Effects of High-intensity Interval Training in Patients With Systemic Lupus Erythematosus

Inclusion Criteria: * ≥18 years old * Fulfilment of the 1982 American College of Rheumatology (ACR) criteria; or 2012 Systemic Lupus International Collaborating Clinics (SLICC/ACR-Damage Index (DI)) classification criteria; or EULAR/ACR criteria; or patients that have received the diagnosis SLE on clinical grounds * Low to moderate disease activity, for example defined as a score of ≤5 in the clinical version of the SLE Disease Activity Index 2000 (SLEDAI-2K), i.e., excluding the serological descriptors (anti-dsDNA positivity and low complement levels) * Low/minimal or no organ damage, for example defined as a score of ≤3 in the SLICC/ACR DI * Stable pharmacological treatment * The ability to perform a maximal ergometercycle exercise test * Be able to read and understand Swedish Exclusion Criteria: * Symptoms or signs of cerebro-vascular disease, pulmonary embolus, pulmonary hypertension, pulmonary fibrosis, cardiovascular disease, angina pectoris, myocardial infarction, dyspnea at rest, uncontrolled blood pressure and uncontrolled diabetes within one year prior to study entry. Chronic kidney disease with * Patients who fulfil the absolute contraindications for maximal exercise testing according to American Heart Association * Patients who cannot perform a maximal ergometercycle exercise test due to the disease * Diseases or other conditions that strongly reduce the ability to exercise or that exercise is not recommended * Patients who perform regular aerobic fitness training and muscle strength exercise sessions at fixed times, \>1 time/week * Pregnancy