Table 1 Eligibility of study participants

1. Age ≥ 18 years

2. Expected length of hospitalization ≥72 h

3. New infiltrate on chest X-ray/CT

4. One or more of the following symptoms:

a. Temperature <35 °C or ≥38 °C

b. Cough

c. Dyspnea

d. Pleuritic chest pain

e. Focal chest signs on auscultation

1. Patients unable to give written consent

2. Hospitalization within ≤ 4 days

3. Inability to move their legs

4. Immunosuppression

a. Treatment with ≥20 mg corticosteroids >2 weeks

b. Chemotherapy

c. Neutropenia with neutrophils <0.5 × 10⁹/L

d. Ongoing treatment with biological drugs

e. Chronic HIV-infection with CD4 cell count <350 mio/L

f. Immunosuppression after organ transplantation

5. Terminal ill patients where active treatment is stopped within the first 48 h of admission