Cutting down to the chase, exercise increases serotonin levels in the brain. This resulting in mental clarity..Leading to a much productive day. People who workout are much more productive at work than those who don't. This means you will be a better worker, everything better at the work place. You will also have more energy to interact with people. You will come across as friendly and have more stamina for any task your requires. But yes, exercise makes you more tired at first but that wont last for long so you just have to get a little extra sleep in the beginning.
Good Luck at Your Goals!