Sitting in front of a computer for a long time will make you feel sluggish for a number of reasons — luckily, there's an easy fix for most of them!
Lack of Movement
The main reason that you might feel sluggish after sitting at your computer for a long time is because your body isn't pumping blood fast enough to keep your body well-oxygenated. This can make you feel drowsy and slow. Luckily, exercise will solve this!
Solution: If possible, take a 15-minute break every hour, and keep your body moving during this time (even if you're just walking around the house).
If you're at work, this probably isn't going to happen, so instead, get as much exercise as you can whenever you do leave your desk — even if this means jumping up and down in the toilet cubicle where nobody can see you!
Lack of Stimulation (Or Too Much Engagement With The Same Activity)
This is a major problem for me, although I know it doesn't apply to everyone, and I'm not sure what causes it.
If I'm working on the same thing for a long time, I lose my focus — I'm usually good for about ninety minutes, and then I start to slow down.
My theory is that the brain gets tired of concentrating on the same thing, without any external stimulation (interacting with the real-world environment, or thinking about real-life things, or talking to other people) and stops performing so well.
Solution: Again, taking regular breaks seems to solve this. Even if it's just taking five minutes to make coffee and chat to someone, it's good to get away from the computer and give your eyes a rest.
Uncomfortable Seating Position Or Poor Lighting
If your screen is too low or too high (or too small) then you're probably putting strain on your neck and back.
I never really thought that a good seating position was important until I hurt my neck (completely unrelated) and had to start paying attention to how I was sitting.
Another issue is often screen brightness or flickery overhead lighting. If your eyes hurt, you'll find it hard to concentrate, and this can give you headaches and make you feel slow and sluggish.
Solution: Make sure your screen is level with your eyes, and keep your back as straight as possible. A good chair, close to the desk, works wonders. If possible, make sure your feet are flat on the ground (or can be, if you so choose) and that your forearms are parallel to the desk.
If possible, work under natural light, and turn your screen brightness down if you're going to be using the computer for a long time. After five minutes, you won't even notice the difference!
Neglecting Your Body
Finally, you'll want to make sure you're on top of the following — it can be easy to forget if you're immersed in what you're doing!
- Eat — have you been on the computer for so long that you've forgotten to feed yourself? If you're hungry, you won't find it so easy to concentrate, and you'll have less energy.
- Drink — keep a glass of water on your desk. It's easy to get dehydrated without realising it, and this can make you sluggish.
- Sleep — you might just be feeling sluggish because you're tired. If you think this is the case, take a twenty-minute nap and get back to work!