Sarcopenia describes the progressive decline of muscle mass and strength with advancing age and is associated with increased frailty and morbidity, however we do not currently have an effective treatment. Protein feeding and exercise is known to increase muscle mass, but aged muscle shows a lower response to these stimuli leading to muscle loss over time. We do know that ingesting leucine, a building block of protein, can overcome this reduced response to protein feeding and exercise leading to increased muscle mass in older people. However, we do not understand when the optimum time to ingest leucine is to maximise muscle mass after exercise in older people. In this study we will examine the effect of feeding leucine after exercise either with a meal or between meals.
Male, 65-75 years of age
BMI 18-28 kg/m2
Non smoker
Not performing regular resistance type exercise
A BMI <18 or >28 kg·m-2
Active cardiovascular disease: uncontrolled hypertension (BP > 160/100), angina, heart failure (class III/IV), arrhythmia, right to left cardiac shunt or recent cardiac event
Cerebrovascular disease: previous stroke, aneurysm (large vessel or intracranial)
Respiratory disease including pulmonary hypertension or chronic obstructive pulmonary disease (COPD)
Crossover
Leucine
Dietary supplementLeucine is a dietary supplement that can be easily purchased over the counter at health food stores. It is an essential amino acid and is involved in stimulate muscle protein synthesis.
Muscle protein synthesis in response to leucine feeding
To quantify muscle protein synthesis in response to feeding leucine with a meal or in-between meals using mass spectrometry.
Measure muscle anabolic and catabolic signalling pathways in response to leucine feeding
To determine the impacts of leucine feeding timings on muscle anabolic and catabolic signalling pathways using western blotting techniques.
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