Effects of postexercise feeding on plasma testosterone, cortisol, and insulin following resistance exercise

The purpose of this study was to examine the effect of postexercise dietary intake on circulating levels of insulin, testosterone, cortisol, and testosterone:cortisol (T:C) after weight training exercise. [This is an excerpt from the abstract. For the complete abstract, please see the document.

The impact of religious fasting on human health

The past two decades have seen a rise in the number of investigations examining the health-related effects of religiously motivated fasts. Islamic Ramadan is a 28 - 30 day fast in which food and drink are prohibited during the daylight hours. The majority of health-specific findings related to Ramadan fasting are mixed. The likely causes for these heterogeneous findings are the differences between studies in the following: 1) the amount of daily fasting time; 2) the percentage of subjects who smoke, take oral medications, and/or receive intravenous fluids; and 3) the subjects' typical food choices and eating habits. Greek Orthodox Christians fast for a total of 180 - 200 days each year, and their main fasting periods are the Nativity Fast (40 days prior to Christmas), Lent (48 days prior to Easter), and the Assumption (15 days in August). The fasting periods are more similar than dissimilar, and they can each be described as a variant of vegetarianism. Some of the more favorable effects of these fasts include the lowering of body mass, total cholesterol, LDL-C, and the LDL-C/HDL-C ratio. The Biblical-based Daniel Fast prohibits the consumption of animal products, refined carbohydrates, food additives, preservatives, sweeteners, flavorings, caffeine, and alcohol. It is most commonly partaken for 21 days, although fasts of 10 and 40 days have been observed. Our initial investigation of the Daniel Fast noted favorable effects on several health-related outcomes, including: blood pressure, blood lipids, insulin sensitivity, and biomarkers of oxidative stress. This review summarizes the health-specific effects of these fasts and provides suggestions for future research

A dual investigation of the effect of dietary supplementation with licorice flavonoid oil on anthropometric and biochemical markers of health and adiposity

<p>Abstract</p> <p>Background</p> <p>Licorice flavonoid oil (LFO) has been reported to minimize visceral adipose tissue gain in obese mice and to result in a decrease in body weight and body fat in humans; the effects of which may be more pronounced when administered in an overfed state.</p> <p>Methods</p> <p>We investigated the effects of LFO in two separate studies. Study 1 included a sample of overweight or grade I-II obese men and women (N = 22) who followed their usual dietary and physical activity programs. Study 2 included a sample of athletic men who followed their usual dietary and physical activity programs but consumed a daily supplemental meal (25% above daily energy requirements) in an attempt to induce a state of overfeeding. In both studies, subjects were randomly assigned (double-blind) to either LFO or a placebo for eight weeks, and anthropometric and multiple biochemical outcomes (e.g., markers of oxidative stress, markers of insulin sensitivity, blood lipids, etc.) were obtained before and following the intervention.</p> <p>Results</p> <p>No differences of statistical significance were noted between LFO and placebo for any measured variable in Study 1 or Study 2. When investigating the percent change from baseline for data in Study 2, although not of statistical significance, subjects in the LFO condition experienced less overall fat gain, as well as attenuation in the elevation in selected blood lipids (e.g., cholesterol, LDL-C, and triglycerides).</p> <p>Conclusion</p> <p>These combined data indicate little effect of LFO supplementation within a sample of overweight/obese men and women or athletic men, with the possible exception of attenuation in body fat gain and selected components of the blood lipid panel in response to an overfeeding condition.</p

Oxidative stress and antioxidant defense mechanisms linked to exercise during cardiopulmonary and metabolic disorders

Oxidative stress has been implicated in the pathophysiology of multiple human diseases, in addition to the aging process. Although various stimuli exist, acute exercise is known to induce a transient increase in reactive oxygen and nitrogen species (RONS), evident by several reports of increased oxidative damage following acute bouts of aerobic and anaerobic exercise. Although the results are somewhat mixed and appear disease dependent, individuals with chronic disease experience an exacerbation in oxidative stress following acute exercise when compared to healthy individuals. However, this increased oxidant stress may serve as a necessary “signal” for the upregulation in antioxidant defenses, thereby providing protection against subsequent exposure to prooxidant environments within susceptible individuals. Here we present studies related to both acute exercise-induced oxidative stress in those with disease, in addition to studies focused on adaptations resulting from increased RONS exposure associated with chronic exercise training in persons with disease

Effect of oral intake of capsaicinoid beadlets on catecholamine secretion and blood markers of lipolysis in healthy adults: a randomized, placebo controlled, double-blind, cross-over study

<p>Abstract</p> <p>Background</p> <p>In the present investigation we compared blood epinephrine (EPI), norepinephrine (NE), free fatty acids (FFA) and glycerol concentrations in response to a capsaicinoid supplement or placebo in healthy adults before and after acute exercise.</p> <p>Methods</p> <p>Twenty subjects ingested a placebo or supplement (Capsimax™, OmniActive Health Technologies; 2 mg capsaicinoids in a microencapsulated matrix) with one week separating conditions. Fasting blood samples were collected during each visit; 30 minutes following a rest period and before placebo or supplement intake (Pre); 2 hours post intake (2 hr); one minute following the cessation of 30 minutes of exercise performed at 65% of maximal heart rate reserve (2.5 hr); 90 minutes following the cessation of exercise (4 hr). Heart rate (HR), systolic (SBP) and diastolic (DBP) blood pressure were recorded at all times.</p> <p>Results</p> <p>A time effect was noted for HR, SBP, and DBP (p < 0.05), with HR and SBP higher at 2.5 hr compared to Pre (due to exercise) and DBP lower at 2.5 hr compared to Pre. No interaction or condition effects were noted for EPI, NE, FFA, or glycerol (p > 0.05). However, a time effect was noted for all variables (p < 0.0001), with values higher than Pre at 2.5 hr for EPI and glycerol, at 2 hr and 2.5 hours for FFA, and at 2 hr, 2.5 hr, and 4 hr for NE (p < 0.05). In terms of percent change from Pre, glycerol was higher with Capsimax™ than for placebo at 4 hr (p = 0.011) and FFA was higher with Capsimax™ than for placebo at 2 hr (p = 0.025) and at 2.5 hr (p = 0.015).</p> <p>Conclusion</p> <p>Ingestion of low dose (2 mg) Capsimax™ was associated with an increase in blood FFA and glycerol at selected times post ingestion, as compared to placebo. However, Capsimax™ had no differing effect on EPI or NE compared to placebo. Lastly, no difference was noted in HR, SBP, or DBP between placebo and Capsimax™.</p

Effect of eicosapentaenoic and docosahexaenoic acid on resting and exercise-induced inflammatory and oxidative stress biomarkers: a randomized, placebo controlled, cross-over study

<p>Abstract</p> <p>Background</p> <p>The purpose of the present investigation was to determine the effects of EPA/DHA supplementation on resting and exercise-induced inflammation and oxidative stress in exercise-trained men. Fourteen men supplemented with 2224 mg EPA+2208 mg DHA and a placebo for 6 weeks in a random order, double blind cross-over design (with an 8 week washout) prior to performing a 60 minute treadmill climb using a weighted pack. Blood was collected pre and post exercise and analyzed for a variety of oxidative stress and inflammatory biomarkers. Blood lactate, muscle soreness, and creatine kinase activity were also measured.</p> <p>Results</p> <p>Treatment with EPA/DHA resulted in a significant increase in blood levels of both EPA (18 ± 2 μmol·L^-1vs. 143 ± 23 μmol·L^-1; p < 0.0001) and DHA (67 ± 4 μmol·L^-1vs. 157 ± 13 μmol·L^-1; p < 0.0001), while no differences were noted for placebo. Resting levels of CRP and TNF-α were lower with EPA/DHA compared to placebo (p < 0.05). Resting oxidative stress markers were not different (p > 0.05). There was a mild increase in oxidative stress in response to exercise (XO and H₂O₂) (p < 0.05). No interaction effects were noted. However, a condition effect was noted for CRP and TNF-α, with lower values with the EPA/DHA condition.</p> <p>Conclusion</p> <p>EPA/DHA supplementation increases blood levels of these fatty acids and results in decreased resting levels of inflammatory biomarkers in exercise-trained men, but does not appear necessary for exercise-induced attenuation in either inflammation or oxidative stress. This may be due to the finding that trained men exhibit a minimal increase in both inflammation and oxidative stress in response to moderate duration (60 minute) aerobic exercise.</p

Prior exercise and antioxidant supplementation: effect on oxidative stress and muscle injury

<p>Abstract</p> <p>Background</p> <p>Both acute bouts of prior exercise (preconditioning) and antioxidant nutrients have been used in an attempt to attenuate muscle injury or oxidative stress in response to resistance exercise. However, most studies have focused on untrained participants rather than on athletes. The purpose of this work was to determine the independent and combined effects of antioxidant supplementation (vitamin C + mixed tocopherols/tocotrienols) and prior eccentric exercise in attenuating markers of skeletal muscle injury and oxidative stress in resistance trained men.</p> <p>Methods</p> <p>Thirty-six men were randomly assigned to: no prior exercise + placebo; no prior exercise + antioxidant; prior exercise + placebo; prior exercise + antioxidant. Markers of muscle/cell injury (muscle performance, muscle soreness, C-reactive protein, and creatine kinase activity), as well as oxidative stress (blood protein carbonyls and peroxides), were measured before and through 48 hours of exercise recovery.</p> <p>Results</p> <p>No group by time interactions were noted for any variable (P > 0.05). Time main effects were noted for creatine kinase activity, muscle soreness, maximal isometric force and peak velocity (P < 0.0001). Protein carbonyls and peroxides were relatively unaffected by exercise.</p> <p>Conclusion</p> <p>There appears to be no independent or combined effect of a prior bout of eccentric exercise or antioxidant supplementation as used here on markers of muscle injury in resistance trained men. Moreover, eccentric exercise as used in the present study results in minimal blood oxidative stress in resistance trained men. Hence, antioxidant supplementation for the purpose of minimizing blood oxidative stress in relation to eccentric exercise appears unnecessary in this population.</p