A good rule of thumb is to accumulate around 30 minutes of activity every day if you are feeling up to it, but the great thing is that you do not need to do all of these 30 minutes at one time, you can split it up throughout your day. So depending on how energetic you are or how much time you have, 30 minutes is a safe and effective amount to work towards. You can always do more each day but try not to overdo it because it could cause you to end up in bed afterwards for 2-3 days. Do slightly less than you want to do on a good day; this is a safe standard.