What Lieke ten Brummelhuis and Nancy P. Rothbard discovered when they researched the difference between being an workaholic to working long hours:
Unlike people who merely work long hours, workaholics struggle to psychologically detach from work. And we know that ongoing rumination often goes together with stress, anxiety, depression, and sleep problems, and it impedes recovery from work. Stress levels in workaholics are therefore often chronic, which leads to ongoing wear and tear on the body.
Check their article in the HBR what it means for your health.