Not taking exercise

It has been a busy week so far and I have been a bit pre-occupied with some work decisions I will have to make soon. I have also been quite tired and I'm about to head for an early bath and bed. Needless to say I have taken no exercise since my big walk at the weekend, which makes me annoyed with myself. I see colleagues going to the gym after work (we are very lucky to have a gym on the premises) but I never join them because I am always busy. I am undoubtedly busy but am I also using it as an excuse? After all I still find time for reading and doing things that I enjoy. I have to make some time for exercise. It won't be tomorrow because I am going on a residential trip. But I will try at the weekend.