I would agree with iciek that using headphones, lifeflow or computer programmes at work would be counter productive and lead to more stress in case you are found out doing something your boss would disapprove of.
However, meditating at work is a great thing to do and a great, in the moment stress reliever. You need no headphones, programmes etc.
When stress mounts, just lower your eyes, take a deep breath, hold it just for a moment and then let it go. As you let it go - a bit slower than normal, and without sound, then let the body relax. Especially relax your jaw and your shoulders. Put a half smile on your face - even if it feels fake.
This takes seconds, will not interfere with work, will help you to be more productive and can be repeated ad infinitum without any harm.
peace and joy

H