The aim of the study is to test the efficacy, feasibility, and safety of a bicycle exercise followed by an intensive lifestyle intervention for 3 months in patients with recent onset and medically untreated type 2 diabetes.

Lifestyle intervention is a fundamental aspect in the treatment of type 2 diabetes. Implementation of lifestyle changes early after diagnosis often suffices to control metabolic dysregulation and may even have a durable impact. However, implementation of these changes is often difficult for multiple reasons including noncompliance as well as doubt on efficacy of sport and diet changes compared to drugs. Furthermore, most patients with type 2 diabetes remain asymptomatic for a prolonged period of time. Thus, they lack an immediate relief of symptoms and do not feel the benefit of changes in lifestyle. Often, untreated type 2 diabetes first manifests itself with symptoms of polyuria and polydipsia. This offers a unique opportunity to demonstrate the potential of lifestyle changes. However, in daily practice, symptomatic patients with polyuria and polydipsia or with HbA1c levels >10% at diagnosis are typically referred to an emergency room, hospitalized and treated with drugs as a first line treatment.

In the present study, we aim to implement a lifestyle intervention as a first-line treatment in recent onset type 2 diabetes. In the emergency room, the bed will symbolically be removed and the patient requested to perform a bicycle exercise. Non-ER patients will be invited to perform the bicycle exercise as soon as possible. We expect from this educational trigger that patients will realize the therapeutic power of sport. Preliminary interventions using this approach at our emergency room demonstrated the potential of such an intervention. However, internal and external validation, efficacy and safety of a lifestyle intervention in an emergency room remain to be shown in a multi-center controlled study.

The primary endpoint of this study is achievement of metabolic control without anti-diabetic medication 3 months after study enrollment. For the purpose of this study, metabolic control is defined as an HbA1c below a target stratified for three groups according to HbA1c at baseline: HbA1c >14% a target of < 10%; HbA1c < 14% and > 10% a target of < 8%; HbA1c < 10% a target of < 7.5%.

Patients will be randomized either to standard care or to a bicycle exercise followed by an intensive lifestyle intervention on top of non-pharmacological standard care.

After rehydration, patients allocated to the intensified lifestyle intervention group will be instructed to perform 30 minutes of bicycle exercise at 60 % of the calculated maximum heart rate (according to Franckowiak et al.) followed by an intensive lifestyle intervention. Patients will be discharged if the clinical status is stable and no comorbidities require further hospitalization. Follow-up visits at the Clinic of Endocrinology for further instructions and consultation will be carried out after 2, 7, 30, 60 and 90 days, half a year and a year.

In order to monitor blood glucose levels, patients will be instructed on visit 2 to take measurements at home and will be asked to send their fasting glucose levels of the first week to the study team for monitoring of the metabolic situation. This will also be done in the week before visits of day 30 and 90.

The schedule for the intervention arm consists of 3 to 5 aerobic training sessions (duration 15-40 minutes each) and 2 resistance trainings per week, as well as weekly motivational coaching via telephone by the study psychologist. Everyday activity will be objectively monitored using the patient's mobile phone and a blinded actigraph (activity tracker). Exercise sessions will be monitored by weekly phone calls and documented. To assess baseline physical activity all patients will fill in the SIMPAQ questionnaire at baseline and at 6 months.

Measurement of clinical parameters (heart rate, blood pressure), venous blood gas analysis (pH, pCO2, base excess, bicarbonate) at baseline and 120 min after beginning of bicycle exercise. Blood glucose levels at baseline and 30, 60 and 120 min after beginning of bicycle exercise. Blood glucose levels, vital parameters, concomitant medication after 2, 7, 30, 60 and 90 days; HbA1c at baseline, 2 (only intervention group), 3 and 6 months and one year; physical activity at baseline, 3 and 6 months. In the intervention group additional self-measurements of blood glucose levels during the first week and within the week before visit at day 30 and 90 after randomization.

Inclusion Criteria:

• Informed consent as documented by signature
• Type 2 diabetes diagnosed within the last two years according to the American Diabetes Association (ADA) criteria
• Age ≥ 18 years
• HbA1c ≥ 7.5 %

Exclusion Criteria:

• Clinically instable patient as defined by the physicians on duty including signs of new cardiac ischemia in the ECG, systolic blood pressure ≥ 200 mmHg, fever ≥ 38.5 °C, symptoms of SIRS or reduced vigilance.
• Anti-diabetic medication for ≥ 24 hours
• Inability to perform a bicycle exercise during 30 minutes
• Previous lifestyle-intervention by an endocrinologist
• Engagement in physical activity more than five times per week
• Enrollment in other interventional study