✔ 最佳答案
1. Can i do push up after i have my lunch or dinner?
Of course not. You should only do exercise one hour after meal.
2. Now i can only do 20 push up, should i do more?
It really depends on your body strength. You can do more gradually with continuous practice. But you should never try to do more rapidly because you will easily get hurt if you increase the times so quickly.
3. what can i do to make myself more stronger? (except push up and sit up)
The best way of making yourself stronger is to do exercise in the morning. If you cannot then do it in the evening. Jogging is a very good oxegenic exercise because you can start from slow to fast (running). Another good exercise is swimming since you will be training evey piece of muscles of your body.