Shyness in a child can be a source of anxiety
for both you and your son. Fortunately at that age of 7, there are so many developmental stages for him to pass through and his overall social prognosis on average is quite good. You child's pediatrician
likely deals with this type of parental question all the time and give you an answer that better fits with your son's particular situation. Exercises can mean several different things. If you mean physical exercise, then the best exercise that will encourage him to socialize is an organized sport or game. For a child his age, I would recommend soccer or baseball. You can start by playing one of those sports at home with your son to see which one he likes. Sports at that age are great for forcing kids into social situations that the may find quite pleasing. Another strategy would be to arrange a day out with one of your son's classmates in elementary school doing something fun like going to the park or the movies. Any type of exercise that forces him into social situations in a safe way and shows him that they are not that scary. At your next checkup, bring the issue up with his pediatrician. He or she will have other advice that may be more sensitive to your specific life situation. Good luck.