Wednesday, March 26, 2008
yog is the onlything i find
has been boring for me, how hard i try......have always been a sports maniac without the touch of maradona or lee..but the only source of enjoyment and happiness...........
time is not the same now,who comes at the frontdoor now to call to the field...not even the old chaps who wud play together till we cud hardly see the ball. big or small..till we cud see....
then this routine of mine is soo irritating that i find no place other than this to express my anxiety..finally reluctantly i must say there are other things to focus and this one thing has been a big health trick for a solitary game lover..hehe i can put myself anywhere i like..
i've been practising yog for many years , i forgot how many but not less than ten. thanks to dad.i'll tell more abt yog..............
Saturday, September 29, 2007
BIOCHEMISTRY OF PHYSICAL EXERCISE
INTRODUCTION
Physical exercise is the performance of some activity to develop or maintain physical fitness and overall health.
Benefits: Frequent and regular physical exercise is an important component in the prevention of some of the diseases such as : heart disease, cardiovascular disease, Type 2 diabetes, obesity etc.
Benefits of Exercise
Brain function : In the long term, exercise is beneficial to the brain by:
increasing the blood and oxygen flow to the brain.
increasing growth factors that help create new nerve cells.
increasing chemicals in the brain that help cognition.
Breathing : Exercise helps the body to increase its maximum lung capacity, cardiac efficiency, muscular efficiency for blood flow and oxygen uptake
Types of Exercise
Flexibility exercises such as stretching improves the range of motion of muscles and joints
Aerobic exercises such as cycling, walking and running focus on increasing cardiovascular endurance.
Anaerobic exercises such as weight training, functional training or sprinting increases short-term muscle strength
Common Myth about Exercise
Weightlifting makes you short or stops growth. One caveat is that heavy weight training in adolescents can damage the epiphyseal plate of long bones.
Exercise and training of a particular body part will preferentially shed the fat on that part; for example, that doing sit-ups is the most direct way to reduce subcutaneous belly fat. This is false: one cannot reduce fat from one area of the body to the exclusion of others.
Excessive Exercise can cause immediate death. This may be due to Water intoxication, Rhabdomyolysis. Other common dangers may occur from extreme overheating or aggravation of a physical defect, such as a thrombosis or aneurism.
Excessive Exercise
Exercise is a stressor and the stresses of exercise have a catabolic effect on the body.
Contractile proteins within muscles are consumed for energy, carbohydrates and fats are similarly consumed and connective tissues are stressed and can form micro-tears.
Strenuous exercise leads to formation of reactive oxygen species and compromised antioxidant defense system. Increased electron flux through the rapidly respiring mitochondria in the active muscle may lead to an enhancement of electron leakage and consequent reactive oxygen species (ROS) production.
Proper rest and recovery are also as important to health as exercise, otherwise the body exists in a permanently injured state and will not improve or adapt adequately to the exercise.
Biochemistry of physical exercise
Two commonly applied parameters that relate nutrition with physical performance at cellular level are RQ (respiratory quotient) and VO2 max (maximal O2 consumption)
RQ= CO2/O2
VO2 max is the workload that places the highest possible demand on the working muscle and it is used to monitor intensity of exercise.
Isotope infusion can quantify the contribution of major energy substrates, plasma glucose and fatty acids and muscles tri acyl glycerols, and glycogen to energy expenditure during exercise.
Strenous exercise is associated with metabolic acidosis resulting from the production of lactic acid.
Regular low-intensity exercise influences the fatty acid composition of the phospholipids in skeletal muscle, which may contribute to changes of the skeletal muscle membrane fluidity and influence the peripheral insulin sensitivity.
Sources of Energy during Exercise
Four major sources of energy during exercise are as follows:
Muscle glycogen
Blood glucose
Plasma fatty acids
Intramuscular triacylglycerols.
Interactions of Energy sources during exercise
Energy sources during exercise vary with the duration and intensity.
Three energy systems that supply ATP during different forms of exercise.
ATP-CP SYSTEM : first to contribute
LACTIC ACID SYSTEM: second to contribute
AEROBIC SYSTEM : steady and therefore last to contribute
Energy source varies according to intensity of exercise.
All the energy for low intensity levels of exercise (25%-30% Vo2 max) is derived from plasma fatty acid oxidation.
During moderately intense exercise (65% Vo2 max) total fat oxidation increases despite reduced rate of mobilization of adipose fatty acids . Energy supplied by muscle triacylglycerol.
Within the exertion range of (60%-75% Vo2 max) fat cannot be oxidized at a high rate. Nearly half of the energy is furnished by carbohydrate oxidation.
In increased exercise intensity (65%-85% V02 max) return of adipocyte fatty acids into the plasma is reduced. This occurs despite high rate of lipolysis.
The decreased replacement of plasma fatty acids from adipocyte fat stores at high level of exercise is due to insufficient blood flow and albumin delivery of fatty acids from adipose tissue into the systemic circulation.
Fatty acids become trapped in adipose tissue and accumulate during high levels of exercise.
At higher exercise intensity (85% Vo2 max) relative contribution of carbohydrates to total metabolism increases sharply. Blood glucose derived from glycogenolysis of hepatic glycogen stores and muscle glycogen become the sole suppliers of energy.
Glucose uptake by working muscle may increase to 20-fold or more above resting levels. This is accompanied by metabolic acidosis caused by lactic acid formation in situations of oxygen debt.
The essentiality of carbohydrate as an energy substrate at moderate to high levels of exercise is due to limited ability of muscle to oxidize fat.
Muscle fatigue occurs with muscle glycogen depletion and hypoglycemia. It is prevented by reducing the workload to lowest intensity that matches the ability to oxidize fat effectively (30% Vo2 max).
Even if plasma fatty acid concentrations are high ,carbohydrate depletion fatigue remains a factor, indicating that muscle has limited ability to oxidize fatty acids.
Oxidation of fatty acids is limited by enzyme carnitine acyltransferase(CAT).CAT is inhibited by malonyl CoA. When availability of carbohydrate to the muscle is high fatty acid oxidation is reduced by inhibition of CAT by glucose derived malonyl CoA.
BENEFITS OF ENDURACE TRAINING
Endurance training (low intensity long duration exercises)increases an athletes ability to perform more aerobically at the same absolute exercise intensity as the lesser trained.
This is presumed due to an increased mitochondrial volume density in trained muscle with an increase in cardiovascular capacity.
Experiment : Effects of Exercise on Mitochondrial density
8 Participants were asked to complete a minimum of 4 and a maximum of 6 exercise sessions weekly. None of the volunteers had type 2 diabetes, coronary heart disease, peripheral vascular disease, untreated hypertension. (University of Pittsburgh Institutional Review Board.)
Exercise was performed mostly using treadmills, stationary bicycles or outdoor walking. Exercise was individually prescribed based on time and intensity, and was progressive.
For the first 4 weeks, they exercised for 30 minutes at a heart rate corresponding to 50–60% of maximal aerobic capacity (VO2max).
For the next 4 weeks, they increased exercise time to 40 minutes at the same intensity
And for the last 4 weeks they increased the intensity to ~70% of VO2max for at least 40 minutes per session.
RESULT
Examination of the effects of Exercise on skeletal muscle mitochondria in older (age=67.3±0.6 yr) men (n=5) and women (n=3) showed increase in
– cardiolipin, creatine kinase activity (CK))
– the total mitochondrial DNA
– Succinate oxidase activity,
– complexes 2–4 of the electron transport chain (ETC) and NADH oxidase activity, representing total ETC activity.
This improvement was more pronounced in Sub-Sarcolemma(SS) compared to IntraMyocellular Fibril(IMF) mitochondria.
Conclusion: Exercise enhances mitochondrial ETC activity in older human skeletal muscle which is likely related to the concomitant increases in mitochondrial biogenesis .
MITOCHONDRIAL CONTENT
Skeletal muscle mitochondria DNA (mtDNA) content was determined in biopsy samples before and after the intervention. At baseline, muscle mtDNA was lower in these elderly men and women in comparison to younger adults.
Cardiolipin (phospholipid specific to mitochondria), was quantified in each mitochondria sub-fraction of previously frozen skeletal muscle biopsies by HPLC analysis of a fluorescence-labeled derivative of cardiolipin (2-[naphthyl-1′-acetyl]-cardiolipin dimethyl ester). Cardiolipin content was normalized to the amount of CK activity as the amount of active skeletal muscle.
Impaired oxidative phosphorylation by skeletal muscle mitochondria have been postulated to contribute to age-associated insulin resistance and fat accumulation within skeletal muscle.
This impaired mitochondrial functional capacity in aging has been attributed to a reduced mitochondrial content, as reflected by lower mtDNA content.
In response to training, there was a robust improvement in the SS fraction, but there was also a substantial improvement in the intra- myocellularfibrillar (IMF2) fraction, the subpopulation of mitochondria that most directly provide energy for contracting muscle.
Biochemical benefits of exercise range from production of opioids like endorphin which leads to sensation of euphoria after intense exercise.
Aerobic exercise increases performance level of athletes coping them to endure high intensity exercise by elevating their skeletal muscle, mitochondrial density.
Intense intermittent exercise leads to capillarization and increased cardiovascular efficiency.
Rapid strenuous exercise without proper rest and nutrition must be avoided to prevent production of ROS.
ACKNOWLEDGEMENTS
Saurab Shah
Hemant Raj Joshi
Anil Chongwang
Vijayendra Agrawal
Basanta Gyawali
Physical exercise is the performance of some activity to develop or maintain physical fitness and overall health.
Benefits: Frequent and regular physical exercise is an important component in the prevention of some of the diseases such as : heart disease, cardiovascular disease, Type 2 diabetes, obesity etc.
Benefits of Exercise
Brain function : In the long term, exercise is beneficial to the brain by:
increasing the blood and oxygen flow to the brain.
increasing growth factors that help create new nerve cells.
increasing chemicals in the brain that help cognition.
Breathing : Exercise helps the body to increase its maximum lung capacity, cardiac efficiency, muscular efficiency for blood flow and oxygen uptake
Types of Exercise
Flexibility exercises such as stretching improves the range of motion of muscles and joints
Aerobic exercises such as cycling, walking and running focus on increasing cardiovascular endurance.
Anaerobic exercises such as weight training, functional training or sprinting increases short-term muscle strength
Common Myth about Exercise
Weightlifting makes you short or stops growth. One caveat is that heavy weight training in adolescents can damage the epiphyseal plate of long bones.
Exercise and training of a particular body part will preferentially shed the fat on that part; for example, that doing sit-ups is the most direct way to reduce subcutaneous belly fat. This is false: one cannot reduce fat from one area of the body to the exclusion of others.
Excessive Exercise can cause immediate death. This may be due to Water intoxication, Rhabdomyolysis. Other common dangers may occur from extreme overheating or aggravation of a physical defect, such as a thrombosis or aneurism.
Excessive Exercise
Exercise is a stressor and the stresses of exercise have a catabolic effect on the body.
Contractile proteins within muscles are consumed for energy, carbohydrates and fats are similarly consumed and connective tissues are stressed and can form micro-tears.
Strenuous exercise leads to formation of reactive oxygen species and compromised antioxidant defense system. Increased electron flux through the rapidly respiring mitochondria in the active muscle may lead to an enhancement of electron leakage and consequent reactive oxygen species (ROS) production.
Proper rest and recovery are also as important to health as exercise, otherwise the body exists in a permanently injured state and will not improve or adapt adequately to the exercise.
Biochemistry of physical exercise
Two commonly applied parameters that relate nutrition with physical performance at cellular level are RQ (respiratory quotient) and VO2 max (maximal O2 consumption)
RQ= CO2/O2
VO2 max is the workload that places the highest possible demand on the working muscle and it is used to monitor intensity of exercise.
Isotope infusion can quantify the contribution of major energy substrates, plasma glucose and fatty acids and muscles tri acyl glycerols, and glycogen to energy expenditure during exercise.
Strenous exercise is associated with metabolic acidosis resulting from the production of lactic acid.
Regular low-intensity exercise influences the fatty acid composition of the phospholipids in skeletal muscle, which may contribute to changes of the skeletal muscle membrane fluidity and influence the peripheral insulin sensitivity.
Sources of Energy during Exercise
Four major sources of energy during exercise are as follows:
Muscle glycogen
Blood glucose
Plasma fatty acids
Intramuscular triacylglycerols.
Interactions of Energy sources during exercise
Energy sources during exercise vary with the duration and intensity.
Three energy systems that supply ATP during different forms of exercise.
ATP-CP SYSTEM : first to contribute
LACTIC ACID SYSTEM: second to contribute
AEROBIC SYSTEM : steady and therefore last to contribute
Energy source varies according to intensity of exercise.
All the energy for low intensity levels of exercise (25%-30% Vo2 max) is derived from plasma fatty acid oxidation.
During moderately intense exercise (65% Vo2 max) total fat oxidation increases despite reduced rate of mobilization of adipose fatty acids . Energy supplied by muscle triacylglycerol.
Within the exertion range of (60%-75% Vo2 max) fat cannot be oxidized at a high rate. Nearly half of the energy is furnished by carbohydrate oxidation.
In increased exercise intensity (65%-85% V02 max) return of adipocyte fatty acids into the plasma is reduced. This occurs despite high rate of lipolysis.
The decreased replacement of plasma fatty acids from adipocyte fat stores at high level of exercise is due to insufficient blood flow and albumin delivery of fatty acids from adipose tissue into the systemic circulation.
Fatty acids become trapped in adipose tissue and accumulate during high levels of exercise.
At higher exercise intensity (85% Vo2 max) relative contribution of carbohydrates to total metabolism increases sharply. Blood glucose derived from glycogenolysis of hepatic glycogen stores and muscle glycogen become the sole suppliers of energy.
Glucose uptake by working muscle may increase to 20-fold or more above resting levels. This is accompanied by metabolic acidosis caused by lactic acid formation in situations of oxygen debt.
The essentiality of carbohydrate as an energy substrate at moderate to high levels of exercise is due to limited ability of muscle to oxidize fat.
Muscle fatigue occurs with muscle glycogen depletion and hypoglycemia. It is prevented by reducing the workload to lowest intensity that matches the ability to oxidize fat effectively (30% Vo2 max).
Even if plasma fatty acid concentrations are high ,carbohydrate depletion fatigue remains a factor, indicating that muscle has limited ability to oxidize fatty acids.
Oxidation of fatty acids is limited by enzyme carnitine acyltransferase(CAT).CAT is inhibited by malonyl CoA. When availability of carbohydrate to the muscle is high fatty acid oxidation is reduced by inhibition of CAT by glucose derived malonyl CoA.
BENEFITS OF ENDURACE TRAINING
Endurance training (low intensity long duration exercises)increases an athletes ability to perform more aerobically at the same absolute exercise intensity as the lesser trained.
This is presumed due to an increased mitochondrial volume density in trained muscle with an increase in cardiovascular capacity.
Experiment : Effects of Exercise on Mitochondrial density
8 Participants were asked to complete a minimum of 4 and a maximum of 6 exercise sessions weekly. None of the volunteers had type 2 diabetes, coronary heart disease, peripheral vascular disease, untreated hypertension. (University of Pittsburgh Institutional Review Board.)
Exercise was performed mostly using treadmills, stationary bicycles or outdoor walking. Exercise was individually prescribed based on time and intensity, and was progressive.
For the first 4 weeks, they exercised for 30 minutes at a heart rate corresponding to 50–60% of maximal aerobic capacity (VO2max).
For the next 4 weeks, they increased exercise time to 40 minutes at the same intensity
And for the last 4 weeks they increased the intensity to ~70% of VO2max for at least 40 minutes per session.
RESULT
Examination of the effects of Exercise on skeletal muscle mitochondria in older (age=67.3±0.6 yr) men (n=5) and women (n=3) showed increase in
– cardiolipin, creatine kinase activity (CK))
– the total mitochondrial DNA
– Succinate oxidase activity,
– complexes 2–4 of the electron transport chain (ETC) and NADH oxidase activity, representing total ETC activity.
This improvement was more pronounced in Sub-Sarcolemma(SS) compared to IntraMyocellular Fibril(IMF) mitochondria.
Conclusion: Exercise enhances mitochondrial ETC activity in older human skeletal muscle which is likely related to the concomitant increases in mitochondrial biogenesis .
MITOCHONDRIAL CONTENT
Skeletal muscle mitochondria DNA (mtDNA) content was determined in biopsy samples before and after the intervention. At baseline, muscle mtDNA was lower in these elderly men and women in comparison to younger adults.
Cardiolipin (phospholipid specific to mitochondria), was quantified in each mitochondria sub-fraction of previously frozen skeletal muscle biopsies by HPLC analysis of a fluorescence-labeled derivative of cardiolipin (2-[naphthyl-1′-acetyl]-cardiolipin dimethyl ester). Cardiolipin content was normalized to the amount of CK activity as the amount of active skeletal muscle.
Impaired oxidative phosphorylation by skeletal muscle mitochondria have been postulated to contribute to age-associated insulin resistance and fat accumulation within skeletal muscle.
This impaired mitochondrial functional capacity in aging has been attributed to a reduced mitochondrial content, as reflected by lower mtDNA content.
In response to training, there was a robust improvement in the SS fraction, but there was also a substantial improvement in the intra- myocellularfibrillar (IMF2) fraction, the subpopulation of mitochondria that most directly provide energy for contracting muscle.
Biochemical benefits of exercise range from production of opioids like endorphin which leads to sensation of euphoria after intense exercise.
Aerobic exercise increases performance level of athletes coping them to endure high intensity exercise by elevating their skeletal muscle, mitochondrial density.
Intense intermittent exercise leads to capillarization and increased cardiovascular efficiency.
Rapid strenuous exercise without proper rest and nutrition must be avoided to prevent production of ROS.
ACKNOWLEDGEMENTS
Saurab Shah
Hemant Raj Joshi
Anil Chongwang
Vijayendra Agrawal
Basanta Gyawali
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