The Impact of Intensity on Exercise-Induced Oxidative Stress in Trained Men

Exercise has been noted in some, but not all studies, to elicit an oxidative stress response. The discrepancy in findings may be related to differences in exercise intensity across study protocols. Biomarkers of oxidative stress were compared for aerobic and anaerobic exercise bouts of different intensities and durations. On different days, exercised-trained men (n=12; 21-35 yrs) performed aerobic cycle exercise (60 min at 70% HR reserve) and anaerobic cycle sprints (five, 60 sec sprints at 100% max GXT watts; and ten, 15 sec sprints at 200% max GXT watts). Blood was collected before and 0, 30, and 60 min post-exercise and analyzed for malondialdehyde (MDA), hydrogen peroxide (H2O2), and Trolox Equivalent Antioxidant Capacity (TEAC). No differences were noted in MDA or H2O2. TEAC was significantly higher at 30 and 60 min post-exercise. In exercise-trained men, no increase was noted in post-exercise oxidative stress, possibly due to the increase in antioxidant defense

Relationship Between Metabolic By-Products and Nervous System Failure/Fatigue

Fatigue has generally been defined as an acute impairment of exercise/sport performance that includes both an increase in the perceived effort necessary to exert a desired force or power output, and the inability to produce the desired force or power output. The majority of research to date looking at fatigue has focused upon substrate utilization, however, what is relatively unknown is the contribution the nervous system has upon fatigue. Therefore, the purpose of this dissertation was to investigate potential mechanisms that relate to neural fatigue. An additional purpose was to determine if there were any relationships between metabolic by-products and EMG characteristics following exercise. The first investigation sought to determine changes in EMG M-wave amplitude of the gastrocnemius following the calf raise exercise. There were no significant changes in M-wave EMG amplitude following exercise. The second investigation compared changes in muscle contractile properties and EMG characteristics of the VL, RF, and VM following a high-intensity exercise. There was a significant decrease in MDF of the VL only. Additionally, there was a decrease in peak force and rate of force development. The last investigation utilized the same exercise protocol as the second investigation, but added the supplementation of aspartate and sodium bicarbonate. Both supplements were effective in reducing ammonia concentrations following exercise. Additionally, supplementation with sodium bicarbonate resulted in an increase in rate of force development following exercise. As for EMG characteristics, there was a significant decrease in MDF for the RF, but not the VL. There were no significant changes in PF or EMG amplitude. Currently, no relationship between the metabolic and nervous systems during times of fatigue can be determined at this point

Impact of a Dietary Supplement Containing 1,3-Dimethylamylamine on Blood Pressure and Bloodborne Markers of Health: a 10-Week Intervention Study

Background 1,3-dimethylamylamine is a commonly used ingredient within dietary supplements. Our prior work with this agent indicates a transient increase in blood pressure (systolic in particular) following oral ingestion of a single dosage, but no significant increase in resting blood pressure following chronic ingestion. Moreover, intervention studies involving both two and eight weeks of treatment with finished products containing 1,3-dimethylamylamine indicate minimal or no change in bloodborne markers of health. The present study sought to extend these findings by using a 10 -week intervention trial to determine the change in selected markers of health in a sample of men. Methods 25 healthy men were randomly assigned to either a placebo (n = 13) or to a supplement containing 1,3-dimethylamylamine (n = 12) for a period of 10 weeks. Before and after the intervention, resting blood pressure and heart rate were measured, and blood samples were collected for determination of complete blood count, metabolic panel, and lipid panel. Results No significant differences were noted between conditions for blood pressure ( P > 0.05), although systolic blood pressure increased approximately 6 mmHg with the supplement (diastolic blood pressure decreased approximately 4 mmHg). A main effect for time was noted for heart rate ( P = 0.016), with values decreasing from pre to post intervention. There were significant main effects for time for creatinine (increased from pre to post intervention; P = 0.043) and alkaline phosphatase (decreased from pre to post intervention; P = 0.009), with no condition differences noted ( P > 0.05). There was a significant interaction noted for low density lipoprotein cholesterol (LDL-C) ( P = 0.043), with values decreasing in the supplement group from pre to post intervention approximately 7 mg · dL -1 ( P = 0.034). No other effects of significance were noted for bloodborne variables. Conclusion These data indicate that a dietary supplement containing 1,3-dimethylamylamine does not result in a statistically significant increase in resting heart rate or blood pressure (although systolic blood pressure is increased ~6 mmHg with supplement use). The supplement does not negatively impact bloodborne markers of health. Further study is needed involving a longer intervention period, a larger sample size, and additional measures of health and safety

A Comparison of an Aerobic Exercise Program and a Resistance Training Program on Cognitive Functioning in Healthy College Students

Cognitive functioning declines begin occurring as early as 30 years of age. Research has found evidence that exercise influences cognitive functioning in elderly patients with Alzheimer\u27s and dementia. However, while cognitive functioning has often been linked to academic achievement, there is a lack of research examining exercise and cognitive functioning in young and healthy populations. Furthermore, research has found both aerobic and resistance training can impact cognitive functioning, but there is a lack of literature comparing the impact of exercise mode on cognitive functioning. PURPOSE: To explore the differences between an aerobic and resistance training program on cognitive functioning in healthy college students. METHODS: A total of 15 students (n = 6 M, n = 9 F) participated in this study. Participants completed a demographic questionnaire and the Stroop Effect Test with two congruent tables and one incongruent. Participants were then randomly assigned to either an aerobic or resistance training program. Participants assigned to the aerobic program cycled for 30 minutes at 60-70% of their age-predicted maximal heart rate. Participants in the resistance program completed a machine-based protocol consisting of ten strength exercises at 70% of their theoretical 1RM. These participants performed three sets of 12 repetitions in any order with 30-60 seconds of rest between exercises. All participants completed their assigned exercise protocol three times a week for four weeks. At the end of the exercise protocol, the participants completed the Stroop Effect Test a second time. An independent-samples t-test was calculated to compare mean Stroop Effect Test scores for participants in both training groups. A paired-samples t-test was conducted to compare Stroop Effect Test pre-test and post-test scores for all participants. RESULTS: No significant difference was found (t(13) = .699, p = .497 g = .362) between Stroop Effect Test scores of the aerobic training group (M = 4.75, SD = 9.33) and the resistance training group (M = 7.71, SD = 6.63). A significant increase in Stroop Effect Test scores from pre-test (M = 43.80, SD = 8.44) to post-test (M = 49.93, SD = 10.23) was found (t(14) = -2.95, p = .01, d = .654) for participants, regardless of exercise protocol. CONCLUSION: No significant difference in Stroop Effect Test scores between the aerobic and resistance group suggests that there is no difference between type of exercise and cognitive improvements in healthy college students. Results showed a significant improvement from the Stroop Effect Test pre-test and post-test scores for participants in both exercise groups, providing further evidence that exercise can improve cognitive function, regardless of exercise mode

Hand Cooling during Recovery from Exercise in the Heat: Cold Water Immersion vs. Dry Cold Negative Pressure

Areas of the body that are devoid of hair, such as the palms of our hands, efficiently dissipate heat through specialized blood vessels. Immersing the hands in cold water is said to benefit the process of heat exchange, but has been criticized for its ability induce cutaneous vasoconstriction. The use of dry cold negative pressure is proposed to bypass this reflex in order to increase constant heat dissipation. PURPOSE: To compare the effect of two different hand cooling modalities on core temperature when recovering from exercise in a hot environment. METHODS: Males (N=12, 21±2 yr, 64±15 kg, 174±6 cm) of average cardiorespiratory fitness (VO2Peak=37+3 ml.kg-1.min-1) participated in three heat trials (35.1±0.2°C, 42±1%RH,) where they exercised on a cycle ergometer at 65% VO2Peak until a desired core temperature (38.3°C), 95% of heart rate max, or until volitional maximum. During recovery from the heat trials, subjects underwent one of three hand cooling treatments for 10 min [cold water immersion (WTR), dry cold negative pressure (NEG), and a control with no hand cooling (CON)] in a balanced crossover design. In WTR trials subjects submerged one hand in cold (10°C) water, and in NEG the hand was placed in sealed cold (10°C) container (AVAcore CoreControl Pro) that provided negative pressure (-47 mm Hg). Heart rate (HR) and core temperature (rectal, Tre) were measured pre-/post-recovery cooling. Two way (cooling method x time) repeated measures ANOVA was used to analyze recovery HR and Tre (α=0.05). RESULTS: The main effect for cooling method was not significant for both HR (WTR=117±12 bpm, NEG=113±9 bpm, CON=118±13 bpm)(p=0.1650) and Tre (WTR=37.7±0.3°C, NEG=37.8±0.2°C, CON=37.8±0.3°C)(p=0.3560) during recovery. As expected, the main effect for time was significant for both Tre (Pre=37.8±0.2°C, Post=37.6±0.2°C)(p=0.0040) and HR (Pre=135±13 bpm, Post=97±9 bpm)(p=0.0001) as both declined during recovery. The cooling method x time interaction (p=0.4280) did not demonstrate that Tre decreased differently between the three cooling modalities, but the cooling method x time interaction for HR was significant (p=0.0320) where the change in HR during recovery periods did differ significantly between the cooling modalities. The significant interaction was driven by the WTR treatment HR declining at a slightly quicker rate than NEG and CON. CONCLUSION: The use of WTR or NEG didn’t decrease Tre any more efficiently than CON, but recovery HR did decline at slightly greater rate in WTR compared to both NEG and CON. This could suggest that while WTR provided a similar Tre reduction as NEG and CON, it did so with a quicker reduction in heart work

Acute vs. Chronic Citrulline Malate Supplementation on Muscle Fatigue

Citrulline malate has been proposed to aid in reducing fatigue by increasing blood flow through promoting an increase in the nitric oxide synthase pathway along with the ability to remove ammonia and lactate accumulations. Results on the effectiveness of an acute supplementation are mixed, but it is proposed that regular consumption may help to attenuate the onset of fatigue during exercise. PURPOSE: To investigate the effects of acute and chronic citrulline malate supplementation on fatigue rate of the quadriceps. METHODS: Recreationally trained males (n=18, 24±5 yr, 83±14 kg, 174±6 cm) participated in seven testing sessions. The familiarization session consisted of participants performing a graded exercise test to determine max power output. In a randomized, counterbalanced order, participants consumed a placebo (PL) and citrulline malate (CM) treatment for two separate dosing periods. For each dosing period, participants reported on three separate days with seven days between each visit. The first experimental testing session for each dosing period was considered the baseline day (BL), the second session the acute day (D1), and the third session the chronic day (D2). For chronic supplementation, all participants consumed each treatment for seven consecutive days. The exercise protocol all testing sessions and the four supplemental testing sessions included exercising on a cycle ergometer at 50-60% of their max power output for 30 min. Following the bout, all participants performed the Thorstensson test on an isokinetic dynamometer for torque, power, and fatigue rate of the dominate leg quadriceps. RESULTS: The acute supplement x time interactions were not significant (p\u3e0.05) for peak power (PL BL 469+81 W, PL D1 490+97 W vs. CM BL 465+85 W, CM D1 480+103 W), peak torque (PL BL 150+26 Nm, PL D1 157+32 Nm vs. CM BL 149+26 Nm, CM D1 156+33 Nm), fatigue rate (PL BL 57+9%, PL D1 57+10% vs. CM BL 57+10%, CM D1 56+9%), and heart rate (PL BL 156+17 bpm, PL D1 146+13 bpm vs. CM BL 155+11 bpm, CM D1 146+11 bpm). The chronic supplement x time interactions were not significant (p\u3e0.05) for peak power (PL BL 469+81 W, PL D2 501+99 W vs. CM BL 464+85 W, CM D2 501+81 W), peak torque (PL BL 150+26 Nm, PL D2 161+31 Nm vs. CM BL 149+27 Nm, CM D2 161+26 Nm), fatigue rate (PL BL 57+9%, PL D2 58+9% vs. CM BL 57+10%, CM D2 58+9%), and heart rate (PL BL 156+17 bpm, PL D2 146+9 bpm vs. CM BL 155+11 bpm, CM D2 146+9 bpm). CONCLUSION: The results of this study suggest that neither acute or chronic supplementation of CM had an effect on recovery or fatigue rate of the quadriceps. Based on the data collected there were no significant differences between the recorded values for torque and power for each participant

A Pre-Exercise Dose of Melatonin Can Alter Substrate Use During Exercise

International Journal of Exercise Science 10(7): 1029-1037, 2017. Notwithstanding the lack of exercise research, several reviews have championed the use of melatonin to combat metabolic syndrome. Therefore, this study compared substrate utilization during a 30-minute (min) graded exercise protocol following the ingestion of either 6 mg melatonin (M) or a placebo (P). Participants (12 women, 12 men) performed stages 1-5 of the Naughton graded exercise protocol (6 min per stage). The protocol was repeated 4 times (2x M, 2x P) at the same time of day with one week separating each session. Expired gases were monitored, VO2 and respiratory exchange ratio (RER) output was provided every 30s. Total, carbohydrate (CHO), and fat energy expenditures were obtained from the RER values using the formulae of Lusk. The VO2 at which CHO accounted for 50% of the total caloric expenditure was calculated by a VO2: RER regression line. Additionally, the energy derived was calculated by multiplying VO2 and the respective energy expenditures. Then, the total, CHO, and fat energies consumed during the 30 min of exercise were determined by calculating the area under the kJ/min: time curve using the trapezoid rule. The final data for the two similar trials were averaged and a paired-T test was used for statistical comparison. The average VO2 for 50% CHO usage was significantly lower following M (0.84 ± 0.54 l·min-1) than after P (1.21 ± 0.52 l·min-1). Also, average CHO kJ for M (627 ± 284) was significantly (p \u3c 0.004) greater than P (504 ± 228), and accounted for a significantly greater contribution of total kJ consumed (M = 68% ±15 vs. P = 61% ± 18). Ingestion of melatonin 30 min prior to an aerobic exercise bout elevates CHO use during exercise

A 21 day Daniel Fast improves selected biomarkers of antioxidant status and oxidative stress in men and women

<p>Abstract</p> <p>Background</p> <p>Dietary modification via both caloric and nutrient restriction is associated with multiple health benefits, some of which are related to an improvement in antioxidant status and a decrease in the production of reactive oxygen species. The Daniel Fast is based on the Biblical book of Daniel, is commonly partaken for 21 days, and involves food intake in accordance with a stringent vegan diet. The purpose of the present study was to determine the effect of a 21 day Daniel Fast on biomarkers of antioxidant status and oxidative stress.</p> <p>Methods</p> <p>43 subjects (13 men; 30 women; 35 ± 1 yrs; range: 20-62 yrs) completed a 21 day Daniel Fast following the guidelines provided by investigators. Subjects reported to the lab in a 12 hour post-absorptive state both pre fast (day 1) and post fast (day 22). At each visit, blood was collected for determination of malondialdehyde (MDA), hydrogen peroxide (H₂O₂), nitrate/nitrite (NOx), Trolox Equivalent Antioxidant Capacity (TEAC), and Oxygen Radical Absorbance Capacity (ORAC). Subjects recorded dietary intake during the 7 day period immediately prior to the fast and during the final 7 days of the fast.</p> <p>Results</p> <p>A decrease was noted in MDA (0.66 ± 0.0.03 vs. 0.56 ± 0.02 μmol L^-1; p = 0.004), while H₂O₂demonstrated a trend for lowering (4.42 ± 0.32 vs. 3.78 ± 0.21 μmol L^-1; p = 0.074). Both NOx (18.79 ± 1.92 vs. 26.97 ± 2.40 μmol L^-1; p = 0.003) and TEAC (0.47 ± 0.01 vs. 0.51 ± 0.01 mmol L^-1; p = 0.001) increased from pre to post fast, while ORAC was unchanged (5243 ± 103 vs. 5249 ± 183 μmol L^-1TE; p = 0.974). As expected, multiple differences in dietary intake were noted (p < 0.05), including a reduction in total calorie intake (2185 ± 94 vs. 1722 ± 85).</p> <p>Conclusion</p> <p>Modification of dietary intake in accordance with the Daniel Fast is associated with an improvement in selected biomarkers of antioxidant status and oxidative stress, including metabolites of nitric oxide (i.e., NOx).</p

Effect of a 21 day Daniel Fast on metabolic and cardiovascular disease risk factors in men and women

<p>Abstract</p> <p>Background</p> <p>Dietary modification via caloric restriction is associated with multiple effects related to improved metabolic and cardiovascular health. However, a mandated reduction in kilocalories is not well-tolerated by many individuals, limiting the long-term application of such a plan. The Daniel Fast is a widely utilized fast based on the Biblical book of Daniel. It involves a 21 day <it>ad libitum </it>food intake period, devoid of animal products and preservatives, and inclusive of fruits, vegetables, whole grains, legumes, nuts, and seeds. The purpose of the present study was to determine the efficacy of the Daniel Fast to improve markers of metabolic and cardiovascular disease risk.</p> <p>Methods</p> <p>43 subjects (13 men; 30 women; 35 ± 1 yrs; range: 20-62 yrs) completed a 21 day period of modified food intake in accordance with detailed guidelines provided by investigators. All subjects purchased and prepared their own food. Following initial screening, subjects were given one week to prepare for the fast, after which time they reported to the lab for their pre-intervention assessment (day 1). After the 21 day fast, subjects reported to the lab for their post-intervention assessment (day 22). For both visits, subjects reported in a 12 hr fasted state, performing no strenuous physical activity during the preceding 24-48 hrs. At each visit, mental and physical health (SF-12 form), resting heart rate and blood pressure, and anthropometric variables were measured. Blood was collected for determination of complete blood count, metabolic panel, lipid panel, insulin, HOMA-IR, and C-reactive protein (CRP). Subjects' self-reported compliance, mood, and satiety in relation to the fast were also recorded. Diet records were maintained by all subjects during the 7 day period immediately prior to the fast (usual intake) and during the final 7 days of the fast.</p> <p>Results</p> <p>Subjects' compliance to the fast was 98.7 ± 0.2% (mean ± SEM). Using a 10 point scale, subjects' mood and satiety were both 7.9 ± 0.2. The following variables were significantly (p < 0.05) lower following the fast as compared to before the fast: white blood cell count (5.68 ± 0.24 vs. 4.99 ± 0.19 10³·μL^-1), blood urea nitrogen (13.07 ± 0.58 vs. 10.14 ± 0.59 mg·dL^-1), blood urea nitrogen/creatinine (14.74 ± 0.59 vs. 11.67 ± 0.68), protein (6.95 ± 0.07 vs. 6.77 ± 0.06 g·dL^-1), total cholesterol (171.07 ± 4.57 vs. 138.69 ± 4.39 mg·dL^-1), LDL-C (98.38 ± 3.89 vs. 76.07 ± 3.53 mg·dL^-1), HDL-C (55.65 ± 2.50 vs. 47.58 ± 2.19 mg·dL^-1), SBP (114.65 ± 2.34 vs. 105.93 ± 2.12 mmHg), and DBP (72.23 ± 1.59 vs. 67.00 ± 1.43 mmHg). Insulin (4.42 ± 0.52 vs. 3.37 ± 0.35 μU·mL^-1; p = 0.10), HOMA-IR (0.97 ± 0.13 vs.0.72 ± 0.08; p = 0.10), and CRP (3.15 ± 0.91 vs. 1.60 ± 0.42 mg·L^-1; p = 0.13), were lowered to a clinically meaningful, albeit statistically insignificant extent. No significant difference was noted for any anthropometric variable (p > 0.05). As expected, multiple differences in dietary intake were noted (p < 0.05), including a reduction in total kilocalorie intake (2185 ± 94 vs. 1722 ± 85).</p> <p>Conclusion</p> <p>A 21 day period of modified dietary intake in accordance with the Daniel Fast is 1) well-tolerated by men and women and 2) improves several risk factors for metabolic and cardiovascular disease. Larger scale, randomized studies, inclusive of a longer time period and possibly a slight modification in food choice in an attempt to maintain HDL cholesterol, are needed to extend these findings.</p