Exercise Intensity and Postprandial Effects of Breaking Sedentary Behavior in Overweight Adults

Hacettepe University

Status: Not yet enrolling

Conditions: Postprandial Metabolism; Exercise Physiology; Substrate Oxidation; Cardiovascular Risk Markers

Treatments: Other: Sedentary Behaviour Intervention; Other: Sprint Exercise Intervention; Other: Aerobic Exercise Intervention

Study type: Interventional

Funder types: Other

Identifiers

NCT07229963

SBA 25/679

Details and patient eligibility

About

The purpose of this study is twofold: (1) to determine whether breaking up prolonged sitting with aerobic or sprint cycling breaks reduces postprandial blood glucose, insulin, CRP, and blood pressure, which are established risk markers for cardiometabolic diseases; and (2) to assess substrate oxidation during this period in order to identify which exercise condition promotes the greatest increase in fat oxidation.

Full description

Sedentary behavior (SED) refers to activities such as sitting, lying down, or reclining that require energy expenditure of ≤1.5 MET during the time spent awake. Prolonged and continuous sedentary behavior leads to adverse effects such as abnormal postprandial metabolic responses, insulin resistance, vascular dysfunction, high blood pressure, increased carbohydrate oxidation, and inflammation. Epidemiological data also show that SED increases the risk of mortality, cardiovascular disease, type 2 diabetes, and certain types of cancer. Experimental studies have shown that 2-5 minutes of low- or moderate-intensity aerobic exercise performed every 20-30 minutes during the postprandial period improves cardiometabolic health by reducing glucose, insulin, and blood pressure during the postprandial period. On the other hand, it is known that short-term sprint interval exercise (SIE) increases insulin sensitivity by rapidly depleting muscle glycogen, improves glucose control, lowers blood pressure, and increases fat oxidation. With these effects, SIE may be a time-efficient method for interrupting SED. Although the cardiometabolic benefits of SIE and aerobic exercise interruptions (AEI) are known, there is a lack of studies comparing the effects of interrupting SED with these two exercise types of different intensities in preventing postprandial cardiometabolic dysfunction. In this context, the aim of the study is to compare the postprandial cardiometabolic effects of interrupting sedentary behavior with AIE and sprint exercise interruptions (SEI) in overweight but otherwise healthy women and men aged 35-45. In this randomized crossover trial, volunteers will participate in three trials: 1) AEI, 2) SEI, and 3) SED. There will be a minimum 3-day washout period between trials. In the SEI and AEI trials, exercise interruptions will be implemented every 30 minutes during the 7-hour sitting period, whereas in the SED trial, participants will remain seated continuously for the entire duration. In all conditions, two meals (breakfast and lunch) will be served 3 hours apart, and the trials will begin, after the breakfast meal is consumed. Venous blood samples taken hourly during the experiment will be used to analyze insulin, glucose, and C-reactive protein (CRP) levels. In addition, blood pressure will be measured hourly, and fat oxidation will be assessed at the baseline, 2nd, 5th, and 7th hours. The effects of the conditions on glucose and insulin will be evaluated using linear mixed models. A Two-Way (Trial x Number of Repeats) Analysis of Variance for Repeated Measures will be used to detect differences between conditions.

Enrollment: 16 estimated patients

Sex: All

Ages: 35 to 45 years old

Volunteers: Accepts Healthy Volunteers

Inclusion and exclusion criteria

Inclusion Criteria

• Being physically inactive (not doing at least 150 minutes/week of structured exercise).
• Having a physical activity level of <5000 steps/day.
• Having a BMI between 25 and 29.9 kg/m2.
• Having a history of regular menstrual cycles for female participants.
• Having medical examination approval.

Exclusion Criteria

• Taking any acute or chronic medication or supplement that may affect metabolism.
• Having an acute or chronic illness that limits exercise (musculoskeletal problems, cardiovascular disorders, respiratory problems, etc.).
• Consuming tobacco products.
• Meeting 3 or more of the metabolic syndrome criteria (waist circumference of 102 cm or more in men, 88 cm or more in women, triglyceride level of 150 mg/dL or higher, HDL cholesterol level below 40 mg/dL in men and 50 mg/dL in women, blood pressure of 130/85 mmHg or higher, fasting blood glucose level of 100 mg/dL (5.6 mg/L) or higher).

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: None (Open label)

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16 participants in 3 patient groups

Sedentary: Participants will remain seated for 7 h.

Experimental group

Description:

The sedentary condition will take place in a seated position. During the seated condition, volunteers will be seated at a typical desk chair at an appropriate height with hip and knee angles of \~90° and feet flat on the floor. The seating area will include a standard desk chair, a work desk, and the volunteers' personal laptops. Volunteers will be instructed prior to the visit to avoid behaviors such as fidgeting, excessive leg movements, and crossing their legs to minimize potential extraneous effects.

Treatment:

Other: Sedentary Behaviour Intervention

Breaking up sitting with aerobic exercise interruptions

Experimental group

Description:

The protocol that will interrupt sitting with AEI will involve cycle exercises performed at 50% of VO2max for 2 minutes. The W and rpm levels corresponding to 50% of VO2max will be determined using the values recorded during the determination of VO2max.

Treatment:

Other: Aerobic Exercise Intervention

Breaking up sitting with sprint exercise interruptions

Experimental group

Description:

The protocol that will interrupt sitting with SEI will involve cycle exercises performed at the maximum revolutions per minute achievable within 10 seconds. Immediately before each SEI, volunteers will increase their pedal cadence to the maximum speed they can achieve, after which a pedal load will be applied to the bicycle ergometer and a sprint will be performed against the applied load for 10 seconds. During each sprint, the pedal load will be applied at 0.065 kilograms per kilogram of lean body mass. Since it has been shown to lead to greater peak power output in overweight and obese groups, lean body mass will be used as a reference when determining pedal load, rather than total body mass.

Treatment:

Other: Sprint Exercise Intervention