Sleep is crucial for good health. It helps memory and【B1】______, keeps you f

Sleep is crucial for good health. It helps memory and(26)mood, keeps you fit, strengthens your immune system, fights inflammation and keeps your heart and blood(27)vessels in tip-top shape.
    While you’re snoozing, the body repairs damaged(28)tissue, produces crucial hormones and strengthens memories—a process called consolidation, which helps you perform a new skill better after sleeping than you would if you spent an(29)equivalent amount of time awake. It’s a way for the body to(30)integrate everything that happened over the past waking day and to kind of prepare for the next day.
    Short sleepers, typically(31)defined as people who get less than six hours of sleep at night, as well as people who don’t spend enough time in the deepest stages of sleep, are at higher risk of heart attacks and strokes than those who get at least seven hours.
    It’s not clear why sleep may affect the heart, or if there is some(32)unidentified factor that affects your cardiovascular system and ability to sleep. But one nighttime problem is a known heart(33)hazard— sleep apnea(睡眠呼吸暂停). People who have this problem tend to snore and have upper airway collapse during sleep. This causes them to snort and gasp for breath, without really waking up enough to(34)be aware of it.
    If you’re not feeling rested during the day and your bed partner says you snore, you should ask your doctor about sleep apnea. There’s enough evidence out there suggesting that it is bad and people need to(35)take it seriously.