Essay about CHapter 10 Physical Activity

Submitted By Drishti-Dhawan
Words: 1412
Pages: 6

Chapter 10 Physical Activity

More Canadians are getting unfit
Endurance 4-7 days a week
Flexibility 4-7 days a week
Strength 2-4 days a week
60 minutes recommended each day
Fitness Essentials
Variety of flexibility, muscle strength, muscle endurance, and cardio endurance
Muscles respond to an overload of physical activity by gaining strength and size, a response called hypertrophy
Autotrophy is the opposite- a decrease in size from disuse
Muscles adapt to activities they are called upon to perform repeatedly. For example the muscle cells of a swimmer develop stocks of myoglobin, the muscles oxygen handling protein, which are needed to sustain long cardio whereas a body builder wouldn’t have this
Weight Training
Builds lean body mass
Promoting strong muscles in the back and abs, it improves posture and reduces the risk of back injury
Maximizes bone mass
Improves health of the heart. Body delivers oxygen more efficiently and blood volume increases (cardiac output)
Stoke volume- the amount of oxygenated blood ejected from the heart toward body tissues. This increases with cardio
Blood pressure normal
Raise HDL
Body’s Use of Fuels
Mostly glucose, fatty acids, and to a small extent, animo acids
In early minutes of an activity, muscle glycogen provides the majority of energy the muscles use. As time progresses, the liver and fat cells liberate their store energy (glucose and fatty acids).
Liver and muscles store glucose as glycogen. Muscles hoard their glycogen stores but the liver shares it with other body tissues
Muscle hoarding comes in handy for emergencies
The more carbs a person eats, the more glycogen muscles store, and the longer the stores will last physical activity
Total glycogen stores affect an athlete’s endurance
Activity Intensity/Glucose Use/ Glycogen Stores
Fat stores can provide energy for hours and not run out unlike glycogen. How long a person’s glycogen will last while exercising depends not only on diet but also on the intensity of the activity
Intense activity, the kind that makes it difficult “to catch your breath” uses glycogen quickly. Muscles must begin to rely more heavily on glucose, which can be partially broken down by anaerobic metabolism. Thus the muscles begin drawing more heavily on their limited glycogen supply
Aerobic, moderate physical activity uses glycogen slowly. Thus moderate aerobic activity conserves glycogen stores
During intense anaerobic activity, breakdown of glucose produces lactic acid which in excess can be converted back to glucose.
When the rate of lactic acid production exceeds the rate of clearance, intense activity can be maintained only for 1-3 minutes
During anaerobic metabolism, the body spends glucose rapidly and accumulated lactic acid.
Activity Duration
In the first ten minutes, the muscles rely on their own stores of glycogen. Within the first 20 minutes, a person uses blood glucose. 20+minutes uses more fat for fuel
Glycogen depletion generally occurs after about two hours of vigorous exercise. Physical activity can continue for a short time after only because the liver scrambles to produce glucose from available lactic acid which can only sustain activity for a brief moment

Maintaining Blood Glucose for Activity
To postpone exhaustion, endurance athletes must maintain their blood glucose concentrations. This can occur by eating a high carb diet on a daily basis, intaking glucose during the activity as fluid usually, and to eat carb foods after activity to boost the storage of glycogen
These methods trains the muscles to store as much glycogen as they can while supplying enough dietary glucose to do so from the diet
Glucose during Activity
Glucose ingested before/during exhausting endurance activities makes it way from the digestive tract to the working muscles
Only useful when exercising nonstop for 45 minutes
Carb Loading
Moderate exercise, following by eating a high carb diet, that enables muscles to temporarily store glycogen beyond their