Survival rates of critical illness have increased due to improved facilities and treatment methods in intensive care units. However, surviving critical illness does not automatically mean these patients are cured. In the past, the patients' survival was the measure of success in the treatment of critical illness. Over the past decades, the focus has been shifting towards the quality of life and care needs of these patients after critical illness. Survivors of critical illness frequently suffer from reduced quality of life. Health problems in the recovery period of survivors may predominantly be provoked by the physical consequences of longterm ICU-admission. The physical consequences of critical illness are mostly associated with skeletal muscle wasting during critical illness. This results in a decrease of muscle density up to two percent per day. Some long term physical health problems associated with this phenomenon are fatigue, neuropathy, neuromuscular dysfunction, and changes in bone mineral density. With regards to the long term psychosocial problems in survivors of critical illness there have been reports of short and long-term anxiety, depression and/or posttraumatic stress disorder (PTSD). Further, during and after critical illness, patients may experience delirium and cognitive impairments. In conclusion, survivors of critical illness suffer from long term physical and mental health problems, reflecting in a reduced HRQoL.

Critical illness survivorship is a relatively new and unknown area in research and medical health care. The term post-intensive care syndrome (PICS) has been used to describe the complex aetiology of health deficits following critical illness. A recent Dutch study (the MONITOR-IC-study) with a population of 1729 ICU-patients found that an overwhelming 70 percent of ICU-patients suffer from some form of PICS one year after discharge. Data collected from the specialized post-ICU clinic of the Medical Centre Leeuwarden (MCL) illustrated that 44% of 250 patients that visited this clinic between 2012 and 2018 were unable to sufficiently recover in physical functioning one year after ICU-discharge. Unfortunately, adequate and efficient aftercare programs for ICU survivors are still lacking and patients regularly feel abandoned and insecure after discharge. Personalised healthcare and lifestyle interventions may fulfil this discontinuity in care and improve physical performance and perceived physical health in ICU-patients, followed by improvements in mental wellbeing and HRQoL. Little is known on the effects of optimizing lifestyle on longterm recovery of these patients. Promising results were found in personalised healthcare and lifestyle programs for other patient groups with long-term health problems, such as cancer survivors and patients with diabetes or mental health problems. A Cochrane review showed several exercise rehabilitation programs after ICU-discharge to be feasible, but lacking in overall effect on functional exercise capacity, or on health-related quality of life. This paucity of effect on patient-centred outcomes may be due to inconsistencies in study protocol. However, a lack of adequate nutritional support might be an equally important pitfall. ICU-survivors may experience a number of problems that can hinder their nutritional intake, including lack of appetite, problems with taste and smell perception, and swallowing issues. Recent data from a study on post-ICU nutritional intake showed that of 12 included patients, the majority did not meet their daily caloric and protein intake. Data on nutritional intake after hospital discharge is lacking, but it is likely that patients are unable to achieve these goals without professional support.

Based on this, the investigators hypothesized that, complementary to the standard post-ICU care, a combined lifestyle intervention focussed on exercise and nutritional therapy may improve physical performance and perceived physical health alongside with an improved mental wellbeing and quality of life in long-term ICU-survivors.