Effect of Low Intensity Exercise and Protein Intake on Skeletal Muscle Protein Synthesis in Elderly

Study Overview
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Brief Summary
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Maintenance of skeletal muscle mass is crucial during lifespan to retain health and functional autonomy. Sarcopenia, being the loss of muscle mass during aging, is a well-known phenomenon in the elderly and a major challenge viewed from an individual, and a socioeconomic point of view. Nevertheless, several studies have proved muscle tissue to be markedly affected by physical activity and nutritional interventions even at old age. Recently, a study in young individuals showed that an acute bout of easily tolerated low intensity exercise can prolong the muscle building effects of a milk protein intake compared to a non-exercised situation. Therefore, the major aim of the present project is to evaluate, whether a low intensity exercise regime in conjunction with milk protein supplementation can induce positive adaptations on parameters related to muscle size and function in elderly. The study focuses on the acute muscle protein synthesis response to low intensity exercise and protein supplementation measured with stable isotope tracer techniques. It is hypothesized that light muscle activity can augment and prolong the effects of protein feeding. If a light resistance exercise protocol as investigated in the present project can prove beneficial, elderly, frail elderly, and individuals undergoing rehabilitation can challenge sarcopenia in a new and tolerable way.

Official Title
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Impact of Acute Low Intensity Exercise and Protein Intake on Skeletal Muscle Protein Synthesis in Elderly: a Randomized Controlled Trial

Conditions
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Skeletal Muscle Protein Synthesis in Elderly, Protein Kinetics, Sarcopenia

Intervention / Treatment
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* Dietary Supplement: Protein
* Other: Exercise


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male >65 year old Healthy BMI <28 Exclusion Criteria: Smoker Type II diabetic Intake of medicine or supplements which will affect skeletal muscle protein synthesis Alcohol intake >21 units/week. Frequent exercise or hard physical labor

Ages Eligible for Study
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Minimum Age: 65 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Carbohydrate<br> | Other: Exercise<br>* Unilateral low intensity exercise<br>|
| Active Comparator: Protein continous boluses<br> | Dietary Supplement: Protein<br>* Whey protein intake<br>Other: Exercise<br>* Unilateral low intensity exercise<br>|
| Active Comparator: Protein 2 boluses<br> | Dietary Supplement: Protein<br>* Whey protein intake<br>Other: Exercise<br>* Unilateral low intensity exercise<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Skeletal muscle protein synthesis | Measured as myofibrillar fractional synthetic rate (%/hour) in three periods pre intervention: 0-3 hours, 3-7 hours and 7-10 hours | 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Gene expression | Through real time RT-PCR we measure the fold changes in gene expression of targets involved in skeletal muscle remodeling: myogenic factors, atrogenes, matrix related genes | 1.5 years | 
| Intracellular signaling | Through Western Blotting we will measure changes in intracellular hypertrophy signaling. That is the activity of protein targets from the Akt-mTORC1 and Akt-FOXO pathways. | 1.5 years | 
| Amino acid transporter | Through Western Blotting and RT-PCR protein and mRNA expression of amino acid transporters (LAT1, SNAT2, PAT1) are analyzed | 2 years |