Ambulatory assessment of cardiovascular, electrodermal and electromyographic activity was used to monitor different kinds of strain during eight hours of highly demanding computer work under different work/rest schedules. Eleven patent examiners performed their complex visual display task under two different break regimes in counterbalanced order: 7.5 min break after 50 min work on one day and 15 min break after 100 min work on the other day. Short breaks were more effective in promoting recovery from both mental and emotional strain until the early afternoon, while the long break was more effective in reducing fatigue and emotional strain in the late afternoon. Recovery from muscular strain was greater during scheduled rest breaks compared to unpredictable breaks such as system breakdowns and interruptions by colleagues, but the increase of electrodermal activity was also higher, pointing to the possibility of increased emotional strain as a consequence of a rigid break schedule. Relevance to industry