If you are working in the internet excessively, it is not bad only to the different parts of your body, or in your muscles, but also to your eyes and brains. Any excess is a disadvantage. If you think you are using the internet for long, as it is part of your job, might as well you have a water with you to drink for every hour so you have a reason to stand from your chair to pee. You need to bring out the toxins in your body by being and of course by drinking water. Also, staying in sitting position will only lead to muscle pain so you must be always standing as well for a little stretch or movements in your muscle. Also, when you are sitting, make sure to put a habit of having a right sitting position. You should not be slappy. You should be sitting straight at your back and your arms should level your keyboard.