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Effect of time of day on homonal response to weight lifting exercise
The effects
of a nucleotide
supplement
on Salivary
IgA and
Cortisal
after endurance exercise L. McNaughton*~& D. Bentley2 ~UniversityOf Hull,Hull,UnitedKingdom 2Universityof Westminster
AIM: The aim of this work was to determine the ergogenic effects of a nucleotide supplement on salivary immunoglobin A (IgA) and cortisol (C) responses after prolonged endurance cycle exercise. METHOD: Fourteen moderately trained male subjects (Mean body mass and VO2max) completed two 90 min cycle ergometer trials (60% VO2max) prior to and after 60 days of either a nucleotide (E) (n=7) or placebo (P) (n=7) supplement. Each of the subjects provided an unstimulated saliva sample prior to and following the exercise for determination of salivary IgA and C. RESULTS: Salivary IgA was significantly lower after exercise trials in both E and P groups (p<0.000) before and after the experimental period. However, salivary IgA was significantly higher (p<0.01) in the E group than the P group after supplementation. Pre-exercise C levels were not different between E and P either prior to or after supplementation (p>0.11). Post exercise cortisol C concentrations were significantly (p<0.001) higher than pre-exercise levels in both groups of subjects. After the supplementation period, C concentration was significantly (p<0.0001) lower after exercise in E compared to P. CONCLUSION: This work suggests that a nucleotide supplement, given chronically may offset the hormonal response associated with demanding endurance exercise. Effect
of time
of day on homonal
response
to weight
lifting
exercise S. Bird*&K. Tarpenning CharlesSturtUniversity,Bathurst,Australia
Research indicates that concentration of specific hormones in the body follow circadian rhythms, with nocturnal sleep characterised by distinct patterns of hormonal secretion. Both testosterone (T) and cortisol (C) exhibit a circadian rhythm with highest concentrations in the morning and lowest in the evening. Testosterone is a potent stimulator of protein and may possess anti-catabolic properties within skeletal muscle. Moreover, modification of the cortisol response could influence protein turnover by altering the balance between hormone-mediated anabolic and catabolic activity. Physiological reactions of these hormones and training adaptations may influence the postexercise recovery phase by modulating anabolic and catabolic processes, therefore affecting the metabolic equilibrium. This may lead to intensification of catabolic processes. Thirteen young (mean 21.8 years; range 18-28) weight trained men (12mths training experience) performed an eight-station weight-lifting protocol on two separate occasions (AM 0600h and PM 1800h), completing 3 sets of 8-10 repetitions, at 75% of their 1-RM On each occasion blood samples were obtained prior to, during and following the exercise bout. Serum total T and C concentrations were determined by competitive immunoassay technique. The current investigation reported significantly lower (P<0.05) pre-exercise C concentrations during the PM session, which resulted in a lower acrophase. The accompanying increased T/C ratio is suggestive of a reduced catabolic environment. This altered balance may better favour the conservation of myofibrillar protein, enhancing skeletal muscle growth by suppressing protein degradation as the primary mechanism, therefore optimising the skeletal muscle hypertrophic adaptations that are associated with weightlifting exercise.
29
of a nucleotide
supplement
on Salivary
IgA and
Cortisal
after endurance exercise L. McNaughton*~& D. Bentley2 ~UniversityOf Hull,Hull,UnitedKingdom 2Universityof Westminster
AIM: The aim of this work was to determine the ergogenic effects of a nucleotide supplement on salivary immunoglobin A (IgA) and cortisol (C) responses after prolonged endurance cycle exercise. METHOD: Fourteen moderately trained male subjects (Mean body mass and VO2max) completed two 90 min cycle ergometer trials (60% VO2max) prior to and after 60 days of either a nucleotide (E) (n=7) or placebo (P) (n=7) supplement. Each of the subjects provided an unstimulated saliva sample prior to and following the exercise for determination of salivary IgA and C. RESULTS: Salivary IgA was significantly lower after exercise trials in both E and P groups (p<0.000) before and after the experimental period. However, salivary IgA was significantly higher (p<0.01) in the E group than the P group after supplementation. Pre-exercise C levels were not different between E and P either prior to or after supplementation (p>0.11). Post exercise cortisol C concentrations were significantly (p<0.001) higher than pre-exercise levels in both groups of subjects. After the supplementation period, C concentration was significantly (p<0.0001) lower after exercise in E compared to P. CONCLUSION: This work suggests that a nucleotide supplement, given chronically may offset the hormonal response associated with demanding endurance exercise. Effect
of time
of day on homonal
response
to weight
lifting
exercise S. Bird*&K. Tarpenning CharlesSturtUniversity,Bathurst,Australia
Research indicates that concentration of specific hormones in the body follow circadian rhythms, with nocturnal sleep characterised by distinct patterns of hormonal secretion. Both testosterone (T) and cortisol (C) exhibit a circadian rhythm with highest concentrations in the morning and lowest in the evening. Testosterone is a potent stimulator of protein and may possess anti-catabolic properties within skeletal muscle. Moreover, modification of the cortisol response could influence protein turnover by altering the balance between hormone-mediated anabolic and catabolic activity. Physiological reactions of these hormones and training adaptations may influence the postexercise recovery phase by modulating anabolic and catabolic processes, therefore affecting the metabolic equilibrium. This may lead to intensification of catabolic processes. Thirteen young (mean 21.8 years; range 18-28) weight trained men (12mths training experience) performed an eight-station weight-lifting protocol on two separate occasions (AM 0600h and PM 1800h), completing 3 sets of 8-10 repetitions, at 75% of their 1-RM On each occasion blood samples were obtained prior to, during and following the exercise bout. Serum total T and C concentrations were determined by competitive immunoassay technique. The current investigation reported significantly lower (P<0.05) pre-exercise C concentrations during the PM session, which resulted in a lower acrophase. The accompanying increased T/C ratio is suggestive of a reduced catabolic environment. This altered balance may better favour the conservation of myofibrillar protein, enhancing skeletal muscle growth by suppressing protein degradation as the primary mechanism, therefore optimising the skeletal muscle hypertrophic adaptations that are associated with weightlifting exercise.
29