The Clock Thickens: Morning or Evening Training for the Treatment of NAFLD?

The Clock Thickens: Morning or Evening Training for the Treatment of NAFLD? (TikTac Study)

The goal of this clinical trial is to investigate the different effect of morning and evening exercise training in individuals with non-alcoholic fatty liver disease (NAFLD). The main question it aims to answer is:

• Is morning or evening exercise better for the treatment of NAFLD?

Participants will follow a supervised exercise training program for three months with either morning or evening training and the effect on liver health will be assessed. Researchers will compare the morning to the evening exercise group to see if one training timepoint is more effective than the other in reducing the amount of fat in the liver and improving liver health.

The aim of the study is to identify the effect of exercise timing on NAFLD. Additionally, we aim to increase the understanding of the exercise-related modulation of the metabolic and inflammatory processes causing NAFLD, including insulin resistance and dysbiosis of the gut microbiota. Forty obese patients with NAFLD will be enrolled by randomization to participate in an exercise training program over 12 weeks, either in the morning (n=20) or evening (n=20). Blood and stool samples will be collected before, during and after the intervention to monitor diagnostic markers such as liver enzymes (AST, ALT, GGT, etc.) and changes of the gut microbiota with exercise, respectively. Moreover, mixed meal tolerance tests will be performed before and after the intervention to monitor insulin sensitivity and hepatic fat content and cardiovascular parameters (e.g. arterial stiffness) will be monitored via MRI. Throughout the study, physical fitness will be assessed and monitored using steep ramp tests. Patients will be randomized for a supervised, standardized 50 min morning or evening training, with both progressive endurance and strength elements, in a frequency of 3 times a week for 12 weeks.

Inclusion Criteria:

• Age ≥ 45 years and ≤ 75
• Obese (BMI > 27 kg/m2)
• Males and postmenopausal females
• Caucasian
• Hepatic steatosis defined as increased hyperechogenicity of the liver on abdominal ultrasound, CAP score on Fibroscan > 280, and/or histological signs of steatosis
• Sedentary lifestyle (maximum of 20 minutes of moderate-to-vigorous physical activity per day on less than three days per week)
• Written informed consent

Exclusion Criteria:

• Exclusion criteria for MRI (claustrophobia, pacemaker, metal implants, etc.)
• Any other liver disease than NAFLD/NASH
• Present excessive alcohol use defined as > 2 units/day
• Recent use (< 3 months) of antibiotics
• Recent changes in dosages of regular medication (< 3 months)
• Recent (< 3 months) weight change (>5%)
• Recent (< 3 months) substantial diet changes
• Cardiovascular co-morbidity defined as heart failure, coronary insufficiency and hypertension in past history
• Comorbidity that contraindicates exercise training and exercise testing or that affects exercise response and exercise capacity
• Ongoing or recent use of glucocorticoids, oral/transdermal hormonal substitution, paclitaxel, theofyllin, amiodarone, myelosuppresive agents
• A psychiatric, addictive or any other disorder that compromises the subjects ability to understand the study content and to give written informed consent for participation in the study
• Working night or alternating shifts, known sleeping disorders such as narcolepsy or insomnia