The effect of interval versus continuous exercise on plasma leptin and ghrelin concentration in young trotters

The effect of interval vs. continuous exercise on plasma leptin and ghrelin concentration in young Standardbred horses was studied. The experiment was conducted on 27 trotters, in the age between 2 and 3 years. They were divided into two groups according to the type of exercise. Blood samples were collected through jugular venipuncture in the following experimental conditions: at rest, immediately after exercise and 30 minutes after the end of the effort. Plasma leptin and ghrelin concentrations were determined using RIA tests. The continuous exercise induced an increase in plasma leptin concentration whereas the interval type of exercise did not influence the level of this hormone (3.47 +/- 0.78 vs. 4.07 +/- 0.94 and 2.31 +/- 0.15 vs. 2.36 +/- 0.21 ng/mL, respectively). The plasma ghrelin concentration measured after the continuous exercise, significantly increased (720 +/- 27.4 vs. 814 +/- 13.8; p < or = 0.05) whereas concentration of this hormone assessed after the interval exercise, significantly dropped (982 +/- 56.5 vs. 842 +/- 35.6 pg/mL; p < or = 0.05). The changes in plasma ghrelin concentration measured after the end of the effort correlated inversely with blood lactic acid concentration. In conclusion, the obtained results showed that medium-intensive type of exercise, such as trot, interval or continuous, slightly affected plasma leptin level but significantly affected plasma ghrelin concentration in young Standardbred trotters.