The effect of aging on the autophagic and heat shock response in human peripheral blood mononuclear cells

Autophagy is a lysosome degradation pathway through which damaged organelles and macromolecules are degraded within the cell. A decrease in activity of the autophagic process has been linked to several age-associated pathologies, including triglyceride accumulation, mitochondrial dysfunction, muscle degeneration, and cardiac malfunction. Here, we examined the differences in the autophagic response using autophagy-inducer rapamycin (Rapa) in peripheral blood mononuclear cells (PBMCs) from young (21.8 ± 1.9 years) and old (64.0 ± 3.7 years) individuals. Furthermore, we tested the interplay between the heat shock response and autophagy systems. Our results showed a significant increase in LC3-II protein expression in response to Rapa treatment in young but not in old individuals. This was associated with a decreased response in MAP1LC3B mRNA levels, but not SQSTM1/p62. Furthermore, HSPA1A mRNA was upregulated only in young individuals, despite no differences in HSP70 protein expression. The combined findings suggest a suppressed autophagic response following Rapa treatment in older individuals

THE EFFECT OF ACUTE CREATINE MONOHYDRATE LOADING ON BODY COMPOSITION, STRENGTH, AND FATIGABILITY IN WOMEN

Michaela Grace Alesi1, Benjamin E. Dalton2, Jacob M. McDougle3, Ginger Nee4, Darren G. Candow5, Abbie E. Smith-Ryan6, Robert Buresh4, Garrett M. Hester4, Trisha A. VanDusseldorp4. 1Virginia Polytechnic Institute and State University, Blacksburg, VA. 2University of Guelph, Guelph, ON. 3University of Conneticut, Storrs, CT. 4Kennesaw State University, Kennesaw, GA. 5University of Regina, Regina, SK. 6University of North Carolina, Chapel Hill, NC. BACKGROUND: Creatine monohydrate is a well-researched supplement; however, few investigations have been conducted on its effect on women, and only one study to date has factored in the phases of the menstrual cycle. Acute supplementation with creatine monohydrate during exercise has been promoted to benefit body composition and increases in strength and fatigue resistance, however, these findings are more ambiguous in women as much of the data exists from investigations of men. METHODS: Twelve recreationally trained women (22.8 ± 2.98 yrs) participated in this cross-over study, wherein they took both supplements (creatine monohydrate, CM; placebo, maltodextrin, PL) in randomized, double-blind, counterbalance order during the luteal phase of their menstrual cycle. Women were asked to perform a CM or PL loading phase of 20g per day. A 28-day washout period was allowed after the initial supplementation period. Subjects completed 5 total visits. Visit 1 included informed consent and familiarization with the fatiguing exercise protocol. Visits 2-5 comprised measures of 4-compartment body composition and fatiguing exercise on an isokinetic dynamometer. The fatiguing protocol consisted of isokinetic knee extensions at 180 deg/sec for 5 sets of 30 contractions, with 2 min of rest after each set. After each set, participants were asked their rating of perceived exertion using the Borg 1-10 scale. Fatigue index was calculated as followed: (highest peak torque-minimum peak torque)/highest peak torque × 100. Relative fatigue was calculated for each set as follows: (sum of peak toques for set 1 - sum of peak torque for set 2)/sum of peak torques for set 1 × 100. RESULTS: No significant changes for body mass (p=0.551), total body water (p=0.607), fat-free mass (p=0.789), or fat mass (p=0.943) were measured. Strength was unchanged, with no significant changes for peak torque (p=0.646). There was no change in relative fatigue (p= 0.525; p=0.525) or fatigue index (p= 0.823; p=0.149). There was no difference for rating of perceived exertion (p=0.570). CONCLUSIONS: A creatine monohydrate loading period of 20 grams per day for five days did not alter body composition, muscular strength, or fatigability in these recreationally trained women

International society of sports nutrition position stand: caffeine and exercise performance

Following critical evaluation of the available literature to date, The International Society of Sports Nutrition (ISSN) position regarding caffeine intake is as follows:1.Supplementation with caffeine has been shown to acutely enhance various aspects of exercise performance in many but not all studies. Small to moderate benefits of caffeine use include, but are not limited to: muscular endurance, movement velocity and muscular strength, sprinting, jumping, and throwing performance, as well as a wide range of aerobic and anaerobic sport-specific actions.2.Aerobic endurance appears to be the form of exercise with the most consistent moderate-to-large benefits from caffeine use, although the magnitude of its effects differs between individuals.3.Caffeine has consistently been shown to improve exercise performance when consumed in doses of 3–6 mg/kg body mass. Minimal effective doses of caffeine currently remain unclear but they may be as low as 2 mg/kg body mass. Very high doses of caffeine (e.g. 9 mg/kg) are associated with a high incidence of side-effects and do not seem to be required to elicit an ergogenic effect.4.The most commonly used timing of caffeine supplementation is 60 min pre-exercise. Optimal timing of caffeine ingestion likely depends on the source of caffeine. For example, as compared to caffeine capsules, caffeine chewing gums may require a shorter waiting time from consumption to the start of the exercise session.5.Caffeine appears to improve physical performance in both trained and untrained individuals.6.Inter-individual differences in sport and exercise performance as well as adverse effects on sleep or feelings of anxiety following caffeine ingestion may be attributed to genetic variation associated with caffeine metabolism, and physical and psychological response. Other factors such as habitual caffeine intake also may play a role in between-individual response variation.7.Caffeine has been shown to be ergogenic for cognitive function, including attention and vigilance, in most individuals.8.Caffeine may improve cognitive and physical performance in some individuals under conditions of sleep deprivation.9.The use of caffeine in conjunction with endurance exercise in the heat and at altitude is well supported when dosages range from 3 to 6 mg/kg and 4–6 mg/kg, respectively.10.Alternative sources of caffeine such as caffeinated chewing gum, mouth rinses, energy gels and chews have been shown to improve performance, primarily in aerobic exercise.11.Energy drinks and pre-workout supplements containing caffeine have been demonstrated to enhance both anaerobic and aerobic performance