0
selected
-
1.
Protein intake during training sessions has no effect on performance and recovery during a strenuous training camp for elite cyclists.
Hansen, M, Bangsbo, J, Jensen, J, Krause-Jensen, M, Bibby, BM, Sollie, O, Hall, UA, Madsen, K
Journal of the International Society of Sports Nutrition. 2016;:9
Abstract
BACKGROUND Training camps for top-class endurance athletes place high physiological demands on the body. Focus on optimizing recovery between training sessions is necessary to minimize the risk of injuries and improve adaptations to the training stimuli. Carbohydrate supplementation during sessions is generally accepted as being beneficial to aid performance and recovery, whereas the effect of protein supplementation and timing is less well understood. We studied the effects of protein ingestion during training sessions on performance and recovery of elite cyclists during a strenuous training camp. METHODS In a randomized, double-blinded study, 18 elite cyclists consumed either a whey protein hydrolysate-carbohydrate beverage (PRO-CHO, 14 g protein/h and 69 g CHO/h) or an isocaloric carbohydrate beverage (CHO, 84 g/h) during each training session for six days (25-29 h cycling in total). Diet and training were standardized and supervised. The diet was energy balanced and contained 1.7 g protein/kg/day. A 10-s peak power test and a 5-min all-out performance test were conducted before and after the first training session and repeated at day 6 of the camp. Blood and saliva samples were collected in the morning after overnight fasting during the week and analyzed for biochemical markers of muscle damage, stress, and immune function. RESULTS In both groups, 5-min all-out performance was reduced after the first training session and at day 6 compared to before the first training session, with no difference between groups. Peak power in the sprint test did not change significantly between tests or between groups. In addition, changes in markers for muscle damage, stress, and immune function were not significantly influenced by treatment. CONCLUSIONS Intake of protein combined with carbohydrate during cycling at a training camp for top cyclists did not result in marked performance benefits compared to intake of carbohydrates when a recovery drink containing adequate protein and carbohydrate was ingested immediately after each training session in both groups. These findings suggest that the addition of protein to a carbohydrate supplement consumed during exercise does not improve recovery or performance in elite cyclists despite high demands of daily exhaustive sessions during a one-week training camp.
-
2.
The role of vitamin D in health preservation and exertional capacity of athletes.
Stachowicz, M, Lebiedzińska, A
Postepy higieny i medycyny doswiadczalnej (Online). 2016;(0):637-43
Abstract
Sports training causes an increased load on the musculoskeletal, hormonal and immune system, which makes maintaining homeostasis in the organism more difficult. Maintaining metabolic balance in the athlete's body is important due to the necessity to obtain high physical fitness. One factor that facilitates optimization of health and increased endurance is a balanced diet. Proper nutrition enables provision of energy-giving and body-building substances as well as bioelements and vitamins, which influence metabolic processes and play regulatory functions. Vitamin D, also called calciferol, has an impact on maintaining effectiveness of the musculoskeletal system, on mineralization of bones and on increase of mass, strength and endurance of muscles. An association between vitamin D content in the organism and levels of anabolic hormones such as insulin and testosterone has been reported. A sufficient amount of calciferol is also necessary for effective functioning of the nervous system, including keeping balance and determining the reaction time. Maintaining an adequate vitamin D level in the athlete's body is also important due to its role in mobilizing the immune system and preventing infections, to which athletes are particularly prone. The positive impact of vitamin D on physical fitness of athletes shows how important it is to maintain its adequate level in the organism. Numerous studies indicate widespread occurrence of vitamin D deficiency, including among athletes. Climatic conditions and training in halls lead to limited endogenous production of this vitamin, which shows the importance of diet as a source of vitamin D. The aim of the study is to present the role of vitamin D in preservation of health, particularly endurance and physical fitness of athletes, on the basis of currently available scientific literature.
-
3.
[Effects of branched amino acids in endurance sports: a review].
Salinas-García, ME, Martínez-Sanz, JM, Urdampilleta, A, Mielgo-Ayuso, J, Norte Navarro, A, Ortiz-Moncada, R
Nutricion hospitalaria. 2014;(2):577-89
Abstract
INTRODUCTION The report issued by the European Food Safety Agency (EFSA) in 2010 on nutrition and health claims, shows that there is no scientific evidence to support supplementation with branched chain amino acids (BCAAs). The aim of this study is to analyze the effects of consumption of BCAAs in endurance sports. METHODS A literature review on the current state of the effect of consumption of dietary supplements of BCAAs. We conducted a search in the PubMed database and snowball strategy. INCLUSION CRITERIA Spanish / English randomized clinical trial related to the consumption of BCAAs, leucine, valine and isoleucine in endurance sports and its effects on muscle damage, athletic performance, central fatigue, anabolic signals during recovery and immune system response published in any country until May 2014. RESULTS Out of 330 studies identified, 14 met the inclusion criteria. The mean of subjects participating in the study was (11.36±7.43). Only two studies included a group of women. The sports that we found in the studies were: run, cycling, combining cycling and running, Olympic distance triathlon and one study included 2 groups of athletes (Olympic distance triathletes and runners). The effects of BCAAs and muscle damage, athletic performance, central fatigue, anabolic signals during recovery period and immune response were studied at different times: before, during and after training or a combination of these. DISCUSSION It is observed that there is a lesser degree of pain and muscle damage, less perceived exertion and mental fatigue, greater anabolic response in recovery period and improved immune response when supplemented with BCAAs, notwithstanding its decision before or during physical activity does not improve athletic performance. No consensus was found in the dose and timing of the most effective decision, although it is more effective if there is 2-3/1/1g relationship between leucine / isoleucine and valine amino acids.
-
4.
Exercise-induced immunodepression in endurance athletes and nutritional intervention with carbohydrate, protein and fat-what is possible, what is not?
Gunzer, W, Konrad, M, Pail, E
Nutrients. 2012;(9):1187-1212
Abstract
Heavily exercising endurance athletes experience extreme physiologic stress, which is associated with temporary immunodepression and higher risk of infection, particularly upper respiratory tract infections (URTI). The aim of this review is to provide a critical up-to-date review of existing evidence on the immunomodulatory potential of selected macronutrients and to evaluate their efficacy. The results of 66 placebo-controlled and/or crossover trials were compared and analysed. Among macronutrients, the most effective approach to maintain immune function in athletes is to consume ≥6% carbohydrate during prolonged exercise. Because inadequate nutrition affects almost all aspects of the immune system, a well-balanced diet is also important. Evidence of beneficial effects from other macronutrients is scarce and results are often inconsistent. Using a single nutrient may not be as effective as a mixture of several nutritional supplements. Due to limited research evidence, with the exception of carbohydrate, no explicit recommendations to reduce post-exercise URTI symptoms with single macronutrients can be derived.
-
5.
Cognitive awareness of carbohydrate intake does not alter exercise-induced lymphocyte apoptosis.
Navalta, JW, McFarlin, BK, Lyons, S, Arnett, SW, Schafer, MA
Clinics (Sao Paulo, Brazil). 2011;(2):197-202
Abstract
OBJECTIVE The purpose of this investigation was to determine whether cognitive awareness of carbohydrate beverage consumption affects exercise-induced lymphocyte apoptosis, independent of actual carbohydrate intake. INTRODUCTION Carbohydrate supplementation during aerobic exercise generally protects against the immunosuppressive effects of exercise. It is not currently known whether carbohydrate consumption or simply the knowledge of carbohydrate consumption also has that effect. METHODS Endurance trained male and female (N = 10) athletes were randomly assigned to one of two groups based on either a correct or incorrect cognitive awareness of carbohydrate intake. In the incorrect group, the subjects were informed that they were receiving the carbohydrate beverage but actually received the placebo beverage. Participants completed a 60-min ride on a cycle ergometer at 80% VO₂peak under carbohydrate and placebo supplemented conditions. Venous blood samples were collected at rest and immediately after exercise and were used to determine the plasma glucose concentration, lymphocyte count, and extent of lymphocyte apoptosis. Cognitive awareness, either correct or incorrect, did not have an effect on any of the measured variables. RESULTS Carbohydrate supplementation during exercise did not have an effect on lymphocyte count or apoptotic index. Independent of drink type, exercise resulted in significant lymphocytosis and lymphocyte apoptosis (apoptotic index at rest = 6.3 ± 3% and apoptotic index following exercise = 11.6 ± 3%, P < 0.01). CONCLUSION Neither carbohydrate nor placebo supplementation altered the typical lymphocyte apoptotic response following exercise. While carbohydrate supplementation generally has an immune-boosting effect during exercise, it appears that this influence does not extend to the mechanisms that govern exercise-induced lymphocyte cell death.
-
6.
Carbohydrate intake during endurance exercise increases natural killer cell responsiveness to IL-2.
McFarlin, BK, Flynn, MG, Stewart, LK, Timmerman, KL
Journal of applied physiology (Bethesda, Md. : 1985). 2004;(1):271-5
Abstract
The purpose of this study was to evaluate the effect of high-intensity endurance exercise and carbohydrate consumption on in vitro responsiveness of natural killer (NK) to IL-2 (2.5 U/ml for 24 h). Thirteen male subjects (18-26 yr old; peak O2 consumption = 59.79 +/- 5.13 ml.kg-1.ml-1) were recruited to complete two 1-h (75-80% peak O2 consumption) cycling trials in a random counterbalanced order: carbohydrate (CHO) and placebo (Pla). Venous blood samples were collected before (Pre), immediately (Post), 2 h (2H), and 4 h (4H) after exercise. All resting samples were taken after 15 min of seated rest. NK (CD3-/56+), activated NK (CD3-/56+/69+), helper T cell (Th; CD3+/4+), and cytotoxic T cell (Tc; CD3+/8+) number were measured by using flow cytometry. NK cell activity (NKCA) was determined by using both a 51Cr release assay (NKCA-51) and activated NK cell number (NKCA-69). Immune system variables were not different between CHO and Pla, with the exception of NK cell responsiveness to IL-2, where Post (116.2%) and 4H (48.4%) was significantly greater in CHO (P < 0.05). NK, Th, and Tc were significantly higher Post (40.7, 102.7, and 82.0%, respectively) and lower at 2H (-51.9, -53.3, and -53.2%, respectively) than Pre (time effect). 4H was not different from Pre for NK, Th, and Tc. NKCA was significantly lower 2H (NKCA-51, NKCA-69) and 4H (NKCA-69) than Pre. CHO consumption during exercise did not prevent disruptions in unstimulated immune system function, but it did enhance NK responsiveness to IL-2.