Moderate-intensity Treadmill Walking Research Articles

Neoadjuvant Exercise Therapy in Prostate Cancer

Observational data have shown that postdiagnosis exercise is associated with reduced risk of prostate cancer death. The feasibility and tumor biological activity of exercise therapy is not known. To identify recommended phase 2 dose of exercise therapy for patients with prostate cancer. This single-center, phase 1a dose-finding trial was conducted at a tertiary cancer center using a patientcentric, decentralized platform and included 53 inactive men with treatment-naive localized prostate cancer scheduled to undergo surgical resection between June 2019 and January 2023. Data were analyzed in June 2024. Six escalated exercise therapy dose levels ranging from 90 to 450 minutes per week of individualized, moderate-intensity treadmill walking, allocated using adaptive continual reassessment. All exercise therapy sessions were conducted remotely with real-time monitoring. Feasibility was evaluated by relative exercise dose intensity (REDI). A dose level was considered feasible if 70% or more of patients achieved an REDI of 75% or greater. Activity end points were changes in tumor cell proliferation (Ki67) and plasma prostate-specific antigen levels between pretreatment and postintervention. Safety and changes in patient physiology were also assessed. A total of 53 men were enrolled (median [IQR] age, 61 [56-66] years). All dose levels were feasible (≥75% REDI). The mean (95% CI) changes in Ki67 were 5.0% (-4.3% to 14.0%) for 90 minutes per week, 2.4% (-1.3% to 6.2%) for 150 minutes per week, -1.3% (-5.8% to 3.3%) for 225 minutes per week, -0.2% (-4.0% to 3.7%) for 300 minutes per week, -2.6% (-9.2% to 4.1%) for 375 minutes per week, and 2.2% (-0.8% to 5.1%) for 450 minutes per week. Changes in prostate-specific antigen levels were 1.0 ng/mL (-1.8 to 3.8) for 90 minutes per week, 0.2 ng/mL (-1.1 to 1.5) for 150 minutes per week, -0.5 ng/mL (-1.2 to 0.3) for 225 minutes per week, -0.2 (-1.7 to 1.3) for 300 minutes per week, -0.7 ng/mL (-1.7 to 0.4) for 375 minutes per week, and -0.9 ng/mL (-2.4 to 0.7) for 450 minutes per week. No serious adverse events were observed. Overall, 225 minutes per week (approximately 45 minutes per treatment at 5 times weekly) was selected as the recommended phase 2 dose. The results of this nonrandomized clinical trial suggest that neoadjuvant exercise therapy is feasible and safe with promising activity in localized prostate cancer. ClinicalTrials.gov Identifier: NCT03813615.

Effects of three-week intake of Matcha green tea powder on heart rate variability metrics

Introduction: Compared to other green teas, higher intake of multiple phytochemicals is achieved with Matcha green tea consumption. Green tea consumption is known to have metabolic effects but is also consumed for supposed calming effects. The aim of the present study was to examine the effects of encapsulated Matcha green tea on heart rate variability metrics during supine rest, as well as on physiological and metabolic responses during both supine rest and moderate-intensity exercise. Methods: Healthy females (n=8, age: 22±3 yrs, body mass: 68±11 kg, height: 162±5 cm) volunteered. The study employed a placebo-controlled, randomised cross-over design. Time-domain heart rate variability metrics during supine rest (n=5) and physiological and metabolic responses using indirect calorimetry techniques during supine rest and 60-min of moderate-intensity (~ 4-METs) treadmill walking (speed: 4.4±0.5 km·h-1) were measured following 3 weeks of 3 g·day-1 of Matcha green tea or placebo. Results: During supine rest with Matcha green tea, all participants had lower heart rates by 13±7% (P=0.01, d= -1.45), higher mean beat-to-beat RR intervals by 16±9% (P=0.03, d=1.25), higher SDNN by 44±32% (P=0.01, d=0.76) and higher pNN50 by 139±139% (P<0.01, d=1.28). Matcha green tea had no effects on the physiological and metabolic responses during supine rest and moderate-intensity treadmill walking (e.g. respiratory exchange ratio, placebo: 0.78±0.04; Matcha: 0.78±0.03, P=0.87). Fat oxidation during supine rest was correlated (r=0.75, P<0.01) with the moderate-intensity walking induced fat oxidation. Conclusions: In young adult healthy females, Matcha green tea beneficially effects heart rate variability metrics during supine rest indicating an alteration in parasympathetic nervous activity and therefore suggestive of a relaxing effect. Matcha green tea did not change the metabolic responses during supine rest and exercise possibly due to the low respiratory exchange ratio in the female cohort. Future work should address the effectiveness of Matcha green tea during conditions of psychological stress.Keywords: Matcha green tea, heart rate variability, rest, walking, substrate oxidation

Erectile dysfunction and metabolic syndrome components in obese men with psoriasis: response to a 12-week randomized controlled lifestyle modification program (exercise with diet restriction)

BackgroundErectile dysfunction (ED) and metabolic syndrome (MeTS) are highly prevalent in chronic plaque psoriasis (CPP).ObjectiveThe aim of this lifestyle modification study is to explore the response of MeTS components and ED to a 12-week lifestyle modification program (low-calorie diet and moderate-intensity treadmill walking) in 60 obese men with CPP, mild and moderate ED, and MeTS.The design, settings, participants, and interventionIn this lifestyle modification randomized study, a university-based hospital recruitment of 60 obese men with CPP, mild and moderate ED, and MeTS was randomly performed. Men were randomly assigned to the lifestyle modification group (n = 30, received low-calorie diet and moderate-intensity treadmill walking programs) or waitlist group (n = 30). The following outcomes were assessed as follows: body mass index, psoriasis severity (assessed via psoriasis area and severity index), ED (assessed by the five-item internal index of erectile function), and components of MeTS (waist circumference, blood pressure, serum high-density lipoprotein, serum triglycerides, and serum fasting blood glucose).ResultsTrends of significant improvements in all outcomes were documented in favor of the lifestyle modification group. All outcomes of the waitlist group did not show the same reported significant improvements of the lifestyle modification group.ConclusionA 12-week lifestyle modification program as a tool for weight loss in obese men with CPP is a good therapeutic method to improve psoriasis severity and psoriasis-associated ED and MeTS.

Elevations in serum brain-derived neurotrophic factor following occupational heat stress are not influenced by age or common chronic disease

ABSTRACT With global warming, workers are increasingly exposed to strenuous occupations in hot environments. Given age- and disease-associated declines in thermoregulatory function, older workers are at an elevated risk of developing heat-related injuries. Brain-derived neurotrophic factor (BDNF) is thought to confer neuroprotection during acute exercise, however, the influence of environmental heat on BDNF responses during prolonged work remains unclear. Therefore, we evaluated serum BDNF concentrations before and after 180 min of moderate-intensity treadmill walking (200 W/m2) and after 60 min of post-exercise recovery in temperate (wet-bulb globe temperature (WBGT) 16°C) and hot (WBGT 32°C) environments in 13 healthy young men (mean [SD; 22 [3] years), 12 healthy older men (59 [4] years), 10 men with hypertension (HTN) (60 [4] years), and 9 men with type 2 diabetes (T2D) (60 [5] years). In the temperate condition, all but one participant (1 HTN) completed the 180 min of exercise. While exercise tolerance in the heat was lower in older men with HTN (117 min [45]) and T2D (123 min [42]) compared to healthy older men (159 min [31]) (both p ≤ 0.049), similar end-exercise rectal temperatures (38.9°C [0.4]) were observed across groups, paralleled by similar elevations in serum BDNF across groups at end-exercise (+1106 pg/mL [203]) and end-recovery (+938 pg/mL [146]; all p ≤ 0.01) in the heat. No changes in serum BDNF were observed in the temperate condition. Our findings indicate similar BDNF responses in individuals with HTN or T2D compared to their healthy counterparts, despite exhibiting reduced tolerance to heat.

Serum Klotho Concentrations in Young and Older Men During Prolonged Exercise in Temperate and Hot Conditions.

The protein klotho protects cellular function during various physiological stressors, such as exercise, however it is unknown how the age-related decline in klotho production affects responses during exercise, especially in the heat. Our objective was to determine the effect of exercise in temperate and hot environmental conditions on serum klotho concentrations in young and older men. 12 young (mean ± SD: 22 ± 3 years) and 12 older (59 ± 4 years) men performed 180 minutes of moderate-intensity treadmill walking (metabolic rate: 200 W/m2) in a temperate (wetbulb globe temperature [WBGT] 16°C, achieved with 21.9°C, 35% relative humidity [RH]) and hot (WBGT 32°C, achieved with 41.4°C, 35% RH) environment. Serum klotho was assessed before and after exercise, as well as 60-min post-exercise recovery in the respective environments. Absolute klotho concentrations were greater in young versus older men during all measured time points in the temperate (p = 0.032), but not the hot condition (p = 0.064). In the hot condition, the change in serum klotho from baseline was significantly higher after exercise in the heat (mean ± SEM: +251 ± 73 pg/mL) than the temperate (+75 ± 57 pg/mL) environment in both groups (p = 0.026). However, this elevation was not maintained during recovery. We showed that prolonged exercise in a temperate environment does not elicit a klotho response in either group. In contrast, despite lower resting klotho levels, the older men showed a similar exercise-induced increase in serum klotho response as their younger counterparts.

Circulating small extracellular vesicles increase after an acute bout of moderate-intensity exercise in pregnant compared to non-pregnant women

The physiological and molecular mechanisms linking prenatal physical activity and improvements in maternal–fetal health are unknown. It is hypothesized that small extracellular vesicles (EVs, ~ 10–120 nm) are involved in tissue cross-talk during exercise. We aimed to characterize the circulating small EV profile of pregnant versus non-pregnant women after an acute bout of moderate-intensity exercise. Pregnant (N = 10) and non-pregnant control (N = 9) women performed a single session of moderate-intensity treadmill walking for 30 min. Plasma was collected immediately pre- and post-exercise, and small EVs were isolated by differential ultracentrifugation. EV presence was confirmed by western blotting for the small EV proteins TSG-101 and flottilin-1. Small EVs were quantified by size and concentration using nanoparticle tracking analysis and transmission electron microscopy. All EV fractions were positive for TSG-101 and flotillin-1, and negative for calnexin. Mean vesicle size at baseline and percent change in size post-exercise were not different between groups. At baseline, pregnant women had higher levels of small EVs compared to controls (1.83E+10 ± 1.25E+10 particles/mL vs. 8.11E+09 ± 4.04E+09 particles/mL, respectively; p = 0.032). Post-exercise, small EVs increased significantly in the circulation of pregnant compared to non-pregnant women after correcting for baseline values (64.7 ± 24.6% vs. − 23.3 ± 26.1%, respectively; F = 5.305, p = 0.035). Further research is needed to assess the functional roles of exercise-induced small EVs in pregnancy.

Internalized weight bias is associated with perceived exertion and affect during exercise in a sample with higher body weight.

ObjectiveFor individuals with overweight/obesity, internalized weight bias (IWB) is linked to low physical activity (PA). This study used a laboratory‐based paradigm to test the hypothesis that IWB moderates the association between heart rate (HR) and perceived exertion and affect during PA.MethodsParticipants with overweight/obesity completed 30‐min of supervised moderate‐intensity treadmill walking (65%–75% of age‐predicted maximal HR). Body Mass Index (BMI) and Weight Bias Internalization Scale were assessed at baseline. HR was monitored every minute; perceived exertion and affect were assessed every 5 min. Linear mixed models were employed with random effects of time and participant.ResultsThe sample (n = 59; 79.7% female, 91.5% white) had an average BMI = 32.1 kg/m2 (SD: 3.3), and age = 47.1 (SD: 10.3) years. There was a main effect of IWB on perceived exertion (greater IWB was associated with greater perceived exertion during exercise; p < 0.001). There was an interaction of IWB and HR on affect (B = −0.01, p < 0.01). For individuals with high IWB, HR elevations were associated with a negative affective response during exercise. For individuals with low IWB, HR elevations were associated with increased positive affect during PA.ConclusionsFindings indicate that among individuals of higher body weight, IWB is associated with reporting higher perceived exertion during 30 min of moderate intensity PA. IWB moderated the relationship between increasing HR during exercise and affect. Among individuals with overweight/obesity who report IWB, the initial experience of PA may be harder and more unpleasant, with lasting implications for the adoption of PA.

Dose-Response Effects of Acute Aerobic Exercise Duration on Cognitive Function in Patients With Breast Cancer: A Randomized Crossover Trial.

ObjectiveTo examine the differential effects of acute exercise duration on domains of executive function and processing speed in patients with breast cancer.MethodsParticipants (N = 48, Mage = 56.02 ± 10.99) completed two sessions in counterbalanced order: moderate-intensity treadmill walking and sitting. Participants were also randomized to one of three duration conditions: 10 (n = 15), 20 (n = 16), or 30 (n = 17) min, reflecting the length of time spent walking and sitting. Immediately before and after each session, women completed a battery of cognitive tasks (e.g., inhibition, cognitive flexibility, spatial working memory, and processing speed).ResultsWithin- and between-subjects repeated-measures analyses of variance revealed time by condition interactions on both processing speed (p = 0.02) and spatial working memory (ps < 0.07), such that women demonstrated improved cognitive functioning regardless of the time spent walking. There were also several moderately sized three-way (e.g., time by condition by duration) interactions driven by declines in cognitive functioning after sitting on cognitive flexibility in the 10 (d = -0.96) and 30-min (d = -0.52) groups and inhibition in the 20-min group (d = 0.75). On the processing speed task, women performed significantly faster after walking compared with after sitting in the 20-min group (d = -0.24).ConclusionsFor select cognitive domains, walking anywhere from 10 to 30 min is associated with significant benefits. Our findings suggest the need for further research into the mechanisms and dose–response relationships between acute exercise and cognition as well as how such acute bouts may be accumulated for larger, lasting cognitive benefits after breast cancer.Clinical Trial Registrationwww.ClinicalTrials.gov, identifier NCT04255225

Effect Of Postural Control And Exertion On Dynamic Visual Acuity In Collegiate Athletes.

Dynamic visual acuity (DVA) requires visuo-perceptual processing to resolve the critical details of a target in motion. Athletes demonstrate superior DVA performance compared to non-athletes in a seated position. PURPOSE: To investigate the effects of different postures and exertion levels on DVA in athletes. METHODS: Varsity rugby players (n=10; female=6; age=20.4yrs ±1.4) without recent concussion (˃ 2 years) and/or vestibular-ocular abnormalities were included. DVA was assessed using a custom program (moV& V&MP, University of Waterloo, Ontario) displayed on a 55” LCD monitor at a viewing distance of 4m. The program presented a randomly (RW) or horizontally (H) moving letter ‘E’ target facing left/right/up/down. Participants had to correctly identify the orientation of the target with a keypad as it progressively reduced in size. DVA was scored as the log of the minimum angle of resolution (LogMAR), of the smallest target correctly identified (i.e., low score = better DVA). Participants completed one RW and H trial at a speed of 2.31m/s (30°/s) during four conditions: seated; standing; and treadmill walking at low (85-100 beats per minute [bpm]) and moderate (115-130bpm) intensities. RESULTS: The difference in LogMAR scores from the seated condition were calculated for each of the other conditions. There were no interaction effects of target motion and posture (F=1.02, p=.382), and no main effect of target motion (F=0.30, p=.598). However, there was a trending main effect of posture (Stand: 0.00 vs. Walk Low: -0.14 vs. Walk Mod: 0.04 p= .056, f= 0.25). These findings indicate that athletes’ DVA improved from seated during moderate intensity treadmill walking more so than both standing and low-intensity treadmill walking. CONCLUSION: Athletes appear to have improved DVA in sport-specific conditions of greater postural and exertional demands. Therefore, sport training experience may enhance visuo-perceptual skills. These findings may inform clinicians to consider the assessment of DVA with progressive, dynamic contexts for rehabilitation, such as for return to sport from concussion.

The dosing of aerobic exercise therapy on experimentally-induced pain in healthy female participants

Knowledge of efficacious dosing respective to exercise type and pain condition is extremely limited in the literature. This study aimed to determine the impact of dose of moderate intensity treadmill walking on experimentally-induced pain in healthy human participants. Forty females were divided into 4 groups: control (no exercise), low dose exercise (3×/wk), moderate dose exercise (5×/wk) or high dose exercise (10×/wk). Over a 7-day period, subjects performed treadmill walking during assigned exercise days. Both qualitative and quantitative measures of pain were measured at baseline, during the trial, and 24 hrs post-final intervention session via sensitivity thresholds to painful thermal and painful pressure stimulation. Significant effects of treatment were found post-intervention for constant pressure pain intensity (p = 0.0016) and pain unpleasantness ratings (p = 0.0014). Post-hoc tests revealed significant differences between control and moderate and control and high dose groups for constant pressure pain intensity (p = 0.0015), (p = 0.0094), respectively and constant pressure pain unpleasantness (p = 0.0040), (p = 0.0040), respectively. Moderate and high dose groups had the greatest reductions in ratings of pain, suggesting that our lowest dose of exercise was not sufficient to reduce pain and that the moderate dose of exercise may be a sufficient starting dose for exercise-based adjuvant pain therapy.

Acute aerobic exercise effects on cognitive function in breast cancer survivors: a randomized crossover trial

BackgroundMany breast cancer survivors (BCS) report deficits in cognitive function. Physical activity (PA) has been associated with better processing speed and memory in healthy adults and thus may be a useful method for improving cognition in BCS. The purpose of this study was to examine the effects of an acute bout of PA on processing speed and spatial working memory in a sample of BCS.MethodsUsing a repeated measures, crossover design, BCS [N = 27; Mage (SD) = 49.11(8.05)] completed two sessions in counterbalanced order: 30 min of moderate-intensity treadmill walking and 30 min of seated rest. Women completed cognitive tasks immediately before and after each session.ResultsWithin-subjects repeated measures analyses of variance revealed a significant time by session effect for processing speed reaction time [F (1,25) = 5.02, p = .03, η2 = 0.17]. This interaction was driven by significantly reduced reaction time (e.g., faster response) post-exercise and no change post-rest. Further between-subjects analyses indicated a significant time by session by moderate to vigorous physical activity (MVPA) split [F (1,25) = 5.23, p = .03, η2 = 0.17], such that women who engaged in ≥45 min of average daily MVPA reduced their reaction time post-exercise (p = .01) and increased RT post-rest (p = .06). Time by session effects for spatial working memory 3-item accuracy and 4-item reaction time trended towards significance, p = 0.08 and p = 0.10, respectively, again driven by better performance post-exercise.ConclusionsThe moderate effect of acute exercise on domains of memory and processing speed in BCS is encouraging. Cancer-related cognitive impairment remains largely misunderstood; however, the results from the present study offer preliminary evidence for the positive relationship between acute exercise and cognition in BCS.Trial registrationClinicalTrials.gov NCT02592070. Registered 30 October 2015. Retroactively registered.

Acute effects of active breaks during prolonged sitting on subcutaneous adipose tissue gene expression: an ancillary analysis of a randomised controlled trial

Active breaks in prolonged sitting has beneficial impacts on cardiometabolic risk biomarkers. The molecular mechanisms include regulation of skeletal muscle gene and protein expression controlling metabolic, inflammatory and cell development pathways. An active communication network exists between adipose and muscle tissue, but the effect of active breaks in prolonged sitting on adipose tissue have not been investigated. This study characterized the acute transcriptional events induced in adipose tissue by regular active breaks during prolonged sitting. We studied 8 overweight/obese adults participating in an acute randomized three-intervention crossover trial. Interventions were performed in the postprandial state and included: (i) prolonged uninterrupted sitting; or prolonged sitting interrupted with 2-minute bouts of (ii) light- or (iii) moderate-intensity treadmill walking every 20 minutes. Subcutaneous adipose tissue biopsies were obtained after each condition. Microarrays identified 36 differentially expressed genes between the three conditions (fold change ≥0.5 in either direction; p < 0.05). Pathway analysis indicated that breaking up of prolonged sitting led to differential regulation of adipose tissue metabolic networks and inflammatory pathways, increased insulin signaling, modulation of adipocyte cell cycle, and facilitated cross-talk between adipose tissue and other organs. This study provides preliminary insight into the adipose tissue regulatory systems that may contribute to the physiological effects of interrupting prolonged sitting.

The Experimental Effects of Acute Exercise on Long-Term Emotional Memory.

Emerging work suggests that acute, moderate-intensity aerobic exercise may help to subserve episodic memory of neutral stimuli. Less investigated, however, is whether acute exercise is associated with enhanced memory recognition of emotional stimuli, which was the purpose of this experiment. A parallel-group randomized controlled experiment was employed. Participants (mean age = 20 yr) were randomized into an exercise (n = 17) or control group (n = 17). The exercise group engaged in a 15-min bout of moderate-intensity treadmill walking. Emotional memory recognition was assessed via images from the International Affective Picture System, including assessments of varying degrees of valence and arousal. Memory recognition was assessed at 1 day, 7 days, and 14 days post-memory encoding. We observed a significant main effect for time (F(2) = 104.2, p < 0.001, η2p = 0.77) and a significant main effect for valence–arousal classification (F(4) = 21.39, p < 0.001, η2p = 0.40), but there was no significant time by group interaction (F(2) = 1.09, p = 0.34, η2p = 0.03), classification by group interaction (F(4) = 0.12, p = 0.97, η2p = 0.01), time by classification interaction (F(8) = 1.78, p = 0.08, η2p = 0.05), or time by classification by group interaction (F(8) = 0.78, p = 0.62, η2p = 0.02). In conclusion, emotional memory recognition decreased over the 14-day follow-up period and this rate of memory decay was not altered by acute moderate-intensity exercise engagement. We discuss these findings in the context of exercise intensity and the temporal effects of exercise.

Cerebral Blood Flow Characteristics Responses Following Acute Aerobic Exercise in Individuals with and without Down Syndrome

Individuals with Down Syndrome (DS) commonly experience low to moderate levels of cognitive impairment and are at a high risk of developing dementia and Alzheimer's diseases (AD). Reduced cerebral blood flow (CBF) and altered CBF characteristics have been observed in the aging population without DS and has shown to have detrimental effects on cerebral microvasculature, which may increase the risk of developing dementia and AD. However, differences in CBF and its characteristics between individuals with and without DS and its response to exercise have not been studied.PurposeTo examine the differences in CBF and its characteristics following a 20‐minute bout of moderate intensity walking in individuals with and without DS.MethodsThirty‐eight young (DS=19, Age=25 yrs) individuals with and without DS participated in this study. Changes in mean middle cerebral artery velocity (mMCAv), mMCAv characteristics (pulsatility index (PI), resistance index (RI)) and hemodynamic variables were measured before, immediately post and 30‐minute post exericse.ResultsBaseline hemodynamics, systolic blood pressure (BP), diastolic BP, mean arterial pressure (MAP), heart rate (HR) and mMCAv were not different between the DS and control group (p&gt;0.05 for all). Neither group showed changes in mMCAv after moderate intensity treadmill walking exercise (p&gt;0.05). However, the DS group exhibited significantly higher PI and RI at all time points when compared to controls (p&lt;0.05 for both).ConclusionsOur results demonstrate that CBF was not altered in individuals with DS at rest and following moderate intensity exercise and was not different from that of controls. However, higher PI and RI in DS group may be associated with reduced distal cerebral perfusion and microvascular damage in individuals with DS. DS (N = 19) Control (N = 19) Baseline Immediate post EX 30‐minute post EX Baseline Immediate post EX 30‐minute post EX SBP (mmHg) 122±14 126±11* 121±13 120±10 130±12* 121±11 DBP (mmHg) 69±9 75±8* 70±9 72±6 81±8* 74±9 MAP (mmHg) 93±10 98±8* 94±9 94±7 103±7* 96±8 mMCAv (cm/s) 64.3±14.9 62.8±13.9 60.8±14.6 69.4±13.1 69.8±14.8 69.6±14.1 PI‡ 0.97±0.14 1.04±0.19 1.02±0.14 0.87±0.12 0.89±0.15 0.86±0.14 RI‡ 0.60±0.05 0.61±0.06 0.61±0.05 0.56±0.05 0.56±0.05 0.55±0.05 Significant group difference, Significant time difference from the baseline. Mean ± SD, Significance level, p &lt; 0.05 This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Intermittent Walking has Similar Effects on 24-Hour Glycemia as a Calorically Equivalent Continuous Walk in Older Adults

Older adults spend more time engaged in sedentary behavior (SB) than any other segment of the population. Interrupting sedentary time with short bouts of walking improves 24-hour glycemic control compared to uninterrupted sitting. However, it is not known if short-walking bouts are as beneficial to 24-hour glycemia as a single bout of continuous exercise. PURPOSE: To compare the effectiveness of multiple, short intermittent walking bouts and one, calorically equivalent continuous bout of walking on 24-hour glycemia in older adults. METHODS: Healthy, overweight/obese older adults (N=18, 67 ± 5 y, BMI = 32.2 ± 4,3 kg/m2) completed two, 24h conditions in a whole room indirect calorimeter; 1) Intermittent walking (IW): 1.5 min of moderate intensity treadmill walking (36 min total) every 30 minutes and 2) continuous walking (CW): 36 min continuous, moderate intensity treadmill walking performed in the morning (~8AM). Outside of the prescribed walking times, subjects remained in SB for the remainder of the waking day. Continuous glucose monitoring was used to measure interstitial glucose concentrations every 5 minutes. Energy and macronutrient intake was standardized between conditions. RESULTS: 24-hour energy expenditure (2257 ± 329 vs. 2165 ± 302 kcal, mean ± SD) and RQ (0.84 ± 0.03 vs. 0.84 ± 0.03) were similar during IW and CW, respectively. Peak postprandial glucose following dinner was lower (p<0.05) during IW (120.4 ± 10.7 mg/dl) compared to CW (135.3 ± 15.3 mg/dl). No differences were observed in any other 24 hour glycemia variables, including 24 hour area under the glucose curve (IW = 154862 ± 12724 mg/dl, CW = 158096 ± 15156 mg/dl), glycemic variability (standard deviation of 24 hour glucose concentrations) (IW = 12.2 ± 4.4 mg/dl, CW = 12.2 ± 4.2 mg/dl), and peak postprandial glucose concentrations following breakfast (IW = 144.0 ± 22.7 mg/dl, CW = 144.8 ± 27.2 mg/dl) and lunch (IW = 137.9 ± 17.1 mg/dl, CW = 139.2 ± 17.8 mg/dl). CONCLUSION: These results suggest IW had similar effects as CW on 24-hour glycemia, although the postprandial glucose response to meals consumed later in the day may be lower with IW. IW may improve cardiometabolic health in older adults.

The Effect Of Morning Or Evening Exercise On Cardiovascular Fitness And Body Weight

PURPOSE: To compare the effect of 8 weeks of morning exercise or evening exercise on cardiovascular fitness and body composition in healthy women. METHODS: Fifty-five participants were randomized to either a morning exercise group (AM) (25.3±4.1 yrs; 25.2±4.7 kg/m2; 37.9±7.6 %BF) or an evening exercise group (PM) (25.4±6.7 yrs; 23.5±3.9 kg/m2; 34.1±6.1 %BF). The AM group completed exercise between 6:30-9:30am and the PM group between 6:30-9:30pm, both for 4 days per week (3 days supervised), 45 minutes per session, and for 8 weeks. All participants followed an exercise program of moderate-intensity treadmill walking (40-59% heart rate reserve [HRR]) and progressed to include vigorous-intensity exercise (60-89% HRR). Cardiovascular fitness was determined using a maximal treadmill protocol and indirect calorimetry. Body weight/composition was determined using a digital scale and dual-energy x-ray absorptiometry (DXA). RESULTS: Eighty-two percent of participants completed the study; 21 (78%) from the AM group and 25 (86%) from the PM group, with 94.75% of the prescribed exercise sessions completed. Using intent-to-treat analysis, there was not a group*period interaction for V02peak or time-to-completion during the treadmill test (ps>0.05); however, with groups combined, time-to-completion during the fitness test significantly improved (F=6.66; p=0.013). For completers in the AM group, 76% gained weight while 36% gained weight in the PM group. For completers, body weight increased by 0.79±1.16 kg in the AM group (F=5.05; p=0.0361) and decreased by 0.21±1.46 kg in the PM group. Intent-to-treat analysis showed a significant group*period interaction (F=5.12; p=0.029). This trend persisted with control of baseline body weight (F=5.02; p=0.0301). However, there was not a significant group*period interaction for total body fat (g) or fat-free mass (g) (ps>0.05). CONCLUSIONS: Eight weeks of exercise may improve exercise performance but does not appear to be a function of time of day of exercise. However, these results suggest the possibility that evening exercise may be slightly superior for body weight maintenance. As these differences are small and body composition did not differ between groups, caution should be used when interpreting these data; however, additional research may be warranted.

Effect of frequent interruptions of prolonged sitting on self-perceived levels of energy, mood, food cravings and cognitive function.

BackgroundWhile physical activity has been shown to improve cognitive performance and well-being, office workers are essentially sedentary. We compared the effects of physical activity performed as (i) one bout in the morning or (ii) as microbouts spread out across the day to (iii) a day spent sitting, on mood and energy levels and cognitive function.MethodsIn a randomized crossover trial, 30 sedentary adults completed each of three conditions: 6 h of uninterrupted sitting (SIT), SIT plus 30 min of moderate-intensity treadmill walking in the morning (ONE), and SIT plus six hourly 5-min microbouts of moderate-intensity treadmill walking (MICRO). Self-perceived energy, mood, and appetite were assessed with visual analog scales. Vigor and fatigue were assessed with the Profile of Mood State questionnaire. Cognitive function was measured using a flanker task and the Comprehensive Trail Making Test. Intervention effects were tested using linear mixed models.ResultsBoth ONE and MICRO increased self-perceived energy and vigor compared to SIT (p < 0.05 for all). MICRO, but not ONE, improved mood, decreased levels of fatigue and reduced food cravings at the end of the day compared to SIT (p < 0.05 for all). Cognitive function was not significantly affected by condition.ConclusionsIn addition to the beneficial impact of physical activity on levels of energy and vigor, spreading out physical activity throughout the day improved mood, decreased feelings of fatigue and affected appetite. Introducing short bouts of activity during the workday of sedentary office workers is a promising approach to improve overall well-being at work without negatively impacting cognitive performance.Trial registration NCT02717377, registered 22 March 2016.

Vitamin D supplementation affects the IGF system in men after acute exercise

ObjectiveContradictory data between the Insulin-Like Growth Factor System (IGF) system and exercise may be due to alteration in IGF binding proteins. Vitamin D (D) deficiency has been related to muscle weakness and Insulin Like Growth Factor Binding Protein 3 (IGFBP3). A Vit. D and acute exercise merge is proposed to modify the IGF system. DesignD insufficient and deficient men (39.0±8.6yo with serum D (25OH D) 20.0±7.7ng/mL) did 1h of stretching (ST), aerobic (AB), and resistance (RT) exercises, before and after 28d of 4000IU/d Vit. D3 (D, n=6) or Placebo (P, n=7). ST, a time/attention control visit, interchanged unreceptive movements. AB was moderate intensity treadmill walking. RT rotated moderate strength 50% 1-RM repetitions (15, 10) of squat, bench press, leg press, and lat pull down. Serum Total IGF1 (TIGF1), Insulin Like Growth Factor Binding Protein 1 (IGFBP1), and IGFBP3 were measured before (T1, fasting), immediately after (T2), and 2h post (T3) exercise. ResultsAfter ST, IGFBP3 was greater in the D group at T2 (2948, 2130ng/mL; p<0.03) and T3 (3087, 2212; p<0.02). During RT, TIGF1 decreased in the Placebo (P) group from T1 to T3 (151.4, 107.3ng/mL; p<0.05), while IGFBP1 increased in the D group from T1 to T3 (26.5, 96.2ng/mL; p<0.05). RT IGFBP3 was greater at T1, T2, and T3 in the D group (2932.5, 2110.7; p<0.03), (3163.9, 2392.5; p<0.04), and (3355.3, 2353.1; p<0.01). In AB, IGFBP3 was greater in the D group at T2 (3128.6, 2226.3.0; p<0.04) and T3 (2949.7, 2135.1; p<0.05). ConclusionD supplementation amplified IGFBP3 after low or moderate activity which may increase the delivery of IGF1 to tissues. Resistance exercise with D not only increased IGFBP3 and IGFBP1 levels but also conserved TIGF1 levels, possibly shifting the IGF system for enriched muscle well-being.

Intensity of treadmill walking exercise on acute mood symptoms in persons with multiple sclerosis

ABSTRACTBackground/Objectives: An acute bout of moderate-intensity treadmill walking exercise has previously been associated with improvements in overall mood disturbance and vigor, without worsening fatigue, among persons with multiple sclerosis (MS).This study examined the effects of light-, moderate-, and high-intensity bouts of treadmill walking exercise on immediate and delayed mood states in MS. Design: This was a within-subjects, randomized, and counter-balanced study. Methods: 23 women and 1 man with MS undertook 20-minute bouts of light-, moderate-, and high-intensity treadmill walking, and seated quiet rest. Participants completed the profile of mood states (POMS) questionnaire before, immediately after, and 45 minutes after each condition. Total mood disturbance (TMD) and six subscales of the POMS were analyzed using 2-way, repeated-measures analysis of variance (ANOVA). Results: There was a significant condition-by-time interaction on TMD scores () and vigor scores (). The moderate-intensity treadmill walking yielded the largest improvements in TMD and vigor immediately post-condition (p < .05). These improvements were no longer significant at 45 minutes post-condition (p > .05). Conclusion: TMD and vigor improved immediately after moderate-intensity walking, but the changes dissipated over time. Fatigue did not worsen after any of the walking conditions. These results indicate that an acute bout of moderate-intensity walking may help with mood management in persons with MS, without worsening fatigue.

Is Cognitive Function Impaired while Working in a Climate Chamber at 30°C in Fire Fighters?

Firefighting requires cognitive abilities, such as attention, vigilance, spatial awareness, decision making, and air management, under extreme life-threatening working conditions. To date, cognitive function during exertional heat stress in firefighters has been conducted utilizing simple mental performance tasks, such as reaction time, or lacking cognitive assessments while core temperature was increasing to detect any changes. PURPOSE: The purpose of this study was to examine the effects of thermal stress on various aspects of cognitive function during moderate-intensity treadmill walking. METHODS: Nineteen fire fighters were tested (age 35.6 ± 8.7 years, BMI 27.3 ± 3.2 kg.m-1, body fat 16.7 ± 5.8 %, VO2peak = 45.2 ± 5.5 mL.kg-1.min-1). Core temperature, skin temperature, and heart rate were continuously monitored and 5 mL.kg-1 of water was provided throughout the protocol. Firefighters walked on a motorized treadmill at 4.5 km.h-1 and 2.5% grade, in a climate chamber controlled at 30 °C and 50% relative humidity for 84.3 ± 13.4 min. Cognitive function was tested using the CANTABeclipse battery (spatial working memory - SWM, reaction time - RTI, rapid visual information processing - RVP, spatial span - SSP, and paired associates learning - PAL) at baseline, immediately following completion of exercise, and after attaining a hand and forearm immersion recovery core temperature of 37.8 °C, while SSP and PAL were also evaluated during exercise when core temperatures of 37.8, 38.5, and 39.0 °C were attained. RESULTS: Compared to baseline, post-tests for RVP revealed improvements in correct rejections (262.9 ± 8.6 vs 267.2 ± 5.9 rejections; p < 0.05), latency (380.3 ± 83.7 vs 334.9 ± 42.2 ms; p < 0.05), and simple reaction time (286.8 ± 35.1 vs 270.0 ± 31.2 ms; p < 0.05), while performance on the PAL test showed significantly more errors during the final level (5.7 ± 5.5 vs 9.6 ± 8.7 errors; p < 0.05) when core temperature reached 38.5°C. CONCLUSIONS: Taken together, it appears that visual memory and new learning is impaired when core temperature reaches 38.5°C without decrements in spatial information, sustained attention, or working memory capacity when the average rate of increase in core temperature is 0.87 ± 0.24 °C.h-1. This research was supported by the Workers Compensation Board of Manitoba.