Practical Approaches for Interrupting Prolonged Sitting to Improve Postprandial Glucose and Protein Metabolism

The present study will determine the impact of interrupting prolonged sitting with short, 2-minute walks or body-weight squats on: i) postprandial glycemia and insulinemia, and; ii) postprandial utilization of dietary amino acids. We hypothesize that postprandial glycemia and insulinemia will be similarly improved by interrupting prolonged sitting with short walks or body-weight squats, whereas postprandial utilization of dietary amino acids will only be improved by interrupting prolonged sitting with body-weight squats.

Study Overview

• Status: Completed
• Conditions: Healthy Adults
• Intervention / Treatment: Dietary supplement: Mixed-macronutrient meal

Detailed Description

Sedentary behavior is an independent risk factor for chronic disease and premature mortality. Despite a growing awareness of the health risks associated with prolonged sitting, Americans spend upwards of 10 hours per day in a sedentary state. Many leisure-time activities and careers of modern society involve prolonged sitting, necessitating an urgent need to identify strategies that mitigate the health consequences of these behaviors. Recent evidence suggests that interrupting prolonged periods of sitting with short breaks of walking or cycling improve postprandial glucose and lipid handling throughout the day. Thus, relatively small quantities of movement represent an efficacious strategy for improving indices of metabolic health. However, more cost-effective and practical interventions that do not require extra space (i.e. walking) or equipment (i.e. cycling or a treadmill desk) beyond one's immediate sedentary space (e.g. office, desk) would help reduce real and/or perceived barriers of adopting this efficacious disease risk-reduction behavior. A currently understudied consequence of prolonged sitting may also be a desensitization of skeletal muscle's ability to use ingested protein, which overtime can result in detriments to the quantity and quality of this important tissue. Body-weight resistance exercise (RE) can augment the body's ability to use ingested protein to support the maintenance of skeletal muscle mass, and therefore may represent a novel exercise mode to minimize consequences of prolonged sitting. The proposed research will be the first to investigate the influence of interrupting prolonged sitting with short breaks of body-weight resistance exercise (RE) on postprandial glucose and protein metabolism. Importantly, the efficacy of this approach will be directly compared to short breaks of walking, which has previously been reported to improve postprandial glycemia in healthy adults.

• Study Type: Interventional
• Enrollment (Actual): 14
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Toronto, Ontario, Canada, M5S 2C9
      • Goldring Center for High Performance Sport

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 35 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Men and women between 18-35 yr
• Recreationally active (≤ 150 minutes of moderate-intensity physical activity per week and no more than 3 days/week of exercise)
• VO2peak considered "good" or below based on ACSM age and sex normative values
• Experiencing regular menstrual periods and not taking hormonal oral contraceptives (females only)

Exclusion Criteria:

• Inability to perform physical activity as determined by the PAR-Q
• Inability to adhere to protocol guidelines (e.g. alcohol, standardized diet)
• Physical limitations for walking or repeatedly rising from a chair
• Regular tobacco use
• Illicit drug use (e.g. growth hormone, testosterone)
• Hormonal oral contraceptive use (females only)
• Diagnosed medical condition under the care of a physician (e.g. type 2 diabetes)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Sedentary; Sedentary (SED): Participants will remain seated in the lab all-day (7.5 hr).	Dietary supplement: Mixed-macronutrient meal; Participants will be provided a mixed-macronutrient meal (liquid drink) at hours "0" and "3", mimicking the energy and macronutrient composition of breakfast and lunch in Western society (38). 20% of daily energy intake will be provided as "breakfast" and 30% at lunch. Macronutrient composition will reflect a diet providing 55% energy needs from carbohydrate (CHO) and 1.2g/kg/d protein. The remaining energy requirements, as determined by total energy intake, will be met with dietary fat (estimated to be ~0.2 and 0.3g/kg fat for breakfast and lunch, respectively), similar to previous liquid mixed-meal approaches.
Experimental: Walking Breaks; Walking breaks (WALK): Participants will perform 2-minute walking breaks at 3.1 mph on a treadmill every 30 minutes (7.5 hr).	Dietary supplement: Mixed-macronutrient meal; Participants will be provided a mixed-macronutrient meal (liquid drink) at hours "0" and "3", mimicking the energy and macronutrient composition of breakfast and lunch in Western society (38). 20% of daily energy intake will be provided as "breakfast" and 30% at lunch. Macronutrient composition will reflect a diet providing 55% energy needs from carbohydrate (CHO) and 1.2g/kg/d protein. The remaining energy requirements, as determined by total energy intake, will be met with dietary fat (estimated to be ~0.2 and 0.3g/kg fat for breakfast and lunch, respectively), similar to previous liquid mixed-meal approaches.
Experimental: Resistance-exercise breaks; Resistance exercise breaks (RE): Participants will perform 15 "squats" (1-minute) every 30 minutes. To reduce the risk of injury, standardize squat-depth, and recruit similar muscle groups as walking, the squats performed will be a "chair-stand with calf-raise" (7.5 hr).	Dietary supplement: Mixed-macronutrient meal; Participants will be provided a mixed-macronutrient meal (liquid drink) at hours "0" and "3", mimicking the energy and macronutrient composition of breakfast and lunch in Western society (38). 20% of daily energy intake will be provided as "breakfast" and 30% at lunch. Macronutrient composition will reflect a diet providing 55% energy needs from carbohydrate (CHO) and 1.2g/kg/d protein. The remaining energy requirements, as determined by total energy intake, will be met with dietary fat (estimated to be ~0.2 and 0.3g/kg fat for breakfast and lunch, respectively), similar to previous liquid mixed-meal approaches.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postprandial insulin area under the curve (AUC) to breakfast and lunch	The plasma insulin concentration measured by enzyme-linked immunosorbent assay area under the curve will be measured using the trapezoidal rule.	3 hours postprandial

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postprandial glucose area under the curve (AUC) to breakfast and lunch	The plasma glucose concentration measured by hexokinase method area under the curve will be measured using the trapezoidal rule.	3 hours postprandial
Skeletal muscle dietary protein incorporation	[2H5]Phe and [13C6]Phe incorporation into new myofibrillar (contractile) proteins will be determined by LC/MS/MS	7.5 hours postprandial

Collaborators and Investigators

• Sponsor: University of Toronto
• Investigators: Principal Investigator: Daniel Moore, Ph.D, University of Toronto

Study record dates

Study Major Dates

• Study Start (Actual): October 19, 2018
• Primary Completion (Actual): December 1, 2020
• Study Completion (Actual): December 1, 2021

Study Registration Dates

• First Submitted: March 28, 2019
• First Submitted That Met QC Criteria: March 28, 2019
• First Posted (Actual): April 1, 2019

Study Record Updates

• Last Update Posted (Actual): January 19, 2022
• Last Update Submitted That Met QC Criteria: January 18, 2022
• Last Verified: January 1, 2022

More Information

Terms related to this study

• Other Study ID Numbers: SSW

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No