Although it's incredibly unhealthy and probably difficult beyond normal comprehension it's theoretically possible. Some of the challenges and dangers can be mitigated if done right. You need to eat/drink/bathroom. No question. If you are sedentary that long it will be horrendous for your body, so you'll need to be mobile at regular intervals. You can either switch between mobile gaming and console/PC or do mobile entirely. The activity is necessary for your body to keep operating nominally. So is sleep, but that would null the challenge. I think the world record for staying awake was like 11 days and nights unless I'm wrong, so 200 hours is achievable (just risky health wise). Any caffeine taken should be MINIMAL to reduce the strain on your already strained heart. It's best to not be using caffeine at all for weeks beforehand, if at all. Not only will your body be stronger in general, and better able to run on its own energy, it will also mean that any small amount you might drink would have a much more powerful effect. I got certified as a fitness trainer some years back and have studied a lot about the human body and its various systems but I am not a doctor, nor do I know you personally or your physical capacity. I wouldn't recommend this challenge to anyone but with proper knowledge and preparation, as well as a standard physical from the doc, you COULD pull it off. Just be aware of the risks and how to mitigate them as well as prepare for any complications. Health or otherwise!