You may feel tired and need extra rest the first few weeks after surgery.

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Afterward, you may feel lightheaded and tired.

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Let's say that you feel bad about running over a small animal late at night, while you were feeling tired at the wheel.

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"You need enough sleep to wake up and not feel tired and fatigued the next morning, " he says.

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The amount of weight you use should be challenging enough that your muscles feel tired by the end of the second set.

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When I'm really on a roll if I'm not too tired - and that does gives you kind of energy when you feel like, okay, I'm in a groove now and I'm going in the right direction.

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