Similar to ear blockage, this effect tends to happen after strenuous activity.
According to several studies, high-intensity exercise leads to lower levels of a hormone called ghrelin, which is known to stimulate appetite.
For example, in a study published in the International Journal of Obesity, relatively healthy but slightly overweight men performed four workouts of varying intensity over four days.
Researchers found that, after rigorous exercise, the subjects' appetites were noticeably weakened. On the most strenuous days, they had significantly lower levels of ghrelin, elevated blood lactate and higher blood sugar—all of which have been shown to reduce the desire to eat.
Depending on the person and his or her fitness level, gender and body composition, the appetite suppressing effect can last for 60 to 90 minutes, or even into the next day.