, independent-samples t test, and chi-squared test were used to data analysis.ResultsThere were similar positive affective responses to the first three work bouts between insufficiently active and active men (p > 0.05). However, insufficiently active group displayed lower affective responses over time (work bout 4 to 10) than the active group (p < 0.01). Also, the insufficiently active group displayed lower values of mean, lowest, and highest affective response, as well as lower values of affective response at the highest RPE than the active group (p < 0.001). There were no differences in the RPE and HR between the groups (p > 0.05).ConclusionsInsufficiently active and active men report feelings of pleasure to few work bouts (i.e., 3-4) during low-volume HIIE, while the affective responses become more unpleasant over time for insufficiently active subjects. Investigations on the effects of low-volume HIIE protocols including a fewer number of work bouts on health status and fitness of less active subjects would be interesting, especially in the first training weeks.
| S-EPMC4814045 | biostudies-literature
Project description:BackgroundCentral retinal arteriolar (CRAE) and venular (CRVE) diameter equivalents are predictive for cardiovascular and all-cause mortality in humans. The aim of this study was to investigate the inter- and intraobserver variability for the assessment of CRAE and CRVE in mice using fluorescein contrast enhancement as compared to crude analysis.MethodsThree high quality images with (F) and without fluorescein (NF) of eight mice (type C57BL) were recorded and analysed by two independent experienced investigators to investigate interobserver variability. In addition, one investigator analysed 20 F and 20 NF images twice to investigate intraobserver variability. The time course of CRAE and CRVE vessel responses after fluorescein injection were recorded in one mouse every 30 seconds for 15 minutes.ResultsThe interobserver variability was lower in F images compared to NF images for CRAE (r = 0.99, p < 0.001 vs. r = 0.65, p = 0.083) and CRVE (r = 0.99, p < 0.001 vs. r = 0.79, p = 0.019). Intraobserver variability for CRAE (r = 0.99, p < 0.001 vs. r = 0.48, p = 0.032) and CRVE (r = 0.98, p < 0.001 vs. r = 0.86, p < 0.001) were lower in F compared to NF images. Fluorescein injection induced vascular staining mimicking vessel dilation (+14%) followed by a long-lasting stable staining phase well suited for precise measurements.ConclusionsMeasurement variability can be optimized by use of fluorescein as contrast enhancement in mice. Standardization for time of image acquisition after fluorescein injection is advisable. Translation of static retinal vessel analysis into a rodent model has the potential to bridge the research gap between proof of concept studies in animals and clinical studies in humans.
| S-EPMC9302806 | biostudies-literature
Project description:AimsMild cognitive dysfunction has been identified in children and adults with type 1 diabetes, but most studies have failed to find a relationship between severe hypoglycemia and cognition, despite reports of such associations in older adults with type 2 diabetes. Focusing on older adults with type 1 diabetes, we examined the associations between cognitive performance and recent episodes of severe hypoglycemia, retinal vessel diameters and the presence of micro- and macrovascular complications.MethodsCognitive functioning was assessed in 244 participants enrolled in the Wisconsin Epidemiologic Study of Diabetic Retinopathy. The mean (SD; range) age at assessment in 2012-14 was 55.2 (8.3; 37-82) years and the mean (SD) duration of diabetes was 41.1 (5.6) years. Three cognitive domains were assessed in this cross-sectional study: mental efficiency and executive function, nonverbal memory, and verbal memory.ResultsMultivariate modeling demonstrated that although age and/or education are most strongly associated with performance on measures of mental efficiency, three diabetes-related variables were also associated with poorer test scores: an episode of severe hypoglycemia in the past year (β=-0.360 [95% CI, -0.672, -0.047]), retinal arteriolar and venular diameters (β=0.140 [95% CI, 0.062, 0.219]; β=-0.127 [95% CI -0.207, -0.047]), and carotid artery plaque (β=-0.372 [95% CI -0.741, -0.003]). In addition, recent severe hypoglycemia was associated with poorer nonverbal memory (β=-0.522 [95% CI, -0.849, -0.194]).ConclusionsFor middle-aged and older adults with long-duration type 1 diabetes, poorer cognition was associated with a recent episode of severe hypoglycemia as well as with the presence of micro- and/or macrovascular conditions. Given the increasing numbers of aging adults with type 1 diabetes, future longitudinal studies are needed to identify causality and to determine whether diabetes management techniques that reduce the onset or severity of vascular complications and hypoglycemia can also reduce the risk of cognitive dysfunction in this population.
| S-EPMC5050129 | biostudies-literature
Project description:Introduction: Technological advances have made high-altitude ski slopes easily accessible to skiers of all ages. However, research on the effects of hypoxia experienced during excursions to such altitudes on physiological systems, including the ocular system, in children is scarce. Retinal vessels are embryologically of the same origin as vessels in the brain, and have similar anatomical and physiological characteristics. Thus, any hypoxia-related changes in the morphology of the former may reflect the status of the latter. Objective: To compare the effect of one-day hypoxic exposure, equivalent to the elevation of high-altitude ski resorts in North America and Europe (∼3,000 m), on retinal vessel diameter between adults and children. Methods: 11 adults (age: 40.1 ± 4.1 years) and 8 children (age: 9.3 ± 1.3 years) took part in the study. They spent 3 days at the Olympic Sports Centre Planica (Slovenia; altitude: 940 m). During days 1 and 2 they were exposed to normoxia (FiO2 = 0.209), and day 3 to normobaric hypoxia (FiO2 = 0.162 ± 0.03). Digital high-resolution retinal fundus photographs were obtained in normoxia (Day 2) and hypoxia (Day 3). Central retinal arteriolar equivalent (CRAE) and venular equivalents (CRVE) were determined using an Automated Retinal Image Analyser. Results: Central retinal arteriolar and venular equivalents increased with hypoxia in children (central retinal arteriolar equivalent: 105.32 ± 7.72 µm, hypoxia: 110.13 ± 7.16 µm, central retinal venular equivalent: normoxia: 123.39 ± 8.34 µm, hypoxia: 130.11 ± 8.54 µm) and adults (central retinal arteriolar equivalent: normoxia: 105.35 ± 10.67 µm, hypoxia: 110.77 ± 8.36 µm; central retinal venular equivalent: normoxia: 126.89 ± 7.24 µm, hypoxia: 132.03 ± 9.72 µm), with no main effect of group or group*condition interaction. A main effect of condition on central retinal arteriolar and venular equivalents was observed (central retinal arteriolar equivalent:normoxia: 105.34 ± 9.30 µm, hypoxia: 110.50 ± 7.67 µm, p < 0.001; central retinal venular equivalent: normoxia: 125.41 ± 7.70 µm, hypoxia: 131.22 ± 9.05 µm, p < 0.001). Conclusion: A 20-hour hypoxic exposure significantly increased central retinal arteriolar and venular equivalents in adults and children. These hypoxia-induced increases were not significantly different between the age groups, confirming that vasomotor sensitivity of the retinal vessels to acute hypoxia is comparable between adults and prepubertal children.
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Project description:Noninvasive ventilation (NIV) during exercise has been suggested to sustain higher training intensity but the type of NIV interface, patient-ventilator asynchronies (PVA) or technological limitation of the ventilator may interfere with exercise. We assessed whether these parameters affect endurance exercise capacity in severe COPD patients. In total, 21 patients with severe COPD not eligible to home NIV performed three constant workload tests. The first test was carried out on spontaneous breathing (SB) and the following ones with NIV and a nasal or oronasal mask in a randomized order. PVA and indicators of ventilator performance were assessed through a comprehensive analysis of the flow pressure tracing raw data from the ventilator. The time limit was significantly reduced with both masks (406 s (197-666), 240 s (131-385) and 189 s (115-545), p < 0.01 for tests in SB, with oronasal and nasal mask, respectively). There were few PVA with an oronasal mask (median: 3.4% (1.7-5.2)) but the ventilator reached its maximal generating capacity (median flowmax: 208.0 L/s (189.5-224.8) while inspiratory pressure dropped throughout exercise (from 10.1 (9.4-11.4) to 8.8 cmH2O (8.6-10.8), p < 0.01). PVA were more frequent with nasal mask (median: 12.8% (3.2-31.6), p < 0.01). Particularly, the proportion of patients with ineffective efforts > 10% was significantly higher with nasal interface (0% versus 33.3%, p < 0.01). NIV did not effectively improve endurance capacity in COPD patients not acclimated to home NIV. This was due to a technological limitation of the ventilator for the oronasal mask and the consequence either of an insufficient pressure support or a technological limitation for the nasal mask.
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Project description:This study examined whether intensity of endurance stimulus within a concurrent training paradigm influenced the phosphorylation of signaling proteins associated with the mTOR and AMPK networks. Eight male cyclists completed (1) resistance exercise (RES), 6 × 8 squats at 80% 1-RM; (2) resistance exercise and moderate intensity cycling of 40 min at 65% V̇O2peak, (RES + MIC); (3) resistance exercise and high intensity interval cycling of 40 min with 6 alternating 3 min intervals of 85 and 45% V̇O2peak (RES + HIIC), in a cross-over design. Muscle biopsies were collected at rest and 3 h post-RES. There was a main effect of condition for mTORS2448 (p = 0.043), with a greater response in the RES + MIC relative to RES condition (p = 0.033). There was a main effect of condition for AMPKα2T172 (p = 0.041), with a greater response in RES + MIC, relative to both RES + HIIC (p = 0.026) and RES (p = 0.046). There were no other condition effects for the remaining protein kinases assessed (p > 0.05). These data do not support a molecular interference effect in cyclists under controlled conditions. There was no intensity-dependent regulation of AMPK, nor differential activation of anabolism with the manipulation of endurance exercise intensity.
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