Working on the computer is very tough on your body, which is not used to this modern type of work. Sitting has long been known to cause back pain and negatively influence circulation, which can promote cardiovascular disease. Extensive use of the keyboard and mouse can lead to stiffening of the muscles in your hands, arms, and neck. Staring at a bright screen for too long can cause dry eyes and headaches. So, computer work can be as unhealthy a job as you can imagine.
First and foremost, sitting for long stretches of time is a very serious health risk! Sitting affects your blood circulation, your back experiences a steady stress, you are more likely to drink and eat stuff that isn't good for you, and you burn very little calories, making it more likely that you overeat. As a result, sitting contributes to a host of conditions, most notably gaining weight, diabetes, heart disease, cancer, and consequently a shortened life span.
Second, bad posture causes pain. You can develop bad posture from anything you do habitually, whether it's sitting, standing, or walking. The typical consequences associated with bad posture while working on the computer are pain in the back, shoulder, and neck, often resulting in tension headaches.
Third, staring at the screen causes eye strain. Staring at a bright screen for hours can lead to eye fatigue or eye strain, headaches, blurred vision, burning, itching or tearing eyes, and temporary vision disorders. Fortunately, eye strain rarely results in a permanent condition and symptoms can be prevented or cured rather easily.
Last, but not least, emotional pressure and isolation cause anxiety and depression. Computers are very efficient tools in that they help us with getting more work done in less time. At the same time, you spend less face-to-face time with your colleagues, family, or friends. This can lead to isolation, anxiety, and depression, i.e. both physical and mental health issues. The symptoms are manifold and can include tense muscles, back pain, headaches, poor sleep (insomnia), increased or flat breathing, quickened pulse, and generally signs of stress, depression, or anxiety.