Ageing - Nutrition And PA Flashcards
What are the common physiological consequences of ageing?
Loss of muscle mass, Decline in muscle function, Decline in VO2 max and CRF (changes in ventilatory and CV function) Decline in power, Decline in fibre size and number, Changes to body composition, Sarcopenia, Composition of muscles, Decline in muscle strength,
Whats the typical decline rate of muscle mass?
0.5-1% p/yr, accelerating after 65 yrs.
When accompanied by disuse, more rapid decline
Leads to ‘threshold of disability’
Which kind of fat is more prevalent in older adults and why is this bad?
Visceral and ectopic fat.
Older adults are less able to utilise this and it can interfere with cellular function and therefore organ function. It can also be associated with insulin resistance.
Women lose muscle function earlier but in males it happens with a steeper decline
Fact
What effect does ageing have on the VO2max of an endurance vs sedentary individual?
On an endurance trained individual, the decline is much steeper and there’s a bigger change. However, they remain with a VO2 max higher than those sedentary so still beneficial.
At what rate does power decline with ageing?
6% p/yr, much more rapidly than strength, muscle mass etc.
Unclear whether decreases in muscle = decrease in PA, or the opposite. However with ageing, those meeting PA guidelines decreases, especially in women.
Fact
Which fibre type sees a greater decline with age?
Type 2 fibres
Why does muscle strength decline with age?
Morphological changes (decreased fibre size and number), Neural changes (denervation), Decrease in muscle mass
What changes to body composition can be seen with age?
Almost 50% decrease in muscle and an increase in fat and non muscle FFM
What is Sarcopenia? And what is it related to?
Age related involuntary loss of skeletal muscle mass and function - muscle strength and/or physical performance.
It’s directly related to reduction in mobility/function, disability and frailty, onset of chronic conditions
What are the mechanisms for sarcopenia?
Disuse - physical inactivity, immobility, zero gravity
Cachexia - weakness and wasting due to chronic illness
Endocrine changes
Inadequate nutrition / malabsorption
Age related - sex hormones, apoptosis, mitochondrial dysfunction
Anabolic resistance (reduced stim of muscle PS)
How do you assess sarcopenia?
Assess muscle mass - anthropometry, BIA, MRI
Physical performance - get up and go test, stair climb power test, usual gait speed, short physical performance battery
Strength assessment - hand grip, peak expiratory flow, knee flexion/extension
How could you optimise muscle protein synthesis?
Maximise anabolic potency and enhance anabolic sensitivity
How could you maximise anabolic potency?
Increasing daily protein intake or meal by meal protein intake
How could you enhance anabolic sensitivity?
Doing exercise prior to eating and co-ingesting other nutrients such as Leucine and Creatine.
What’s the recommended protein intake for older adults?
1-1.2 g/kg BM
Why is it recommended that older adults increase their protein?
To optimise MPS and therefore maintain their muscle mass to prevent common problems such as frailty, falls etc
What is anabolic resistance and what does it mean for older adults?
Reduced stimulation of muscle protein synthesis.
It means older adults require more EAA to stimulate PS than younger adults, so they need to consume more protein to see the same effect.
Protein and resistance training increases muscle mass in young and old adults. Combine diet with PA! This is to slow sarcopenia and maintain healthy muscle mass, not to get big. This comes with economic, social and health benefits.
Fact
What are some of the potential barriers around increasing protein intake in elderly?
Protein is very filling and they have a reduced appetite.
Low muscle strength is associated with higher risk of mobility limitations
Fact
Smaller mid-thigh muscle area and greater fat infiltration in the muscle is associated with poorer lower extremity performance
Fact
Why is lower limb muscle power important?
Correcting a displacement or movement error to prevent tripping/falling and reducing the severity of the falls effect.