[Physical activity to delay the effects of aging on mobility].
SARCOPENIA: Aging is accompanied by the progressive reduction in cardio-pulmonary capacity and muscular strength. These two phenomena are partly related to the decrease in muscle mass, or sarcopenia. CARDIO-PULMONARY CAPACITY: Measured by maximum oxygen consumption (VO2max), it demonstrates the individual's capacity for movement. It is also the principle marker of mortality due to cardiovascular events. VO2max decreases by around 0.8% each year, in close correlation with the evolution in muscle mass. These phenomena are partly related to reduced physical activity and, particularly, intense activity greater than 6 MET. Regular practice of moderately intense physical activity can maintain VO2max at a level 20 to 35% superior to that of the mean level in the same age range, and is associated with increased autonomic nervous system activity. DECREASED MUSCULAR STRENGTH: Sarcopenia and the proportional decrease in fast-twitch muscle fibers are related to a reduction in physical activity. The decrease in muscular strength is a handicapping factor and increases the risk of falls. Two sessions of training per week can increase by more than 30% the strength of the muscles concerned, by increasing the muscle volume and the maximum frequency of emission of motoneuron influx. The production of somatotropin, insulin-like growth factor-I and testosterone can also be increased. High-resistance exercises are themselves sufficient to increase bone density. In the light of these advantages, the practice of workouts in endurance and strength should be encouraged.
Service de gériatrie, Centre hospitalier Lyon-sud. lacour@univ-lyon1.fr
Jean-René
JR
Lacour
Tomasz
T
Kostka
Marc
M
Bonnefoy
D000058:Accidental Falls / Q000706:statistics & numerical data; D000203:Activities of Daily Living; D000368:Aged; D000375:Aging / Q000502:physiology*; D015519:Bone Density / Q000502:physiology; D002320:Cardiovascular Physiological Phenomena; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D013006:Growth Hormone / Q000502:physiology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000502:physiology; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000209:etiology* / Q000517:prevention & control*; D010101:Oxygen Consumption; D010807:Physical Endurance; D012143:Respiratory Physiological Phenomena; D012307:Risk Factors; D012737:Sex Factors; D013739:Testosterone / Q000502:physiology
D013739:Testosterone; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone