Sarcopenia Flashcards
-what % of canadians are either overweight/obese
23%
what # of mod to big exercise per day increases longevity
12 mins
why we getting getting old
- younger inv are sarcopenia
- reduction in pluripotent stem cells (decreases efficiency in generating tissue)
- Mito dysfunction
- oxidative stress + cell death
causes of aging (2)
- chronic inflammation
- increased adiposity (influences mm tissue directly)
What is sarcopenia (when does it start/ how much loss per year)
mm loss begins in 30s/40s
-loss of up to 8% per decade until age 70
-mm breakdown leads to weakness (dynapenia)
lifestyle causes of sarcopenia
- too much cardio/ not enough resistance training
- poor food choices
- mm wasting
- social changes
BMI compared to DEXA
sometimes underestimates
dx criteria categories for sarcopenia (5) and score of > what is predictive
Strength assistance walking rise from chair climb stairs falls
score >4 is predictive of sarcopenia
osteopenia sarcopenia
link bw sarcopenia and osteoperosis
-loss of type II mm fibres and process of osteoporosis occur nearly simultaneously
sarcopenia has been shown to increase risk of falls by how much
1.5-3x
5 main theroies of mito aging
- free radical theory of aging
- superoxide theory
- oxidative stress theory
- mito free radical theory
- free radical theory of frailty
exercise and ROS
mm contraction can activate redox-sensitive signal transduction pathway to stim expression of certain gene products that function to restore homeostatsis
-if ppl are not active , they will not up regulate these genes to keep ROS at healthy levels
what are the 4 ROS sensitive pathways
- Nuclear factor kappa (NF)
- mitogen-activated protein kinase (MAPK)
- Heat shock proteins (HSP)
- peroxisome proliferator-activated receptor gamma coactivator (PGC)
changes in gene expression from exercise lead to what (4)
- antioxidant enzymes (upreg by increased secretion of ROS in controlled env-mm contraction)
- Transcription factors and cofactors required for nuclear binding
- Molecules controlling redox status
- wide range of pros that could influence metabolic status and thus ROS prod
What is mito biosynthesis reliant upon
- ability to secrete more mito is beneficial for older adult functioning
- dependent on peroxisome proliferator activated receptor gamma coactivator (PGC-1)
what are the 2 circuits to adaption to exercise
- Normal redox circuit (a-left column)
2. Impaired redox circuit (e-right column)
what occurs in the normal redox circuit
signal of increased oxidative stress causes activation of sensor
-adaptive response improves cellular function
what occurs in the normal redox circuit
signal of increased oxidative stress causes activation of sensor
-adaptive response improves cellular function
what occurs during the impaired redox cycle and why
- sedentary inv w increased ROS that is unmanaged
- with age resting levels are elevated (leads to less sensor activation)
- adaptive mechanisms are desensitized (elevated lvls of stress are not lowered and we are not allowing our bodies to functionally adapt
CRP and training effects in older women
after training had a sig decrease in CRP (training allows for hormesis and allows for antioxidants to allow the body to adapt, increased capacity to manage the inflammatory response in the body)
effects of resistance training
resistance training 2x a week reduces all cause, cancer and cardiac death
-older adults that reported guideline resistance training had 46% lower odds of all cause mortality
what are the specific stressors of aerobic ex and the adaptiveresponke
stressors- energetic and oxidative stress, misfoldings of pro
adaptive response- increase antioxidants, mito biogenesis, enhance pro folding capacity, increase myofibrillar pro synthesis
effects of resistance training
- can counteract sarcopenia and dynapenia characterized by decreased pro content and increased lipid infiltration
- low levels of mm strength are predictive of poor physical function and increased mortality
con vs eccentric training
- compared to concentric, EC causes more structural damage to the myocyte and oxidative damage to myofibril pro and enzymes
- inflammation increases blood perfusion, which increase nitric oxide
what can too much EC do
inhibit PGC1a and mito biogenesis
what doe high dietary pro do in calc restriction
in cal restriction, a higher pro consumption seems to increase lean body mass and decrease fat mass
-dietary pro sup sig increase strength, 1RM, FFM, mm size
what is hyperaminoacidemia (in young + old_
post feeding hyperaminoacidemia is a potent stim of skeletal mm protein synthesis in young adults and is blunted in older adults
what % of Americans are eating under the RDA for protein
40% of americans are eating less than .8g/kilo
what is the adequate bolus of pro to upregulat MTOR
around 30g
(need >1.2g/kilo per day spread thru 30g increments0
taking how much pro sig decreases Sarcopenia risk score
those taking in >1.2g/k have sig decreased SRS
20 vs 40g of pro post workout in older indv
sig improvements in chest press, shoulder press and leg extension strength were observed following 40g dose
how does cur cumin help mm atrophy
supreses NFkB (as NFkB usually inhibits PCG-1)
EPA and DHA effects of sarcopenia and how long does it take
-can improve mm synthesis
4 weeks- protect from disuse atrophy
plateu @ 6w- potentiation of mm pro synthesis to insulin and amino acid infusion
effects of omega 3
antiinflammatory effects (inhibits NFkB and COX2)
- amino acid transport
- pro kinase activity
- mTOR localization
- Mitochondrial function
