Pupil Dynamics Predict Exercise Brain Stimulation: An Overview of Exercise Pupillometry.

Proper physical activity, even at a very-light-intensity such as walking or slow running, improves brain health related to prefrontal executive function and hippocampal memory. However, the neural mechanism behind the cognitive enhancement that occurs during dynamic aerobic exercise is elusive and remains unclear in humans. Recently, pupillometry has been attracting attention as a kind of readout of the brain's ascending arousal mechanism, especially for brain noradrenergic and cholinergic system activation. Thus, to identify the neural mechanism behind the effects of very-light-intensity exercise, our recent work has focused on pupillometry during aerobic exercise, and we have successfully shown the efficacy of pupil dilation as a biological marker, even during very-light-/light-intensity exercise (below the ventilatory threshold). Interestingly, neuromelanin-MRI contrast in the LC, a marker of LC integrity, predicted the magnitude of exercise-induced pupil dilation and psychological arousal changes at the individual level. In addition, pupil dilation during exercise predicted the positive impact of acute very-light-/light-intensity exercise on prefrontal executive performance and hippocampal memory performance. The series of exercise pupillometry studies we will discuss here provides essential insights into the neural substrates of the advantages of exercise-induced brain stimulation in humans.

Previous researchers have reported that aerobic exercise improves cognition in older adults; however, few researchers have examined the role of arousal on improvements in cognition after exercise. The purpose of this study was to understand how changes in arousal acutely affect changes in cognitive performance after a single session of light compared to moderate intensity aerobic exercise. Cognitively normal older adults (N = 34) were enrolled in a randomized controlled trial where they were asked to complete the N-back task with faces, a cognitive task used to test working memory, in an fMRI scanner. On separate days, the task was completed before and 15 to 20 minutes after light and moderate intensity exercise. An intervention was also completed, but our question focuses on the acute effects of exercise rather than training. Arousal was measured before and after exercise through a questionnaire and a direct measure of physiological activation of the sympathetic nervous system with galvanic skin response (GSR). On average, resting GSRs decreased from pre- to post-exercise scan; however, the change was not statistically significant. The decrease in arousal after light exercise indicated that older adults had decreased sympathetic activity after both light and moderate intensity exercise. By contrast, N-back task performance improved most after moderate compared to light intensity exercise. Together, evidence that sympathetic activity tended to decrease generally for both intensities, whereas cognitive improvements were more specific, suggests that changes in arousal at rest were not a critical factor connecting exercise and improved working memory in this study.

The purpose of this study is to examine beliefs and behaviors regarding exercise during pregnancy in pregnant and postpartum women living in rural communities. Surveys were distributed in healthcare settings and via social media to pregnant and postpartum (< 3months) women living in rural communities. Seventy-five women (28.1 ± 5.4year) participated. Nearly all believed light (96%) and moderate (89%) intensity exercise are safe to perform during pregnancy, while fewer agreed vigorous intensity (52%) or resistance (40%) exercise is safe. Most (88%) believed women can continue their exercise regimen, and 73% believed that previously inactive women can begin training while pregnant. Only one-third of women met recommendations for cardiorespiratory exercise. The majority (66%) never engaged in vigorous exercise, and most (73%) did not participate in resistance exercise. Pregnant women in rural communities participate in light intensity exercise, but are largely not meeting guidelines for aerobic or resistance training. Knowledge related to safe exercises, particularly resistance training, during pregnancy is limited. Targeted education and programmatic planning are needed in this population regarding exercise guidelines.

Cognitive decline associated with type 2 diabetes mellitus (T2DM) is a risk factor to impair human health. Although light-intensity exercise prevents hippocampal memory dysfunction in pre-symptomatic T2DM animals by altering hippocampal lactate transport and neurotrophic factors, the effects of light-intensity exercise in an advanced stage of T2DM animals remain unclear. Here, ob/ob mice, an animal model of T2DM, were subjected to light-intensity exercise (5.0m/min) for 30min/day, five days/week for four weeks. The effects of light-intensity exercise on hippocampal complications, mRNA expressions of monocarboxylate transporter (MCT), and miRNA levels were assessed. The light-intensity exercise improved hippocampal memory retention in ob/ob mice. Downregulated hippocampal Mct2 mRNA levels in T2DM were improved with light-intensity exercise. Hippocampal mRNA levels of Mct1 and Mct4 were unchanged within groups. Based on miRNA sequencing, sedentary ob/ob mice exhibited that 71 miRNAs were upregulated, and 77 miRNAs were downregulated in the hippocampus. In addition, the exercise significantly increased 24 miRNAs and decreased 4 miRNAs in the T2DM hippocampus. The exercise reversed T2DM-induced alterations of hippocampal 9 miRNAs, including miR-200a-3p. Our findings imply that miR-200a-3p/Mct2 in the hippocampus would be a possible clinical target for treating T2DM-induced memory dysfunction.

Unexpected and task-irrelevant sounds can impair performance in a task. It has been shown that highly arousing emotional distractor sounds impaired performance less compared to moderately arousing neutral distractor sounds. The present study tests whether these differential emotion-related distraction effects are directly related to an enhancement of arousal evoked by processing of emotional distractor sounds.We disentangled costs of orienting of attention and benefits of increased arousal levels during the presentation of highly arousing emotional and moderately arousing neutral novel sounds that were embedded in a sequence of repeated standard sounds. We used sound-related pupil dilation responses as a marker of arousal and RTs as a marker of distraction in a visual categorization task in 57 healthy young adults. Multilevel analyses revealed increased RT and increased pupil dilation in response to novel vs. standard sounds. Emotional novel sounds reduced distraction effects on the behavioral level and increased pupil dilation responses compared to neutral novel sounds. Bayes Factors revealed strong evidence against an inverse proportional relationship between behavioral distraction effects and sound-related pupil dilation responses for emotional sounds. Given that the activity of the locus coeruleus has been linked to both changes in pupil diameter and arousal, it may embody an indirect relationship as a common antecedent by the release of norepinephrine into brain networks involved in attention control and control of the pupil. The present study provides new insights into the relation of changes in arousal and attentional distraction during the processing of emotional task-irrelevant novel sounds.

Physiological responses are generally involuntary; however, real-time feedback enables, at least to a certain extent, to voluntary control automatic processes. Recently, it was demonstrated that even pupil dilation is subject to controlled interference. To address effects of training on the ability to exercise control on pupil dilation, the current study examines repeated exercise over seven successive days. Participants utilize self-induced changes in arousal to increase pupil diameter, real-time feedback was applied to evaluate and improve individual performance. We observe inter-individual differences with regard to responsiveness of the pupillary response: six of eight participants considerably increase pupil diameter already during the first session, two exhibit only slight changes, and all showed rather stable performance throughout training. There was a trend towards stronger peak amplitudes that tend to occur increasingly early across time. Hence, higher cognitive control on pupil dilations can be practiced by most users and may therefore provide an appropriate input mechanism in human-computer interaction.

The purpose of this study was to compare resistance training (RT) (one set vs three sets) combined with aerobic training (AT) versus AT alone in persons with coronary artery disease. Subjects (n = 72) were randomized to AT (5 d x wk(-1)) or combined AT (3 d x wk(-1)) with either one set (AT/RT1) or three sets (AT/RT3) of RT performed 2 d x wk(-1). VO2peak, ventilatory anaerobic threshold (VAT), strength and endurance, body composition, and adherence were measured before and after 29 wk of training. Fifty-three subjects (mean +/- SEM age 61 +/- 2) completed the training. The increase from baseline in VO2peak (L x min(-1)) averaged 11% for AT (P < 0.05), 14% for AT/RT1 (P < 0.01), and 18% for AT/RT3 (P < 0.001), however, the difference between groups was not significant. VAT improved significantly in the AT/RT3 group only (P < 0.05). The AT/RT3 group gained more lean mass than the AT group (1.5 versus 0.4 kg, P < 0.01), yet gains between AT/RT1 and AT were similar (P = 0.2). Only AT + RT groups demonstrated a reduction in body fat (P < 0.05). Strength and endurance increased more in the AT + RT groups than AT alone (P < 0.05). Adherence to number of sets performed was lower in AT/RT3 than AT/RT1 (P < 0.02). Combined AT + RT yields more pronounced physiological adaptations than AT alone and appears to be superior in producing improvements in VO2peak, muscular strength and endurance, and body composition. The data support the use of multiple set RT for patients desiring an increased RT stimulus which may further augment parameters that affect VO2peak, VAT, lower body endurance, and muscle mass in a cardiac population.

Short and long-term effects of water-based aerobic and concurrent training on cardiorespiratory capacity and strength of older women

PurposeMaintaining high adherence rates (session attendance and compliance) in exercise programs during breast cancer treatment can be challenging. We aimed to identify adherence rates and predictors to an exercise program during adjuvant breast cancer treatment.MethodsNinety-two patients with localized breast cancer undergoing chemotherapy were randomly assigned to an 18-week supervised moderate-to-high intensity aerobic and resistance exercise program, including two 1-hour sessions/week. Additionally, participants were asked to be physically active for at least 30 minutes/day on at least three other days. We report median percentages for attendance, compliance with the prescribed duration and intensity of aerobic and muscle strength exercises, and the exercise advice given. Predictors included in univariate and multivariable linear regression models were demographical, tumor- and treatment-related factors, constructs of the theory of planned behavior, psychological and physical factors.ResultsPatients attended 83% (interquartile range: 69–91%) of the supervised sessions. Compliance with the duration of aerobic exercise, high-intensity aerobic exercise (cycling at the ventilatory threshold), muscle strength exercises and the exercise advice were 88%(64–97%), 50%(22–82%), 84%(65–94%) and 61%(33%–79%), respectively. Education, radiotherapy, BMI and physical fatigue were important predictors of adherence to supervised exercise. Beliefs about planned behaviors were important predictors, especially for compliance with the exercise advice.ConclusionsAttendance to and compliance with an 18-week aerobic and strength exercise program were high. The lowest compliance was found for high-intensity supervised aerobic exercise. The identified predictors should be considered when designing or adapting exercise programs for patients with localized breast cancer to increase adherence.Trial registrationCurrent Controlled Trials ISRCTN43801571Dutch Trial Register NTR2138

The purpose of this study was to evaluate the effect of exercise training intensity relative to the ventilatory threshold (VT) on changes in work (watts) and VO2 at the ventilatory threshold and at maximal exercise in previously sedentary participants in the HERITAGE Family Study. We hypothesized that those who exercised below their VT would improve less in VO2 at the ventilatory threshold (VO2vt) and VO2max than those who trained at an intensity greater than their VT. Supervised cycle ergometer training was performed at the 4 participating clinical centers, 3 times a week for 20 weeks. Exercise training progressed from the HR corresponding to 55% VO2max for 30 minutes to the HR associated with 75% VO2max for 50 minutes for the final 6 weeks. VT was determined at baseline and after exercise training using standardized methods. 432 sedentary white and black men (n = 224) and women (n = 208), aged 17 to 65 years, were retrospectively divided into groups based on whether exercise training was initiated below, at, or above VT. 1) Training intensity (relative to VT) accounting for about 26% of the improvement in VO2vt (R2 = 0.26, p < 0.0001). 2) The absolute intensity of training in watts (W) accounted for approximately 56% of the training effect at VT (R2 = 0.56, p < 0.0001) with post-training watts at VT (VT(watts)) being not significantly different than W during training (p > 0.70). 3) Training intensity (relative to VT) had no effect on DeltaVO2max. These data clearly show that as a result of aerobic training both the VO2 and W associated with VT respond and become similar to the absolute intensity of sustained (3 x /week for 50 min) aerobic exercise training. Higher intensities of exercise, relative to VT, result in larger gains in VO2vt but not in VO2max.

Deep brain stimulation of the subthalamic nucleus is an accepted treatment for the motor complications of Parkinson's disease. The therapeutic mechanism of action remains incompletely understood. Although the results of deep brain stimulation are similar to the results that can be obtained by lesional surgery, accumulating evidence from functional imaging and clinical neurophysiology suggests that the effects of subthalamic nucleus-deep brain stimulation are not simply the result of inhibition of subthalamic nucleus activity. Positron emission tomography/single-photon emission computed tomography has consistently demonstrated changes in cortical activation in response to subthalamic nucleus-deep brain stimulation. However, the technique has limited spatial and temporal resolution, and therefore the changes in activity of subcortical projection sites of the subthalamic nucleus (such as the globus pallidus, substantia nigra, and thalamus) are not as clear. Clarifying whether clinically relevant effects from subthalamic nucleus-deep brain stimulation in humans are mediated through inhibition or excitation of orthodromic or antidromic pathways (or both) would contribute to our understanding of the precise mechanism of action of deep brain stimulation and may allow improvements in safety and efficacy of the technique. In this review we discuss the published evidence from functional imaging studies of patients with subthalamic nucleus-deep brain stimulation to date, together with how these data inform the mechanism of action of deep brain stimulation.

The double product is the product of the heart rate and systolic blood pressure. The double product break point (DPBP) is a physiologic threshold that occurs at similar exercise intensities to that of the ventilatory threshold (VT). The influence of aerobic exercise training on the DPBP has not yet been examined. The purpose of this study was to examine whether aerobic exercise training (ET) increases the exercise intensity at which the DPBP occurs, and whether it increases in a similar fashion to the VT. Seven males and 11 females, all sedentary (mean ± SD: age = 29.9 ± 10.5 years) underwent supervised cardiopulmonary exercise testing using a cycle ergometer ramp protocol at baseline and after 8 weeks of vigorous ET on a cycle ergometer. The VT was determined by gas analysis and the V-slope method. Experienced observers using standardized instructions visually determined the DPBP. Following ET, VO(2 peak), maximal workload, and body composition variables all showed significant positive changes. The VO(2) at which the DPBP and VT occurred increased significantly from baseline to follow-up (P < 0.001). At baseline and at follow-up, the DPBP and VT did not differ. The DPBP and VT were significantly correlated to each other at both time points. Results suggest that the DPBP responds to ET in a similar fashion to that of the VT, and may be an easier and more useful marker of the VT for exercise training purposes.

The anaerobic threshold (AT) is a good indicator of aerobic fitness, commonly determined by ventilatory variables - ventilatory threshold (VT) - and more recently, by indexes of heart rate variability (HRVT). However, there are few studies in young people with overweight and obesity. PURPOSE: To compare the HRVT, determined by two HRV index, with the VT in young people with different body mass index. METHODS: 31 sedentary men (21.2 ± 1.7 years), 10 eutrophic (E: 22.7 ± 1.7 kg.m-2), 10 overweight (Ov: 27.0 ± 1.5 kg.m-2) and 11 obese (O: 33.7 ± 2.7 kg.m-2) were evaluated. A maximum incremental test on a cycle ergometer (INBRASPORT®, CG-04 model), with increments of 15 watts/min until volitional exhaustion was performed. The RR intervals were measured (Polar®, RS800CX model) and treated (Kubios HRV) to obtain SD1 and RMSSD index. The HRVT was determined in the first exercise intensity with SD1 (HRVTSD1) and RMSSD (HRVTRMSSD) less than 3 ms (Lima, 1999). The VT was determined by analysis of the ventilatory equivalent (VO2000, MEDICAL Graphics®) O2 (VE/VO2) and CO2 (VE/VCO2). RESULTS: The HRVTSD1 was determined in 100% and HRVTRMSSD in 90.3% of subjects. There were difference between methods (Kruss Kall Wallis Test and Duns Post Hoc, p<0.05; different letters indicate significant difference between methods) to the load (W) (E - HRVTSD1: 105 ± 36 HRVTRMSSD: 132 ± 57, VT: 109 ± 36; Ov - HRVTSD1: 85 ± 36; HRVTRMSSD: 101 ± 22, VT: 90 ± 16; O - HRVTSD1: 105 ± 30a; HRVTRMSSD: 130 ± 16b, VT: 96 ± 24a) in obese, as well to the HR (bpm) (E - HRVTSD1: 138 ± 6a; HRVTRMSSD: 157 ± 17ab, VT: 140 ± 17b - Ov - HRVTSD1: 134 ± 14; HRVTRMSSD: 142 ± 13, VT: 133 ± 15; O - HRVTSD1: 137 ± 15; HRVTRMSSD: 150 ± 12, VT: 139 ± 33) in eutrophic. There were difference between groups (different symbols indicate significant difference between groups) in VO2. (ml.kg-1.min-1): HRVTSD1 (E: 22.2 ± 6.1*, Ov: 17.18 ± 5.5#; O: 16.8 ± 2.7#); HRVTRMSSD (E: 20.9 ± 4 2; Ov: 19.7 ± 6.1, O: 18.7 ± 2.4); VT (E: 20.9 ± 6.0*, Ov: 18.0 ± 4.0*#, O: 15.3 ± 2.4#). CONCLUSION: Sedentary young people with different BMI have similar aerobic fitness determined by VT and HRVTSD1. However, RMSSD index seem overestimate the VT in eutrophic (HR values) and obese (watts values), which refers caution in the use of this HRV index to assess aerobic fitness and exercise prescription in this population. Supported by FAPEMAT (151411/2014), CNPq

ObjectiveTo examine the effect of acute aerobic exercise at moderate-to-vigorous and light intensity on food reward, appetite sensation, and energy intake (EI) in physically inactive adults.MethodsTwenty inactive, healthy adults (mean age: 21 ± 3 years) completed two trials (i.e. moderate-to-vigorous and light-intensity exercise) in a randomised, crossover design. Participants performed a 40-min cycling bout at either 50% or 20% peak power output in a counterbalanced order. Before and after exercise bouts, liking and wanting for fat and sweet/savoury categories of food were assessed by the Leeds Food Preference Questionnaire, along with subjective ratings of appetite and state food cravings. EI was evaluated by ad libitum meals following exercise bouts.ResultsResults showed increased implicit wanting for high-fat relative to low-fat foods (p = .04, drm = 0.50) and savoury relative to sweet foods following exercise bouts (p = .04, drm = −0.49) without intensity-specific effects. Exercise bouts also led to increased subjective appetite (p < 0.001, η2p = 0.60) and state food cravings (p = 0.001, η2p = 0.44) without intensity-specific differences. There was no difference between exercise intensities on absolute EI, whereas relative EI was lower after moderate-to-vigorous exercise relative to light exercise (p < 0.001, drm = −1.56).ConclusionAcute aerobic exercise, regardless of intensity, may lead to increased wanting for high-fat relative to low-fat and savoury relative to sweet-tasting foods, as well as enhanced appetite sensation and food cravings in physically inactive adults. Moderate-to-vigorous exercise does not induce additional energy intake relative to light exercise.

1. To investigate the effect of an exercise training programme on antihypertensive drug requirements, 19 sedentary subjects (14 men and five women) with mild essential hypertension (systolic blood pressure greater than 140 mmHg but less than 180 mmHg), aged 29-55 years, were randomly assigned to 16 weeks of moderate intensity exercise or light intensity exercise (control), and titrated on antihypertensive drug therapy (captopril and hydrochlorothiazide) until resting systolic blood pressure (sitting) of less than 140 mmHg was achieved. 2. The moderate exercise group (n = 11) followed a graded walk-jog programme to greater than 60% age-predicted maximum heart rate (HRmax), attending 45 min sessions, three times each week. The light exercise group (n = 8) followed a programme of flexibility (stretching exercises) and walking to less than 60% age-predicted HRmax, attending 45 min sessions, three times each week. 3. There was no difference between treatment groups for the level of reduction in both resting systolic and diastolic blood pressure over the 16 weeks (15.64 +/- 10.6/12.81 +/- 9.97 mmHg in the moderate intensity group and 15.31 +/- 10.9/7.7 +/- 7.1 mmHg in the light intensity group). The change in 24 h ambulatory blood pressure profile was also similar in both treatment groups. The final antihypertensive drug requirements to achieve these changes in blood pressure was not significantly different between the two treatment groups. This was despite a significant improvement in submaximal exercise performance in the moderate intensity exercise group (P less than 0.001). 4.(ABSTRACT TRUNCATED AT 250 WORDS)