Effect of chronic stress on running wheel activity in mice

Acute and chronic stress have been reported to have differing effects on physical activity in rodents, but no study has examined a chronic stress protocol that incorporates stressors often experienced by rodents throughout a day. To examine this, the effects of the Unpredict- able Chronic Mild Stress (UCMS) protocol on voluntary running wheel activity at multiple time points, and/or in response to acute removal of chronic stress was determined. Twenty male Balb/c mice were given access and accustomed to running wheels for 4 weeks, after which they were randomized into 2 groups; exercise (EX, n = 10) and exercise with chronic stress using a modified UCMS protocol for 7 hours/day (8:00 a.m.-3:00p.m.), 5 days/week for 8 weeks (EXS, n = 10). All mice were given access to running wheels from approximately 3:30 p.m. to 7:30 a.m. during the weekday, however during weekends mice had full-time access to running wheels (a time period of no stress for the EXS group). Daily wheel running distance and time were recorded. The average running distance, running time, and work each week- day was significantly lower in EXS compared to EX mice, however, the largest effect was seen during week one. Voluntary wheel running deceased in all mice with increasing age; the pattern of decline appeared to be similar between groups. During the weekend (when no stress was applied), EXS maintained higher distance compared to EX, as well as higher daily distance, time, and work compared to their weekday values. These results indicate that mild chronic stress reduces total spontaneous wheel running in mice during the first week of the daily stress induction and maintains this reduced level for up to 8 consecutive weeks. How- ever, following five days of UCMS, voluntary running wheel activity rebounds within 2–3 days

Exercise Training Prevents the Perivascular Adipose Tissue-induced Aortic Dysfunction with Metabolic Syndrome

The aim of the study was to determine the effects of exercise training on improving the thoracic perivascularadipose tissue (tPVAT) phenotype (inflammation, oxidative stress, and proteasome function) in metabolic syn-drome and its subsequent actions on aortic function.Methods:Lean and obese (model of metabolic syndrome) Zucker rats (n=8/group) underwent 8-weeks ofcontrol conditions or treadmill exercise (70% of max speed, 1 h/day, 5 days/week). At the end of the inter-vention, the tPVAT was removed and conditioned media was made. The cleaned aorta was attached to a forcetransducer to assess endothelium-dependent and independent dilation in the presence or absence of tPVAT-conditioned media. tPVAT gene expression, inflammatory /oxidative phenotype, and proteasome function wereassessed.Results:The mainfindings were that Ex induced: (1) a beige-like, anti-inflammatory tPVAT phenotype; (2) agreater abundance of•NO in tPVAT; (3) a reduction in tPVAT oxidant production; and (4) an improved tPVATproteasome function. Regarding aortic function, endothelium-dependent dilation was greater in exercised leanand obese groups vs. controls (p \u3c 0.05). Lean control tPVAT improved aortic relaxation, whereas obese controltPVAT decreased aortic relaxation. In contrast, the obese Ex-tPVAT increased aortic dilation, whereas the leanEx-tPVAT did not affect aortic dilation.Conclusion:Overall, exercise had the most dramatic impact on the obese tPVAT reflecting a change towards anenvironment with less oxidant load, less inflammation and improved proteasome function. Such beneficialchanges to the tPVAT micro-environment with exercise likely played a significant role in mediating the im-provement in aortic function in metabolic syndrome following 8 weeks of exercise

Full-Body Photobiomodulation Therapy Is Associated with Reduced Sleep Durations and Augmented Cardiorespiratory Indicators of Recovery

Research is emerging on the use of Photobiomodulation therapy (PBMT) and its potential for augmenting human performance, however, relatively little research exists utilizing full-body administration methods. As such, further research supporting the efficacy of whole-body applications of PBMT for behavioral and physiological modifications in applicable, real-world settings are warranted. The purpose of this analysis was to observe cardiorespiratory and sleep patterns surrounding the use of full-body PBMT in an elite cohort of female soccer players. Members of a women’s soccer team in a “Power 5 conference” of the National Collegiate Athletic Association (NCAA) were observed across one competitive season while wearing an OURA Ring nightly and a global positioning system (GPS) sensor during training. Within-subject comparisons of cardiorespiratory physiology, sleep duration, and sleep composition were evaluated the night before and after PBMT sessions completed as a standard of care for team recovery. Compared to pre-intervention, mean heart rate (HR) was significantly lower the night after a PBMT session (p = 0.0055). Sleep durations were also reduced following PBMT, with total sleep time (TST) averaging 40 min less the night after a session (p = 0.0006), as well as significant reductions in light sleep (p = 0.0307) and rapid eye movement (REM) sleep durations (p = 0.0019). Sleep durations were still lower following PBMT, even when controlling for daily and accumulated training loads. Enhanced cardiorespiratory indicators of recovery following PBMT, despite significant reductions in sleep duration, suggest that it may be an effective modality for maintaining adequate recovery from the high stress loads experienced by elite athletes

Role of Chronic Stress and Exercise on Microvascular Function in Metabolic Syndrome

Purpose—The present study examined the effect of unpredictable chronic mild stress (UCMS) on peripheral microvessel function in healthy and metabolic syndrome (MetS) rodents, and whether exercise training could prevent the vascular dysfunction associated with UCMS. Methods—Lean and obese (model of MetS) Zucker rats (LZR; OZR) were exposed to 8 weeks of UCMS, exercise (Ex), UCMS+Ex, or control conditions. At the end of the intervention, gracilis arterioles (GAs) were isolated and hung in a pressurized myobath to assess endotheliumdependent (EDD) and -independent (EID) dilation. Levels of nitric oxide (NO) and reactive oxygen species (ROS) were measured through DAF-FM and DHE staining, respectively. Results—Compared to LZR controls, EDD and EID was lower (p=0.0001) in LZR-UCMS. The OZR-Ex group had a higher EDD (p=0.0001) and EID (p=0.003), compared to OZR-Controls; whereas only a difference in EDD (p=0.01) was noted between LZR-Control and LZR-Ex groups. Importantly, EDD and EID were higher in the LZR (p=0.0001; p=0.02) and OZR (p=0.0001; p=0.02) UCMS+Ex groups compared to UCMS alone. Lower NO bioavailability and higher ROS were noted in the LZR-UCMS group (p=0.0001), but not OZR-UCMS, compared to controls. Ex and UCMS-Ex groups had higher NO bioavailability (p=0.0001) compared to control and UCMS groups, but ROS levels remained high. Conclusions—The comorbidity between UCMS and MetS does not exacerbate the effects of one another on GA EDD responses, but does lead to the development of other vasculopathy adaptations, which can be partially explained by alterations in NO and ROS production. Importantly, exercise training alleviates most of the negative effects of UCMS on GA function

Effect of chronic stress on running wheel activity in mice - Table 1

<p>Effect of chronic stress on running wheel activity in mice</p> - Table

Body mass over the 8 weeks of training in mice subjected to either unpredictable chronic mild stress (EXS) or no stress (EX).

<p>Week -4 through 0 represents the pre-intervention period with week 0 as the last weight of pre-training. Repeated measures ANOVA (rmANOVA), EXS increased weight significantly more than EX (interaction main effect, p<0.005); # signifies Fisher’s PLSD p<0.05 compared to EX.</p

Weekday (EX and EXS) and weekend (EX-WE and EXS-WE) values for the total daily averages of (A) run-time, (B) distance, and (C) energy expenditure, i.e. work (min*km*kg).

<p>Two-way ANOVA (stress x time of week), post hoc testing using Fisher’s PLSD, * p<0.05, # denotes difference between weekday and weekend within the same stress group (i.e. EX vs EX-WE or EXS v EXS-WE) p<0.05.</p

Average weekend wheel activity over the 8-week study for (A) run time, (B) distance, and (C) expenditure.

<p>Significant group by time interaction, and significant group difference (p<0.05) are represented in each graph.</p

Average weekday wheel activity over the 8-week study for EX and EXS for (A) run time, (B) run distance, and (C) energy expenditure (i.e. work).

<p>Data for EX group in week 3 (box with horizontal hash marks) have been imputed based on the average between week two and four values from EX group. Repeated measures ANOVA</p