Sitting at a desk all day without enough breaks to get up and walk around is bad for your health.
Sitting too long can cause blood clots as well as cause weight gain which is not good.
I used to sit at a desk all day with a few 20 minute breaks through the day or until I had to pee or use the bathroom.
Bust most of my day was sitting at the desk for 8 hours per day and eventually I started gaining weight because a desk job means you have to sit a lot which increases your weight for some people.
Also I noticed I was getting blood clots and so I went to the doctor for the blood clots and they said that sitting at the desk most of the day was never good and could lead to those blood clots.
You need to move your body around to keep your heart pumping properly and keep your blood flowing properly as well.
I now work at home and although I still sit at the desk sometimes I get more breaks when I want too and I've lost weight and don't suffer blood clots anymore.
I now can get up from the desk and walk away for a break whenever I want and can take a walk around town etc.
With a job where I had a boss I could not do that or get fired.