Study of Inactivity on Metabolism of Elderly Muscles

Sponsor

McMaster University (Other)

Overall Status

Completed

CT.gov ID

NCT01818609

Collaborator

(none)

Enrollment

Location

Arm

Duration (Months)

0.7

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

Skeletal muscle mass declines with inactivity (casting is a good example) and increases with activity (such as weightlifting). Whether muscle mass increases or decreases, is determined by whether more new proteins within muscle are made than are broken down. The investigators know that feeding protein increases the synthesis of new proteins but that the response of older muscles to protein feeding is blunted compared with the young. This resistance of the elderly to muscle building stimuli may be the primary reason that muscle mass is lost in aging. The investigators also know that periods of muscle disuse such as casting result in a person's muscle shrinking due, the investigators believe, to a lower rate of synthesis of new muscle proteins. Age-related muscle loss begins around 50 years old and proceeds at approximately 1% for every year after. Elderly persons would likely fare well with advancing age if their muscle loss were simply linear; however, a rate of muscle loss of 1% annually is a 'population view' and does not represent what occurs during short periods of muscle disuse (i.e. during hospitalization or illness), which occur with increasing frequency in elderly persons. During periods of disuse, the resistance of elderly muscles to protein nutrition may be worsened. The investigators will measure how quickly new proteins are made at rest and after protein feeding in elderly men, before and after a 14 day period of reduced activity brought on by having people reduce their daily step count.

Condition or Disease	Intervention/Treatment	Phase
Sarcopenia	Behavioral: Step reduction	Phase 1

Study Design

Study Type:

Interventional

Actual Enrollment :

10 participants

Allocation:

N/A

Intervention Model:

Single Group Assignment

Masking:

None (Open Label)

Primary Purpose:

Basic Science

Official Title:

Influence of Reduce Daily Step Count on Muscle Protein Metabolism in Older Persons

Study Start Date :

Sep 1, 2011

Actual Primary Completion Date :

Sep 1, 2012

Actual Study Completion Date :

Dec 1, 2012

Arms and Interventions

Arm	Intervention/Treatment
Experimental: Step Reduction Step reduction: Take less than 1500 steps/d No disease	Behavioral: Step reduction taking less than 1500 steps/d Other Names: Sedentary behaviour

Arm

Intervention/Treatment

Experimental: Step Reduction

Step reduction: Take less than 1500 steps/d No disease

Behavioral: Step reduction

taking less than 1500 steps/d

Other Names:

Sedentary behaviour

Outcome Measures

Primary Outcome Measures

Fractional synthetic rate (FSR) of myofibrillar muscle protein [over 5h]
rate of making new muscle proteins

Secondary Outcome Measures

Blood amino acid concentrations [over 5h]
concentration of amino acids in blood
Intramuscular signalling protein status [over 5h]
phosphorylation of key signalling proteins
Insulin sensitivity via blood sampling [over 5h]
measure of insulin concentration

Eligibility Criteria

Criteria

Ages Eligible for Study:

60 Years to 80 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Yes

Inclusion Criteria:

Male or Female
Aged 60 to 80 years old
Non-smoker Generally healthy and can tolerate the resistance exercise and protein drink

Exclusion Criteria:

Allergies to whey protein
Health problems such as: heart disease, rheumatoid arthritis of the knee joint, diabetes, poor lung function, uncontrolled hypertension, or any health conditions that might put participants at risks for this study
Failed an exercise stress test
Taking metformin and/or other medications for the control of blood glucose even though one might not be classified as diabetic
Taking prescribed blood thinners such as warfarin and heparin but excluding aspirin
Taking medications for lung and kidney conditions but excluding medication for asthma that is under control