This study will investigate the influence of increased sedentary time on long-term measures of muscle protein synthesis and metabolic health. The investigators will test the hypothesis that increased time spent in sedentary behaviours will lead to a reduction in long-term measures of muscle protein synthesis and compromised metabolic health.
Sarcopenia, the loss of muscle mass with age, is thought to be accelerated by an inactive, sedentary lifestyle. Increased sedentary time has consistently been associated with lower muscle mass and compromised metabolic health. However, there is currently a lack of direct evidence to support these associations. Therefore, this study will investigate whether increased sedentary time (reduced step count and exercise cessation) directly influences long-term measures of muscle protein synthesis and metabolic health in young, active adults. Following a 7 day period of normal habitual physical activity, participants will undertake a 7 day period of step reduction and exercise cessation. It is hypothesised that 7 days of increased sedentary time will result in a reduction in long-term rates of muscle protein synthesis and a worsening of metabolic health.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
8
Young, active participants will undergo a 7 day period of habitual physical activity followed by a 7 day period of step reduction and exercise cessation.
School of Sport Exercise and Rehabilitation Sciences, University of Birmingham
Birmingham, United Kingdom
Muscle protein synthesis (FSR %/day)
Long-term muscle protein synthesis (FSR %/day) will be determined using deuterium oxide (D2O) to compare muscle protein synthesis rates over the first 7 day period and the second 7 day period.
Time frame: 0-14 days
Rate of fat oxidation at rest (g/min)
Whole body oxygen consumption (VO2, L/min) and carbon dioxide production (VCO2, L/min) at rest will be measured using indirect calorimetry to calculate the rate of fat oxidation at rest (g/min).
Time frame: For 20 minutes at day 7 and day 14
Rate of fat oxidation during an oral glucose tolerance test (g/min)
Whole body oxygen consumption (VO2, L/min) and carbon dioxide production (VCO2, L/min) following an oral glucose drink will be measured using indirect calorimetry to calculate the rate of fat oxidation during an oral glucose tolerance test (g/min).
Time frame: At 0, 30, 60, 90 and 120min of the oral glucose tolerance test at day 7 and day 14
Rate of carbohydrate oxidation at rest (g/min)
Whole body oxygen consumption (VO2, L/min) and carbon dioxide production (VCO2, L/min) at rest will be measured using indirect calorimetry to calculate the rate of carbohydrate oxidation at rest (g/min).
Time frame: For 20 minutes at day 7 and day 14
Rate of carbohydrate oxidation during an oral glucose tolerance test (g/min)
Whole body oxygen consumption (VO2, L/min) and carbon dioxide production (VCO2, L/min) following an oral glucose drink will be measured using indirect calorimetry to calculate the rate of carbohydrate oxidation during an oral glucose tolerance test (g/min).
Time frame: At 0, 30, 60, 90 and 120min of the oral glucose tolerance test at day 7 and day 14
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Blood glucose concentration
Blood glucose concentration will be assessed in blood samples taken during the oral glucose tolerance test.
Time frame: At 0, 30, 60, 90 and 120min of the oral glucose tolerance test at day 7 and day 14
Blood insulin concentration
Blood insulin concentration will be assessed in blood samples taken during the oral glucose tolerance test.
Time frame: At 0, 30, 60, 90 and 120min of the oral glucose tolerance test at day 7 and day 14
Blood fatty acid concentration
Blood fatty acid concentration will be assessed in blood samples taken during the oral glucose tolerance test.
Time frame: At 0, 30, 60, 90 and 120min of the oral glucose tolerance test at day 7 and day 14