Answer to Question 1
Our bodies are simply not designed for extended periods of sitting. As we sink into inactivity, our biological processes begin to change, down to a cellular and molecular level. Researchers are only beginning to understand all of the factors at work, but studies show, for example, that blood flow becomes sluggish and is more likely to form life-threatening clots in the lungs and legs. Blood sugar levels drop. And after meals, blood sugar levels spike due to inactive skeletal muscles, which are responsible for 80 percent of glucose disposal when active. The level of triglycerides in the blood jump during inactivity, because muscles stop producing an enzyme that usually captures this type of fat from the blood in order to turn it into fuel. Even HDL cholesterol levels (the good cholesterol) drop 20 percent after as little as one hour of uninterrupted sitting. Inactivity also appears to switch on or off dozens of genes that trigger additional risk factors.
Answer to Question 2
Health-related fitness is related to the ability to perform activities of daily living without undue fatigue and is conducive to a low risk of premature hypokinetic diseases. The health-related fitness components are cardiorespiratory (aerobic) endurance, muscular strength and endurance, muscular flexibility, and body composition. Students should describe activities that are continuous and relatively long-lasting, use a majority of body muscles, and are moderate-to-vigorous in intensity. Skill-related fitness components consist of agility, balance, coordination, reaction time, speed, and power. These components are related primarily to successful sports and motor skill performance and might not be as crucial to better health.
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