Exercise intolerance, muscle weakness and fatigue complaints are frequent and persistent problems in sarcoidosis. These physical impairments are disabling and affect quality of life in a negative way. The aetiology of these physical impairments is multifactorial. Physical inactivity can cause deconditioning, resulting in more perceived fatigue and muscle weakness. These symptoms may be partially reversible following a structured physical training program. However, scientific studies about physical training in sarcoidosis are lacking. Therefore, the aim of the present study is to examine the changes in fatigue complaints, physical functioning and quality of life (QOL) in patients with sarcoidosis following a 13-week physical training program.

After obtaining written informed consent, sarcoidosis patients will start a 13-week physical training program for three times a week. This training program includes peripheral muscle training for both the upper and lower extremities (starting at 40% of the multiple-repetition maximum) and endurance training consisting of walking on a treadmill (starting at 60% of the speed of the 6-minute walk test) or cycling on a ergometer (starting at 50% of the Wmax).

Participants will be assessed at baseline (week 0), at the end (13 weeks) and 3 months after ending the training. During these assessments, patients perform muscle strength (m. quadriceps and m. biceps) and exercise tests (six-minute walk test and submaximal endurance cycling test). They also complete several questionnaires:

Fatigue Assessment Scale (FAS), World Health Organization Quality of Life assessment instrument-BREF (WHOQOL-BREF), Small Fiber Neuropathy Screening List (SFNSL), Medical Research Council (MRC), Visual Analogue Scale (VAS) and Hospital Anxiety and Depression Scale (HADS)

Inclusion Criteria:

• Patients are diagnosed with sarcoidosis according to the WASOG guideline.
• Fatigued patients ((FAS-score ≥ 22 points) and/or a reduced six-minute walking distance (predicted six-minute walking distance -50 m).
• Patients who signed the consent form and are able to participate in a training program.
• Minimum age 18 years and maximum age 70 years.
• Clinically stable: no exacerbation of complaints, or changes in initiated therapeutic management during the preceding 3 months.

Exclusion Criteria:

• Patients with a cognitive failure, making them unable to understand questionnaires and instructions.
• Patients with a oncological, cardiac, neurological or orthopedic history making them unable to participate in a training program.
• Patients who are unfamiliar with the Dutch language, disabling them to understand questionnaires and instructions.
• Patients who participated in a physical training program six months prior to inclusion.