Prior Exercise Research Articles

Effects of Prior Aerobic Exercise on Flow Mediated Dilation Responses to Prolonged Sitting in Healthy Men

Effects of Prior Aerobic Exercise on Flow Mediated Dilation Responses to Prolonged Sitting in Healthy Men

Prior Acute Resistance Exercise Enhances Postprandial Fat Oxidation in Response to a High-Fructose Meal

Prior Acute Resistance Exercise Enhances Postprandial Fat Oxidation in Response to a High-Fructose Meal

Prior treadmill exercise promotes resilience to vicarious trauma in rats

BackgroundPost-traumatic stress disorder (PTSD) is a serious psychological condition, which can develop both from physically experiencing and also from witnessing traumatic events. There is evidence that physical exercise can have a positive impact on the symptoms of PTSD. Relevant to this, in our previous pre-clinical work, beneficial effects of treadmill exercise were reported on PTSD-like behaviors in a social defeat paradigm, a rat model of direct physical trauma. However, the role of exercise on vicariously acquired PTSD-like phenotype was not examined. ObjectiveIn this study, we utilized a rodent PTSD model, which mimics both the physical as well as the witness experience of trauma, and examined the impact of moderate treadmill exercise in mitigating vicariously acquired PTSD-like behaviors in rats. MethodsOur PTSD model is a modified social defeat paradigm, which involves aggressive encounters between a large Long-Evans male rat (resident) and a smaller Sprague-Dawley male rat (intruder), resulting in intruder social defeat. The cage mate of the intruder is positioned to witness intruder defeat. Rats were grouped as control (CON), social defeat (SD), exercise (EX), trauma witness (TW), and exercise prior to trauma witness (EX-TW). After acclimatization for 7days, the exercised groups were subjected to a daily 30-min treadmill exercise regimen for 14days. On day 21, the SD group was exposed for 7days of social defeat, while the TW groups witnessed social defeat. On days 28–34, behavioral and cognitive tests including short-term (STM) and long-term (LTM) memory function, anxiety- and depression-like behaviors were conducted. ResultsTW and SD rats demonstrated the highest levels of anxiety- and depression-like behaviors, while EX-TW rats did not exhibit anxiety- and depression-like behaviors. TW and SD rats showed no impairments in STM. However, TW and SD rats showed impairments in LTM, and exercise rescued LTM impairments in EX-TW rats. ConclusionsThis study demonstrates that rats subjected to direct experience or witness of social defeat exhibited PTSD-like behaviors, while moderate treadmill exercise prevented trauma witness-induced behavioral impairments. These studies have important translational value suggesting that prior treadmill exercise might provide resilience to stressful stimuli and perhaps mitigate the witnessing effects of traumatic events.

Prior Exercise Training Alters the Response of White and Brown Adipose Tissue to Cold Stress

Brown adipose tissue is a thermogenic tissue bed that produces heat in conditions of cold environmental temperatures. While possessing much lower oxidative capacity than brown adipose tissue, recent findings have suggested that exercise training can increase the thermogenic capacity of white adipose tissue. What is not known is if exercise training can alter the response of an animal to cold stress. To address this question, male C57BL/6 mice were subject to either exercise training by voluntary wheel running (EX) or a sedentary (SED) intervention for 12 days. EX mice ran approximately 6km/day, which led to decreased body weight and increased glucose tolerance, while maintaining a similar pattern of food intake to SED. Mice were then further divided into groups that would be kept at room temperature (22°C) or a cold challenge of 4°C for 48‐hrs, thus we examined four groups in this study; (i) SED kept at room temperature (SRT), (ii) exercise trained kept at room temperature (EXRT), (iii) SED kept at 4°C (SC), and (iv) EX kept at 4°C (EXC). Rectal temperatures (Tb) of SC and EXC were lower than that of SRT and EXRT, and the initial drop in Tb of EXC was less than that observed in the SC 2‐hours following the start of the cold, however this difference was not maintained throughout the rest of the cold exposure. 48‐hrs of cold exposure led to reductions in body weight and epididymal and subcutaneous adipose tissue mass in the SED but not EX mice. Conversely, interscapular brown adipose tissue mass was increased following cold exposure in previously EX but not SED animals Taken together, our data demonstrates a unique effect of prior exercise on altering the response of adipose tissue to cold stress.Support or Funding InformationD.C.W. is a Tier II Canada Research Chair. This work was funded by an NSERC Discovery Grant to D.C.W.

Prior Treadmill Exercise Promotes Resilience in Traumatized Rats

Post‐traumatic stress disorder (PTSD) is a serious psychological condition induced by experiencing traumatic events. Interestingly, PTSD can be acquired not only from directly experiencing traumatic events but also from witnessing such events. Treatment and prevention strategies are limited. Animal studies have provided critical insights. Recently, we published a “Trauma Witness Model” (TWM) of rat and reported that witnessing traumatic events cause PTSD‐like behaviors including anxiety‐ and depression‐like behavior as well as learning‐memory deficits. TWM is a modified social defeat paradigm, which involves aggressive encounters between a large Long‐Evans male rat (resident) and a smaller Sprague‐Dawley male rat (intruder), resulting in intruder social defeat. The cage mate of the intruder designated as trauma witnessing rat (TW), is positioned to witness intruder defeat. Using this model, we examined beneficial role of moderate treadmill exercise in preventing TW‐induced behavioral impairments. Beneficial role of treadmill exercise has been reported in other models of stress. Male Sprague Dawley rats were allocated to five different groups: control (C), social defeat (SD), exercise (Ex), trauma witness (TW), and trauma witness with exercise (TWEx). The two exercised groups, Ex and TWEx, were subjected to a daily 30‐minute treadmill exercise regimen for 14 days. On day 15, the SD group was exposed to 7 days of direct trauma. The trauma witness groups, TW and TWEx, were strategically placed around the cage to witness the SD rats receive social defeat. On day 22, all groups were subjected to behavioral and cognitive tests including short‐term (STM) and long‐term (LTM) memory function, anxiety and depression‐like behaviors. TW and SD had the highest levels of anxiety and depression‐like behaviors compared to the other groups. In addition, TWEx had lower levels of anxiety and depression‐like behaviors compared to TW. STM and LTM remained unchanged. This study demonstrates that treadmill exercise provides resilience to trauma witness in a rodent model.Support or Funding InformationGrant Support: 2R15MH093918‐02

Effect of a single bout of aerobic exercise on high-fat meal-induced inflammation

Background and aimsChronic low-grade inflammation is involved in the development of metabolic disorders including atherosclerosis, type 2 diabetes (T2D) and metabolic syndrome. Aerobic exercise has been shown to be anti-inflammatory and attenuate postprandial blood lipids, however, the effect of exercise on postprandial inflammation remains unclear. The aim of this study was to determine the protective effect of a single bout of aerobic exercise against postprandial lipemia and peripheral blood mononuclear cell (PBMC) inflammation and to evaluate associations with changes in the energy-sensing enzyme, AMP-activated protein kinase (AMPK). Materials and methodsHealthy male subjects (n=12, age=23±2, %Fat=19±2) reported to the laboratory following an overnight fast (12–14h) on two separate occasions for consumption of a high-fat meal (HFM). Participants completed an acute bout of aerobic exercise the afternoon prior to one of the HFM visits. Results and conclusionResults indicate that the single bout of moderate aerobic exercise increased AMPK signaling in PBMCs, as shown by increased phosphorylated acetyl-CoA carboxylase (p-ACC). This may be due to decreases in the AMPK inhibitory kinases PKD and GSK3β. Additionally, prior moderate intensity exercise decreased postprandial lipemia (PPL) and some mediators of the inflammatory pathway, such as p-NF-κB. These findings that acute aerobic exercise improves AMPK and NF-κB signaling in human PBMCs contribute support to the anti-inflammatory roles of exercise.

Engagement in health-promoting behaviors and patient-caregiver interdependence in dyads facing advanced cancer: an exploratory study.

Diet and exercise are important for the wellbeing of people with cancer and their family caregivers. Unfortunately, little is known about their behaviors over time or factors that may influence their engagement in these behaviors. This exploratory study examined the influence of chronic conditions, symptom distress, and perceived social support on exercise and diet behaviors of patients with advanced cancer and their caregivers using the actor-partner interdependence mediation model (APIMeM) and interdependence theory as guiding frameworks. This secondary analysis uses self-report data from a large RCT (N=484 patient-caregiver dyads) at three time points: baseline data was collected within three months of the diagnosis, at 3months post-baseline, and 6months post-baseline. A number of actor effects were observed: patient and caregiver prior exercise and diet were significant predictors of their own future exercise and diet behaviors; more patient-reported social support was associated with less patient exercise; more patient symptom distress was associated with poorer patient diet; and, more caregiver-reported social support was associated with more caregiver exercise and better caregiver diet. Partner effects were also observed: more patient exercise was positively associated with more caregiver exercise; more patient comorbidities were associated with better caregiver diet; more caregiver-reported social support was associated with better patient diet; and, more patient-reported social support was associated with better caregiver diet. Despite the challenges of advanced cancer and caregiving, past exercise and diet behavior remained a significant predictor of future behavior. Other health problems and perceptions of social support within the dyad may exert a positive or negative influence on patient/caregiver diet and exercise.

Acute aerobic exercise hastens emotional recovery from a subsequent stressor.

Despite findings that regular exercise is broadly associated with emotional well-being, more basic research is needed to deepen our understanding of the exercise and emotion connection. This paper examines how acute aerobic exercise in particular influences subjective emotional recovery from a subsequent stressor. Potential mediators and moderators, including level of physical fitness, attentional control, and perseverative negative thinking were explored. All of the participants (n = 95) completed 3 laboratory visits, each including 1 of 3 activities (i.e., cycling, resting, stretching), tests of working memory and attentional control, and an experimental stressor. Self-reported rumination after the stressor and the experience of positive and negative emotions throughout the study were recorded. In this within-subjects paradigm, as expected, higher rumination in response to the stressor predicted more persistent negative emotion afterward; this effect was attenuated only by prior acute aerobic exercise, in this case, cycling, both 5 min and 15 min poststressor. This effect was unrelated to physical fitness or cognitive performance. Physical fitness level did predict greater attentional control and the capacity to update working memory. Acute aerobic exercise may facilitate subjective emotional recovery from a subsequent stressor and improve emotional flexibility. (PsycINFO Database Record

Resistance Exercise Augments Postprandial Overnight Muscle Protein Synthesis Rates.

We have previously shown that protein ingestion before sleep increases overnight muscle protein synthesis rates. Whether prior exercise further augments the muscle protein synthetic response to presleep protein ingestion remains to be established. This study aimed to assess whether resistance-type exercise performed in the evening increases the overnight muscle protein synthetic response to presleep protein ingestion. Twenty-four healthy young men were randomly assigned to ingest 30 g intrinsically L-[1-C]-phenylalanine and L-[1-C]-leucine-labeled casein protein before going to sleep with (PRO + EX, n = 12) or without (PRO, n = 12) prior resistance-type exercise performed in the evening. Continuous intravenous L-[ring-H5]-phenylalanine, L-[1-C]-leucine, and L-[ring-H2]-tyrosine infusions were applied. Blood and muscle tissue samples were collected to assess whole-body protein balance, myofibrillar protein synthesis rates, and overnight incorporation of dietary protein-derived amino acids into de novo myofibrillar protein. A total of 57% ± 1% of the ingested protein-derived phenylalanine appeared in the circulation during overnight sleep. Overnight myofibrillar protein synthesis rates were 37% (0.055%·h ± 0.002%·h vs. 0.040%·h ± 0.003%·h, P < 0.001, based on L-[ring- H5]-phenylalanine) and 31% (0.073%·h ± 0.004%·h vs. 0.055%·h ± 0.006%·h, P = 0.024, based on L-[1-C]-leucine) higher in PRO + EX compared with PRO. Substantially more of the dietary protein-derived amino acids were incorporated into de novo myofibrillar protein during overnight sleep in PRO + EX compared with PRO (0.026 ± 0.003 vs. 0.015 ± 0.003 molar percent excess, P = 0.012). Resistance-type exercise performed in the evening augments the overnight muscle protein synthetic response to presleep protein ingestion and allows more of the ingested protein-derived amino acids to be used for de novo myofibrillar protein synthesis during overnight sleep.

Timing, Optimal Dose and Intake Duration of Dietary Supplements with Evidence-Based Use in Sports Nutrition.

[Purpose]The aim of the present narrative review was to consider the evidence on the timing, optimal dose and intake duration of the main dietary supplements in sports nutrition, i.e. β-alanine, nitrate, caffeine, creatine, sodium bicarbonate, carbohydrate and protein.[Methods]This review article focuses on timing, optimal dose and intake duration of main dietary supplements in sports nutrition.[Results]This paper reviewed the evidence to determine the optimal time, efficacy doses and intake duration for sports supplements verified by scientific evidence that report a performance enhancing effect in both situation of laboratory and training settings.[Conclusion]Consumption of the supplements are usually suggested into 5 specific times, such as pre-exercise (nitrate, caffeine, sodium bicarbonate, carbohydrate and protein), during exercise (carbohydrate), post-exercise (creatine, carbohydrate, protein), meal time (β-alanine, creatine, sodium bicarbonate, nitrate, carbohydrate and protein), and before sleep (protein). In addition, the recommended dosing protocol for the supplements nitrate and β-alanine are fixed amounts irrespective of body weight, while dosing protocol for sodium bicarbonate, caffeine and creatine supplements are related to corrected body weight (mg/kg bw). Also, intake duration is suggested for creatine and β-alanine, being effective in chronic daily time < 2 weeks while caffeine, sodium bicarbonate are effective in acute daily time (1-3 hours). Plus, ingestion of nitrate supplement is required in both chronic daily time < 28 days and acute daily time (2- 2.5 h) prior exercise.

Effects of Silk Peptides Administration on Fat Utilization Over a Whole Day in Mice.

[Purpose]The aim of the present study was to investigate the effects of treatment with silk peptides (SP) on resting energy expenditure over a 24-h period and clarify the molecular mechanism underlying its enhancement of fat utilization in mouse skeletal muscles.[Methods]Sixteen male ICR mice (6-weekold) were divided into two groups and treated with distilled water and SP (CON and SP treatment groups, respectively). SP were dissolved in distilled water and administered to the SP group at 800 mg/kg while the CON group was administered distilled water orally daily for 2 weeks. Resting metabolic rate (RMR) was measured before and after SP ingestion for 2 weeks using an open circuit calorimetry system. After the treatments, we collected blood and skeletal muscle samples from the mice.[Results]Final body weight and body weight gain showed no significant difference in the CON and SP groups. Conversely, food intake was significantly lower in the SP group than it was in the CON group. The comparison of the respiratory exchange rate (RER) at various time points after the 2-week treatment revealed that it was significantly lower in the SP group than it was in the CON group at 9, 15, 16, and 18-22 h (Figure 3 B). The sum of the RER over 24-h was lower in the SP group than it was in the CON group, but the difference was not statistically significant. The protein levels of fatty acid translocase (FAT)/ cluster of differentiation 36 (CD36) were approximately 12% higher in the SP group than they were in the CON group but that of carnitine palmitoyltransferase I (CPTІ) was not significantly different between the two groups.[Conclusion]These results suggest that treatment with SP 800 mg/kg for 2 weeks may promote fat utilization during physical activity, but not the entire day. In addition, SP treatment effectively enhanced FAT/CD36 protein level in skeletal muscle. In future investigations, it would be necessary to elucidate the effects of long-term SP intake on the resting metabolism of both animals and humans.

Differential response to intrahippocampal interleukin-4/interleukin-13 in aged and exercise mice

Normal aging is associated with low-grade neuroinflammation that results from age-related priming of microglial cells. Further, aging alters the response to several anti-inflammatory factors, including interleukin (IL)-4 and IL-13. One intervention that has been shown to modulate microglia activation in the aged brain, both basally and following an immune challenge, is exercise. However, whether engaging in exercise can improve responsiveness to anti-inflammatory cytokines is presently unknown. The current study evaluated whether prior exercise training increases sensitivity to anti-inflammatory cytokines that promote the M2 (alternative) microglia phenotype in adult (5-month-old) and aged (23-month-old) C57BL/6J mice. After 8weeks of exercise or control housing, mice received bilateral hippocampal injections of an IL-4/IL-13 cocktail or vehicle. Twenty-four hours later hippocampal samples were collected and analyzed for expression of genes associated with the M1 (inflammatory) and M2 microglia phenotypes. Results show that IL-4/IL-13 administration increased expression of the M2-associated genes found in inflammatory zone 1 (Fizz1), chitinase-like 3 (Ym1), Arginase-1 (Arg1), SOCS1, IL-1ra, and CD206. In response to IL-4/IL-13 administration, aged mice showed increased hippocampal expression of the M2-related genes Arg1, SOCS1, Ym1, and CD206 relative to adult mice. Aged mice also showed increased expression of IL-1β relative to adults, which was unaffected by wheel running or IL-4/IL-13. Wheel running was found to have modest effects on expression of Ym1 and Fizz1 in aged and adult mice. Collectively, our findings indicate that aged mice show a differential response to anti-inflammatory cytokines relative to adult mice and that exercise has limited effects on modulating this response.

Pre-Sleep Protein Ingestion to Improve the Skeletal Muscle Adaptive Response to Exercise Training.

Protein ingestion following resistance-type exercise stimulates muscle protein synthesis rates, and enhances the skeletal muscle adaptive response to prolonged resistance-type exercise training. As the adaptive response to a single bout of resistance exercise extends well beyond the first couple of hours of post-exercise recovery, recent studies have begun to investigate the impact of the timing and distribution of protein ingestion during more prolonged recovery periods. Recent work has shown that overnight muscle protein synthesis rates are restricted by the level of amino acid availability. Protein ingested prior to sleep is effectively digested and absorbed, and thereby stimulates muscle protein synthesis rates during overnight recovery. When applied during a prolonged period of resistance-type exercise training, protein supplementation prior to sleep can further augment gains in muscle mass and strength. Recent studies investigating the impact of pre-sleep protein ingestion suggest that at least 40 g of protein is required to display a robust increase in muscle protein synthesis rates throughout overnight sleep. Furthermore, prior exercise allows more of the pre-sleep protein-derived amino acids to be utilized for de novo muscle protein synthesis during sleep. In short, pre-sleep protein ingestion represents an effective dietary strategy to improve overnight muscle protein synthesis, thereby improving the skeletal muscle adaptive response to exercise training.

The repeatability of the abbreviated (4-h) Oral Fat Tolerance Test and influence of prior acute aerobic exercise

PurposeThe Oral Fat Tolerance Test (OFTT) is regarded as a repeatable measure used to assess postprandial triglyceride (TAG) levels, with higher levels observed in cardio-metabolic disorders. Acute aerobic exercise intervention before OFTT reduces the TAG response, but the repeatability of this effect is unknown. The aim of this study was to determine the repeatability of the abbreviated 4-h OFTT with and without immediate prior aerobic exercise.MethodsOn four separate days, healthy adult male participants underwent two 4-h OFTT (n = 10) and another two 4-h OFTT with 1-h of standardised moderate intensity aerobic exercise performed immediately before meal ingestion (n = 11). The OFTT meal composition included 75.4 g total fat, 21.7 g carbohydrate and 13.7 g protein. Venous blood was sampled at baseline and hourly up to 4 h after the OFTT meal ingestion, and TAG area under the curve (AUC) was calculated.ResultsNonparametric Bland–Altman analysis of 4-h TAG AUC revealed that 9 of 10 repeat measurements fell within ±15 % of the median TAG AUC for the OFTT. By contrast, two of 11 repeat measurements fell within ±15 % of the median TAG AUC for the OFTT undertaken with 1-h prior aerobic exercise.ConclusionsThe 4-h OFTT is a repeatable test of postprandial TAG responses in healthy men. However, aerobic exercise performed immediately before OFTT considerably increases the variability of TAG AUC. These findings have implications for interpretation of research studies investigating exercise intervention performed immediately before OFTT. Future studies should also investigate the repeatability of exercise performed 8–24 h before OFTT.

Acute Resistance Exercise Performance Is Negatively Impacted by Prior Aerobic Endurance Exercise.

Ratamess, NA, Kang, J, Porfido, TM, Ismaili, CP, Selamie, SN, Williams, BD, Kuper, JD, Bush, JA, and Faigenbaum, AD. Acute resistance exercise performance is negatively impacted by prior aerobic endurance exercise. J Strength Cond Res 30(10): 2667-2681, 2016-The purpose of the present study was to examine acute resistance exercise (RE) performance after 4 different aerobic endurance (AE) protocols. Eleven healthy, resistance-trained men (21.0 ± 1.2 years) performed a control RE protocol and 4 RE protocols 10 minutes after different AE protocols in random sequence. The RE protocol consisted of 5 exercises (high pull, squat, bench press, deadlift, and push press) performed for 3 sets of 6-10 repetitions with 70-80% of one repetition-maximum (1RM) with 3-minute rest intervals in between sets. The AE protocols consisted of treadmill running at velocities corresponding to: (a) 60% of their V[Combining Dot Above]O2 reserve (V[Combining Dot Above]O2R) for 45 minutes (P1); (b) 75% of their V[Combining Dot Above]O2R for 20 minutes (P2); (c) 90-100% of V[Combining Dot Above]O2R in 3-minute intervals (1:1 ratio) for 5 sets (P3); and (d) 75% of V[Combining Dot Above]O2R (4.5 mph) uphill (6-9% grade) for 20 minutes (P4). Completed repetitions, average power and velocity, heart rate (HR), and ratings of perceived exertion (RPE) were assessed each set. Protocols P1-P4 resulted in 9.1-18.6% fewer total repetitions performed compared with the control RE protocol with the squat experiencing the greatest reduction. Average power and velocity were significantly reduced for the high pull, squat, and bench press after most AE protocols. Ratings of perceived exertion values for the high pull and squat were significantly higher in P1-P4 compared with control. Heart rate was significantly higher during RE after P1-P4 compared with control by 4.3-5.5%. These results indicate acute RE performance is significantly compromised in healthy men after AE exercise of different type, intensity, and duration with largest reductions observed after high-intensity interval exercise.

Prior Exercise Training Prevent Hyperglycemia in STZ Mice by Increasing Hepatic Glycogen and Mitochondrial Function on Skeletal Muscle.

Diabetes mellitus is a metabolic disorder characterized by hyperglycemia. We investigated the effect of a prior 30 days voluntary exercise protocol on STZ-diabetic CF1 mice. Glycemia, and the liver and skeletal muscle glycogen, mitochondrial function, and redox status were analyzed up to 5 days after STZ injection. Animals were engaged in the following groups: Sedentary vehicle (Sed Veh), Sedentary STZ (Sed STZ), Exercise Vehicle (Ex Veh), and Exercise STZ (Ex STZ). Exercise prevented fasting hyperglycemia in the Ex STZ group. In the liver, there was decreased on glycogen level in Sed STZ group but not in EX STZ group. STZ groups showed decreased mitochondrial oxygen consumption compared to vehicle groups, whereas mitochondrial H2 O2 production was not different between groups. Addition of ADP to the medium did not decrease H2 O2 production in Sed STZ mice. Exercise increased GSH level. Sed STZ group increased nitrite levels compared to other groups. In quadriceps muscle, glycogen level was similar between groups. The Sed STZ group displayed decreased O2 consumption, and exercise prevented this reduction. The H2 O2 production was higher in Ex STZ when compared to other groups. Also, GSH level decreased whereas nitrite levels increased in the Sed STZ compared to other groups. The PGC1 α levels increased in Sed STZ, Ex Veh, and Ex STZ groups. In summary, prior exercise training prevents hyperglycemia in STZ-mice diabetic associated with increased liver glycogen storage, and oxygen consumption by the mitochondria of skeletal muscle implying in increased oxidative/biogenesis capacity, and improved redox status of both tissues. J. Cell. Biochem. 118: 678-685, 2017. © 2016 Wiley Periodicals, Inc.

Prior voluntary wheel running attenuates neuropathic pain.

Exercise is known to exert a systemic anti-inflammatory influence, but whether its effects are sufficient to protect against subsequent neuropathic pain is underinvestigated. We report that 6 weeks of voluntary wheel running terminating before chronic constriction injury (CCI) prevented the full development of allodynia for the ∼3-month duration of the injury. Neuroimmune signaling was assessed at 3 and 14 days after CCI. Prior exercise normalized ipsilateral dorsal spinal cord expression of neuroexcitatory interleukin (IL)-1β production and the attendant glutamate transporter GLT-1 decrease, as well as expression of the disinhibitory P2X4R-BDNF axis. The expression of the macrophage marker Iba1 and the chemokine CCL2 (MCP-1), and a neuronal injury marker (activating transcription factor 3), was attenuated by prior running in the ipsilateral lumbar dorsal root ganglia. Prior exercise suppressed macrophage infiltration and/or injury site proliferation, given decreased presence of macrophage markers Iba1, iNOS (M1), and Arg-1 (M2; expression was time dependent). Chronic constriction injury-driven increases in serum proinflammatory chemokines were suppressed by prior running, whereas IL-10 was increased. Peripheral blood mononuclear cells were also stimulated with lipopolysaccharide ex vivo, wherein CCI-induced increases in IL-1β, nitrite, and IL-10 were suppressed by prior exercise. Last, unrestricted voluntary wheel running, beginning either the day of, or 2 weeks after, CCI, progressively reversed neuropathic pain. This study is the first to investigate the behavioral and neuroimmune consequences of regular exercise terminating before nerve injury. This study suggests that chronic pain should be considered a component of "the diseasome of physical inactivity," and that an active lifestyle may prevent neuropathic pain.

The Effect of Prior Exercise on Bone Morphological Microstructure after Immobilization in Mice

PURPOSE The purpose of this study was to analyze the differences of bone density and structure after immobilization prior aerobic exercise and resistance exercise. METHODS Twenty four mice were randomly divided into 3 groups: CC: 4weeks control cage after 2 weeks immobolization (n=7), RT: 4 weeks resistance training after 2 weeks immobilization (n=7), AE: 4 weeks aerobic training after 2 weeks immobilization (n=7). The prior exercise was performed aerobic and resistance exercise. The body weight, muscle weight, and bone morphometric microstructure parameter including bone mineral density (BMD), bone specific surface (BS/BV), percent bone volume (BV/TV), trabecular thickness (Tb/Th), trabecular number (Tb/N), trabecular separation (Tb/Sp), structure model index (SMI), connectivity density, and cross-sectional area was evaluated using by microcomputed tomography (micro-CT). One-way repeated ANOVA was used to evaluate the differences between three groups and paired t-test analysis was applied to examine the different between immobilization leg and non-immobilization leg. RESULTS The results of this study indicated that the body weight was increased after 4 weeks, and decreased after 2 weeks immobilization. The gastronemius and soleus muscle weight was significantly decreased in immobilization leg compared to non-immobilization leg. BMD, BV/TV, BS/BV, Tb/Th, Tb/N, Tb/Sp, and Cross-sectional area in immobilization leg of CC was lower than immobilization leg of RT and AE. CONCLUSIONS These results suggest that 4 weeks prior exercise might improve the bone density and microstructure, even though 2 weeks immobilization. Especially, the prior resistance exercise has more beneficial effects on muscle weight, bone density and microstructure. 색인어: ì‚¬ì „ìš´ë™, ìœ ì‚°ì†Œ, ì €í•­, ê³ ì •, 골미세구조 Keywords: Prior exercise, Aerobic, Resistance, Immobilization, Bone microstructure

Prior Exercise Does Not Reduce Postprandial Lipemia Following a Mixed Glucose Meal When Compared with a Mixed Fructose Meal.

This study examined the effect of prior exercise on postprandial lipemia (PPL) concentration following a mixed meal (MM) made with either glucose or fructose. Sedentary women completed four trials in random order: 1) Rest-Fructose: RF, 2) Rest-Glucose: RG, 3) Exercise-Fructose: EF, 4) Exercise-Glucose: EG. Exercise expended 500 kcal while walking at 70%VO2max. Rest was 60 min of sitting. The morning after each trial, a fasting (12 hr) blood sample was collected followed by consumption of the MM. The MM was blended with whole milk and ice cream plus a glucose or fructose powder. Glucose and fructose powder accounted for 30% of the total kcal within the MM. Blood was collected periodically for 6 hr post-MM and analyzed for PPL. Magnitude of PPL over the 6 hr postmeal was quantified using the triglyceride incremental area under the curve (TG AUCI). Significant differences (p < .05) between trials were determined using repeated-measures ANOVA and Bonferroni post hoc test. There was no significant difference in the TG AUCI between the four trials (p > .05). A significant trial by time interaction for TG concentration was reported (p < .05). Despite lack of change in the AUCI with prior exercise, the lower TG concentration at multiple time points in the EG trial does indicate that prior exercise has some desirable effect on PPL. This study suggests that replacing fructose with glucose sugars and incorporating exercise may minimize PPL following a mixed meal but exercise will need to elicit greater energy expenditure.

No Improved Performance With Repeated-Sprint Training in Hypoxia Versus Normoxia: A Double-Blind and Crossover Study.

Few recent studies indicate that short-term repeated-sprint (RS) training in hypoxia (RSH) improves RS performance compared with identical training under normoxic conditions (RSN) in endurance-trained subjects. To determine the effects of RSH against RSN on RS performance under normoxic and moderate hypoxic conditions, using a randomized, doubleblind, crossover experimental design. Fifteen endurance-trained male subjects (age 25 ± 4 y) performed 4 wk of RS training (3 sessions/wk) in normobaric hypoxia (RSH, FiO2 = 13.8%) and normoxia (RSN, FiO2 = 20.9%) in a crossover manner. Before and after completion of training, RS tests were performed on a cycle ergometer with no prior exercise (RSNE), after an incremental exercise test (RSIE), and after a time-trial test (RSTT) in normoxia and hypoxia. Peak power outputs at the incremental exercise test and time-trial performance were unaltered by RSH in normoxia and hypoxia. RS performance was generally enhanced by RSH, as well as RSN, but there were no additional effects of RSH over RSN on peak and mean sprint power output and the number of repeated sprints performed in the RSNE, RSIE, and RSTT trials under normoxic and hypoxic conditions. The present double-blind crossover study indicates that RSH does not improve RS performance compared with RSN in normoxic and hypoxic conditions in endurance-trained subjects. Therefore, caution should be exercised when proposing RSH as an advantageous method to improve exercise performance.