Evaluation of the relationship between maximal aerobic capacity and metabolic flexibility in response to fasting glucose/insulin in humans (Evaluación de la relación entre la capacidad aeróbica máxima y flexibilidad metabólica en respuesta a ayuno prolongado e infusión de glucosa/insulina en humanos)

• Register: ISRCTN
• Last refreshed on: 22 June 2020
• Main ID: ISRCTN88318437
• Date of registration: 31/10/2017
• Prospective Registration: No
• Primary sponsor: Fondecyt
• Public title: Evaluation of the relationship between maximal aerobic capacity and metabolic flexibility in response to fasting glucose/insulin in humans (Evaluación de la relación entre la capacidad aeróbica máxima y flexibilidad metabólica en respuesta a ayuno prolongado e infusión de glucosa/insulina en humanos)
• Scientific title: Evaluation of the relationship between maximal aerobic capacity and metabolic flexibility in response to fasting glucose/insulin in humans
• Date of first enrolment: 12/09/2017
• Target sample size: 20
• Recruitment status: Completed
• URL: http://isrctn.com/ISRCTN88318437
• Study type: Interventional
• Study design: Interventional single-center randomized crossover trial (Other)
• Phase: Not Applicable

Countries of recruitment

Chile

Contacts

• Name: Jose Galgani Fuentes

Key inclusion & exclusion criteria

Inclusion criteria:
1. Healthy men (by physical examination, past and current medical history, and routine blood testing, including biochemical profile, thyroid-stimulating hormone, free thyroxine, electrolytes, creatinine, and hemogram)
2. Between 18 and 35 years old
3. IMC: 18.5 – 25 kg/m2
4. Stable body weight (change<2 kg over the past 3 months)
5. Physical activity (<3 days/week)
6. Do not take medications

Exclusion criteria:
1. Men with any disease
2. Younger than 18 years old and older than 35 years old
3. Unstable weight (change>2 kg over the past 3 months)
4. Physical activity (>3 days/wk)
5. Taking medications


Age minimum:
Age maximum:
Gender: Male

Health Condition(s) or Problem(s) studied

Metabolic flexibility and maximal aerobic capacity in healthy subjects
Nutritional, Metabolic, Endocrine

Intervention(s)

In the selected individuals, the maximum aerobic capacity (by indirect calorimetry) and lactate threshold (by concentration in lactate venous blood) in an exercise bicycle will be determined. On a second visit (4-7 days later), subjects will be randomly allocated to undergo either a 20-hour fasting session or a hyperinsulinemic, euglycemic clamp session. 10 volunteers will be assigned randomly to the fasting session for their first measurement and 10 will be assigned to the clamp session for their first measurement. The exercise session will be held before or after, but all volunteers must complete all three sessions.

In the fasting session, an intravenous line will be placed in the vein of an arm. After 30 minutes of rest and 12 hours of fasting, the gas exchange will be evaluated for 20 min by indirect calorimetry. During the measurement two blood samples (glucose, lactate, free fatty acids, triglycerides, VLDL, 3-OH-butyrate and insulin) will be extracted with an interval of 10 min between them. At the end of the calorimetric measurement the line will be removed, and the volunteer will remain at rest for 7 hours. At the end of the rest, an intravenous line will be installed and the calorimetric measurement will be performed for 20 min. During this period two blood samples (glucose, lactate, free fatty acids, triglycerides, VLDL, 3-OH-butyrate and insulin) will be extracted with an interval of 10 min between them.

In the euglycemic-hyperinsulinemic clamp session, individuals will attend under nighttime fasting conditions. An intravenous line will be installed in both arms. After 30 minutes of absolute rest and 12 hours of fasting, the gas exchange will be evaluated for 20 min by indirect calorimetry. During the measur

Primary Outcome(s)

1. Resting metabolic rate and respiratory quotient, measured by indirect calorimetry at two of three sessions with an interval of 4-7 days during the month following the selection
2. Glucose metabolic flexibility, measured by euglycemic-hyperinsulinemic clamp
3. Maximal aerobic capacity, measured by indirect calorimetry and a blood sample for lactate concentration in venous blood during exercise for 15 minutes. This measurement is performed during the month following the selection

Secondary Outcome(s)

1. Glucose, lactate, free fatty acids, triglycerides, VLDL, 3-OH-butyrate and insulin concentration, measured by taking two blood samples with a 10-minute interval before and after the clamp
2. Body mass and body composition, measured using the body mass index formula (BMI) and electrical bioimpedance

Secondary ID(s)

1170117

Source(s) of Monetary Support

Pontificia Universidad Católica de Chile (Santiago)

Ethics review

Status:
Approval date:
Contact:

Ethics Board at Pontificia Universidad Católica de Chile, 08/06/2017, ref: 1170117

Results

• Results available: Yes
• Date Completed: 08/01/2018