thank you for the query .
Every thing you practice is very good for your health.
may be due to some extra calories you are taking comparing your daily activities.
this may be taken care of by doing some power exercise and taking advice from physical trainer .
may be due to some g i disturbance giving rise to indigestion
if the flatulence persists please get a consultation with physician and get advice.
and spicy food will help reducing flatulence.
hope you remain fit and healthy.