PhD Project: Recovery of Critical Illness Survivors – incorporating lifestyle approach to improve overall well-being

Undernutrition is a persistent and significant problem for survivors of critical illness, with many continuing to experience inadequate dietary intake well beyond hospital discharge.

Evidence suggests that energy and protein requirements remain unmet for a substantial proportion of patients even one year after leaving the intensive care unit (ICU) (Beumeler, 2024). Although some survivors show gradual nutritional improvements over this period, recovery is inconsistent and often incomplete. Older adults are particularly at risk; Tripathy (2014) found that 48% remained malnourished at 12 months, highlighting the enduring impact of critical illness on nutritional status.

A recent review by Terblanche (2025) identified several prominent barriers to achieving adequate nutrition during recovery. Loss of appetite was reported by 40% of patients and remains one of the most common challenges. Dysphagia affected 26% of survivors, limiting their ability to consume sufficient food, while psychological distress—also affecting 40%—further undermined appetite, motivation, and adherence to nutritional recommendations. These barriers contribute directly to poor dietary intake, with 19% of patients consuming insufficient energy and nutrients. Consequently, malnutrition persists in 42% of survivors, and significant weight loss is experienced by more than half (56%) during the 12 months following hospital discharge.

As advances in ICU care have improved survival rates, the long-term consequences of critical illness have become increasingly visible. Herridge (2011) describes a wide range of physical, functional, and psychosocial impairments reported by ICU survivors, many of which persist for months or years. A key driver of these limitations is intensive care unit-acquired weakness (ICU AW), a condition characterised by severe muscle wasting and reduced muscle strength. ICU AW can develop rapidly during critical illness and continues to impair mobility, independence, and quality of life long after discharge (Bear, 2017). Poor muscle function also limits the capacity for physical activity, further compounding nutritional and functional recovery.

Research investigating body composition changes after ICU discharge has produced mixed findings. Four studies using bioelectrical impedance analysis (BIA) (Rousseau et al., 2022; Ait Hssain et al., 2023; Lakenman et al., 2023; Rives Lange, 2022) reported inconsistent changes in lean and fat mass over time. More precise dual-energy X ray absorptiometry (DEXA) studies found increases in total body mass and fat mass between six and twelve months post-discharge, while lean body mass remained stable or declined. These results suggest that although some survivors regain weight, this often reflects increased fat rather than restoration of muscle, with implications for long-term physical health and function.