为什么你总是感到很累

You skip exercise when you're tired
累的时候你就不锻炼了

Skipping your workout to save energy actually works against you. In a University of Georgia study, sedentary but otherwise healthy adults who began exercising lightly three days a week for as little as 20 minutes at a time reported feeling less fatigued and more energized after six weeks. Regular exercise boosts strength and endurance, helps make your cardiovascular system run more efficiently, and delivers oxygen and nutrients to your tissues. So next time you're tempted to crash on the couch, at least go for a brisk walk-you won't regret it.
实际上，为了节省能量而不去锻炼会给您带来不利影响。在格鲁吉亚大学的一项研究中，静坐但健康的成年人他们每周会花3天的时间轻度锻炼，每次至少锻炼20分钟，报道称6周后他们的疲劳感降低，同时更加充满活力。经常运动会加强力量和耐力、有助于心血管系统更有效地运作、并将氧气和营养物输送至人体组织。所以下一次你想躺在沙发上的时候，至少也得去散个步吧--你不会后悔的。

You don't drink enough water
喝的水不够多

Being even slightly dehydrated-as little as 2% of normal fluid loss-takes a toll on energy levels, says Amy Goodson, RD, a dietitian for Texas Health Ben Hogan Sports Medicine. Dehydration causes a reduction in blood volume, explains Goodson, which makes the blood thicker. This requires your heart to pump less efficiently, reducing the speed at which oxygen and nutrients reach your muscles and organs. To calculate your normal fluid needs, take your weight in pounds, divide in half and drink that number of ounces of fluid a day, Goodson recommends.
德克萨斯州Health Ben Hogan Sports Medicine的营养学家艾米·古德森注册营养师说道：即使只是轻度脱水--只有2%的正常液体流失--也会对能量水平造成影响。脱水会导致血量减少，使血液变厚，古德森解释道。从而使心脏跳动频率降低、降低氧气和营养物传至肌肉和器官的速度。想计算自己正常需要多少流体？用体重（磅）除以2，然后得到的数字就是你每天应喝的流体量（盎司），古德森建议。

You're not consuming enough iron
铁元素摄入不足

An iron deficiency can leave you feeling sluggish, irritable, weak, and unable to focus. "It makes you tired because less oxygen travels to the muscles and cells," says Goodson. Boost your iron intake to reduce your risk of anemia: load up on lean beef, kidney beans, tofu, eggs (including the yolk), dark green leafy vegetables, nuts, and peanut butter, and pair them with foods high in vitamin C (vitamin C improves iron absorption when eaten together), suggests Goodson. Note: an iron deficiency may be due to an underlying health problem, so if you're experiencing these symptoms of iron deficiency, you should visit your doc.
缺铁会让你感觉迟钝、易怒、虚弱、无法集中注意力。"因为进入肌肉和细胞的氧气量变少，所以你会感到很累，"古德森说道。增加铁元素摄入量、降低贫血的风险吧：多吃瘦牛肉、芸豆、豆腐、鸡蛋（包括蛋黄）、深色绿叶蔬菜、坚果和花生酱，并且与维C含量高的食物搭配食用（一起摄入时，维C能促进铁的吸收），古德森建议道。注意：缺铁可能是由于潜在的健康问题所致，所以如果你有缺铁的症状，那最好还是去看医生。

You're a perfectionist
你是位完美主义者

Striving to be perfect-which, let's face it, is impossible-makes you work much harder and longer than necessary, says Irene S. Levine, PhD, professor of psychiatry at the New York University School of Medicine.
力争完美--但面对现实吧，这是不可能的--只会让你的工作变得更难、更久，而这是完全没有必要的，纽约大学医学院精神病学教授Irene S. Levine博士说道。