Influence of Reduced Daily Step Count and Anabolic Interventions on Muscle Protein Metabolism in Older Persons

NCT ID: NCT02347137

Last Updated: 2015-01-27

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 30 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2012-07-31
• Study Completion Date: 2013-05-31

Brief Summary

As the loss of muscle mass with aging is associated with a dysregulation of muscle protein synthesis (MPS) that is generally characterized by an 'anabolic resistance' to nutrients, the primary outcome of the trial is to investigate the effect of a mixed macronutrient beverage on post-prandial myofibrillar MPS. However, the 'anabolic resistance' of aging may be predominantly influenced by the contractile activity of skeletal muscle; for example, the investigators have demonstrated that 2 weeks of reduced habitual activity (i.e. daily step count) induces anabolic resistance in otherwise healthy older adults. In contrast, resistance exercise is well-known to enhance muscle mass and can increase the sensitivity of skeletal muscle to dietary amino acids. Therefore, all participants will undergo a 2-week reduced step count intervention combined with a unilateral leg resistance exercise protocol to induce an 'unhealthy' or 'anabolically resistant' leg and a relatively 'healthy' or 'anabolically sensitive' leg, respectively; this within subject model will be utilized to investigate the effect of the mixed macronutrient beverage in both relatively 'healthy' and 'unhealthy' older muscle. The investigators will also measure changes in muscle mass, muscle function, and cardiovascular health of both legs before and after the 2-week intervention to determine the effect of reduced activity and the protective effect of minimal, low-intensity exercise on these outcomes.

Conditions

Older Adults; Muscle Protein Synthetic Response to Protein; Reduced Physical Activity

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: PREVENTION
• Blinding Strategy: QUADRUPLE

Study Groups

Isolated Whey Protein

20 g isolated whey protein + 15 g non-essential amino acids

Group Type: ACTIVE_COMPARATOR

step-reduction

Intervention Type: OTHER

reduce daily physical activity to less than 1500 steps per day

step-reduction plus resistance exercise

Intervention Type: OTHER

reduce physical activity to less than 1500 steps per day with thrice weekly low-load, high effort resistance exercise

Micellar Whey Protein

20 g micellar whey protein + 15 g non-essential amino acids

Group Type: EXPERIMENTAL

step-reduction

Intervention Type: OTHER

reduce daily physical activity to less than 1500 steps per day

step-reduction plus resistance exercise

Intervention Type: OTHER

reduce physical activity to less than 1500 steps per day with thrice weekly low-load, high effort resistance exercise

Micellar Whey Protein + Citrulline

20 g micellar whey protein + 5 g citrulline

Group Type: EXPERIMENTAL

step-reduction

Intervention Type: OTHER

reduce daily physical activity to less than 1500 steps per day

step-reduction plus resistance exercise

Intervention Type: OTHER

reduce physical activity to less than 1500 steps per day with thrice weekly low-load, high effort resistance exercise

Interventions

step-reduction

reduce daily physical activity to less than 1500 steps per day

Intervention Type: OTHER

step-reduction plus resistance exercise

reduce physical activity to less than 1500 steps per day with thrice weekly low-load, high effort resistance exercise

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Non-smoker

Exclusion Criteria

• Health problems such as: heart disease, rheumatoid arthritis, diabetes, poor lung function, uncontrolled hypertension, or any health conditions that might put the participant at risk for this study
• Failed clearance for exercise participation by the participants family physician/medical doctor
• Failed an exercise strength test.
• Regular consumption of any analgesic or anti-inflammatory drug(s), prescription or non-prescription, chronically will be excluded.
• Taking any medications known to affect protein metabolism (i.e. corticosteroids, non-steroidal anti-inflammatories, or prescription strength acne medications).
• Factors that may exclude a participant from an MRI scan (i.e. various implants, metal in the eyes etc)
• Participants who complete fewer than 5000 steps per day (as assessed by pedometer prior to the study).

• Minimum Eligible Age: 65 Years
• Maximum Eligible Age: 80 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: Yes

Sponsors

McMaster University

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Locations

Exercise Metabolism Research Laboratory, McMaster Univeristy

Hamilton, Ontario, Canada

Countries

Canada

References

Breen L, Stokes KA, Churchward-Venne TA, Moore DR, Baker SK, Smith K, Atherton PJ, Phillips SM. Two weeks of reduced activity decreases leg lean mass and induces "anabolic resistance" of myofibrillar protein synthesis in healthy elderly. J Clin Endocrinol Metab. 2013 Jun;98(6):2604-12. doi: 10.1210/jc.2013-1502. Epub 2013 Apr 15.

Reference Type: BACKGROUND

PMID: 23589526 (View on PubMed)

Burd NA, West DW, Moore DR, Atherton PJ, Staples AW, Prior T, Tang JE, Rennie MJ, Baker SK, Phillips SM. Enhanced amino acid sensitivity of myofibrillar protein synthesis persists for up to 24 h after resistance exercise in young men. J Nutr. 2011 Apr 1;141(4):568-73. doi: 10.3945/jn.110.135038. Epub 2011 Feb 2.

Reference Type: BACKGROUND

PMID: 21289204 (View on PubMed)

Other Identifiers

11-267

Identifier Type: -

Identifier Source: org_study_id