 Some of the cognitive - behavioural mechanisms that have been found to play an important role in the maintenance of PCS are unhelpful illness perceptions, maladaptive coping strategies and all-or-nothing behaviour. The all-or-nothing behaviour refers to a behavioural response, where patients overdo things when they believe symptoms are abating and then spend prolonged periods recovering when symptoms reappear. Other patients report a gradual restriction of activity over time, because they fear worsening of symptoms. A promising avenue for treatment seems to be focusing on making sustainable, gradual increases in levels of activity in intensity and or duration over time, and to avoid extreme oscillations. This is often referred to as Graded Exercise Therapy GET, a treatment that can effectively reduce impairment and suffering in chronic fatigue and persistent pain and that can be provided by physiotherapists and hence delivered in a primary care or municipality setting. 