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Nikos Kokalas

Publications and source records attributed to Nikos Kokalas.

2 recordsLinked to original sources

Effect of aerobic exercise on lipaemia and its fatty acid profile after a meal of moderate fat content in eumenorrhoeic women.

Exercise prior to eating has repeatedly been shown to reduce postprandial lipaemia. The aim of the present study was to investigate whether this effect was manifest in the presence of two factors that independently mitigate postprandial lipaemia: eumenorrhoea and moderate fat intake. Eight healthy eumenorrhoeic rowers consumed a meal of moderate fat content (35 % total energy, 0.66 g/kg body mass) 14 h after having either rowed at 55 % of maximal aerobic power (81 % of maximal heart rate) for 80 min or rested. Both trials were performed during the luteal phase. Blood samples were drawn before the meal and for 8 h postprandially for the measurement of individual fatty acids in the triacylglycerol and NEFA fractions, as well as of glucose, insulin and oestradiol. Plasma oestradiol concentrations were not significantly different in the two trials. The postprandial lipaemic response, expressed as either plasma triacylglycerol concentration or area under the triacylglycerol-time curve, was 35 % lower (P<0.05) after exercise. The postprandial glycaemic and insulinaemic responses were also lower, indicating increased insulin sensitivity, whereas the NEFA response was higher, suggesting a lower entrapment of dietary fatty acids in adipose tissue after exercise. Finally, exercise increased the proportion of unsaturated:saturated NEFA during the postprandial period. In conclusion, aerobic exercise performed 14 h before a moderate-fat meal reduced postprandial lipaemia in women in the luteal phase. This effect shows the potential of exercise to mitigate even moderate lipaemic responses in eumenorrhoeic women.

Adolescent↗

Hormonal responses to three training protocols in rowing.

The aim of this study was to examine the acute responses of serum growth hormone, testosterone, and cortisol to three training protocols in rowing. Six young rowers, members of the national team, carried out three frequently used protocols in rowing, i.e., an endurance, a moderate interval, and a resistance protocol, on separate days in a counterbalanced design. Blood samples were collected before, immediately after, and 4 h after exercise for the determination of growth hormone, testosterone, cortisol, and creatine kinase. All three protocols caused marked increases in growth hormone, the most spectacular being that immediately after the endurance protocol. The change in testosterone concentration immediately after the endurance protocol was significantly higher than the changes after the other two protocols. Cortisol concentration was significantly higher immediately after the endurance protocol than after the other two protocols, but remained relatively low in all cases, suggesting that these protocols did not considerably promote catabolism in muscle tissue. Based on these data, endurance training caused greater responses of the three hormones studied compared to interval or resistance training. In fact, resistance training (at intensities above 85% of 1RM) did not cause any significant changes in the three hormones. We therefore propose that evaluation of training programmes designed for elite athletes should include measurements of hormonal changes in order to ascertain that the programmes do cause the expected adaptations.

Adaptation, Physiological↗