The Impact of Short Term High Intensity Exercise and Overfeeding on Total PYY Concentrations

It is still unclear whether seven days high intensity exercise or overfeeding has an impact on the circulating fasting total peptide YY (PYY) concentrations and subjective appetite when the energy intake in an overfeeding trial is equivalent to energy expended during an exercise trial. PURPOSE: The objective of this study was to investigate the effect high intensity exercise and overfeeding on fasting total PYY concentrations and subjective feelings of hunger and fullness. METHODS: Twelve males age between 19 and 22 years participated in this study, which had been approved by the local ethics committees (body weight, 59 ± 2 kg; body mass index, 20±1 kg/m2; total percent body fat, 12 ± 1 %; total fat free mass, 52 ± 1 kg ; resting heart rate, 64 ± 3 beat/min; systolic /diastolic blood pressure, 121 ± 3 /69 ± 2 mmHg; maximum oxygen consumption, 55 ± 2 ml/kg/min: mean ± SE). The experiment was a randomized cross-over design with three main trials including control, exercise, and overfeeding trials. On exercise trial, participants were ran on a treadmill at 70% of VO2max for 60 minutes a day for seven days. On overfeeding trial, participants were consumed extra food which is the same amount of energy expended during exercise trial for seven days. Fasting total PYY concentrations were measured using enzyme-linked immunoassay on day one and day eight in three main trials. Subjective feelings of hunger and fullness and rate of perceived exertion were assessed over a period of time. The data were analyzed using two way repeated measures ANOVA and paired t-test. RESULTS: Fasting total PYY concentrations did not change following short term high intensity exercise (before: 159 ± 10; after 166 ± 14 pg/ml) and overfeeding (before: 164 ± 9; after 174 ± 11 pg/ml). There was no difference in subjective feelings of hunger and fullness between three trials. However, high intensity exercise induced increasing in rate of perceived exertion over seven days. CONCLUSION: There was no impact of short term either high intensity exercise or overfeeding on fasting total PYY and the subjective feelings of hunger and fullness. Future research should focus on long term effect of high intensity exercise and overfeeding on appetite hormones.