These words mean something different to each of us.
Stress - be it emotional or physical, causes the release of cortisol from our adrenal glands. Chronic high levels of cortisol in our blood prevents digestion of food, reduces sex hormone production, reduces thyroid function (slowing metabolism and making us feel sluggish), and blocks the activity of leptin, our fat burning hormone. We need parasympathetic nervous system activation to allow the body to resume optimal metabolic processes. This is the opposite state to stress which is activated by the sympathetic nervous system.
Maybe it is time to place as much importance on some down time just as it is to catch the next CrossFit or Power Yoga class.