A study published in Blood Pressure Monitoring stated that sitting with your legs crossed can increase your blood pressure. The reason this happens is because the blood in your legs has to work against gravity to be pumped back to your heart, crossing one leg over the other increases resistance, making it even harder for the blood to circulate. This causes your body to increase your blood pressure to push the blood back to the heart. You won’t feel any immediate effects, but if you sit for long periods of time it’s important that you take note of how long you have your legs crossed for. You shouldn’t have your legs crossed for more than 15 minutes, and it’s important that you get up and walk around at least once every hour.

Crossing your legs can also lead to neck and back pain. Ideally, it’s best for our bodies to sit with our feet planted flat, hip width apart, on the floor, but it’s not easy to maintain perfect posture all day at the office. When you sit with your legs crossed your hips are in a twisted position, which can cause one of your pelvic bones to rotate. Since your pelvic bone supports your neck and spine, this can cause pressure on your lower and middle back and neck.

You also might notice that when you sit with your legs crossed for long periods of time your feet and legs get tingly or have the feeling of being asleep. This is because when one leg sits on top of the other it causes pressure on the veins and nerves in your legs and feet. It can cause numbness and/or temporary paralysis in the legs, ankles, or feet. While the feeling of discomfort may only last a minute or two, repeatedly crossing your legs until they feel numb can cause permanent nerve damage.

Take care of your spine（脊柱）

The spine stands at the center of your health, providing your body with structure and support. It also contains your spine cord, a massive collection of nerves conveying electric signals from the rest of your body to your brain【小题1】

Maintaining good posture( 姿势) is one of the most important things you can do to keep your spine healthy. Proper posture means standing or sitting while keeping your spine straight, except for its natural curves. Posture comes into play even when you are asleep. Sleeping on your side puts less stress on your spine than most other positions. 【小题2】 . Especially if you work at a desk most of the day, it's important to get up and stretch regularly.

【小题3】Stretch can help the muscles around your spine relax and allow bones to shift into better arrangement. Strength exercises like pushups(俯卧撑) can also help by strengthening the muscles around your spine. However, don’t overdo the exercise, as repeated motions can strain the muscles around your spine.

Finally, your diet affects the health of your spine because many vitamins are necessary for bones and nerves. In particular, vitamins B and D are essential to keep bones healthy, so you may want to consider taking a supplement.【小题4】, so it is also helpful to do some of the back exercise outside.

Many of the actions necessary to keep your spine healthy are identical to those used to preserve your health in other ways.【小题5】

Hearing loss is unavoidable, but listening to loud music when you’re younger can make it worse. To reduce your risk of hearing loss via loud music, learn why and how it can cause hearing loss, and just how loud is too loud.

Hearing loss occurs in four ways: conductive hearing loss, sensorineural hearing loss, mixed hearing loss and auditory neuropathy spectrum disorder. Noise-induced (噪音诱发的) hearing loss is a type of sensorineural hearing loss.

Sensorineural hearing loss occurs when your inner ear becomes damaged. In the case of noise- induced hearing loss, most of the damage affects the cells of tiny sensory hairs in your inner ear.

When those cells get damaged or die, the electrical signal that your auditory nerve sends to your brain changes.

Noise-induced hearing loss can be acute or severe, and it can be temporary or permanent. You might be familiar with acute temporary noise-induced hearing loss, even if you didn’t realize what was happening at the time.

Acute temporary noise-induced hearing loss can occur from attending a loud concert or sporting event, going to a gun range without earmuffs or being near an explosion. It can make noises sound “stuffy” or far away, especially when talking on the phone or in a crowded room. Repeated exposure to those loud situations can eventually lead to permanent hearing loss.

Noise levels from earbuds and headphones can get as loud as 139 decibels, according to the journal Noise &Health, far greater than the recommended range of everyday sound exposure, which is 60 to 85 decibels. And the average level of noise from headphones, with the volume turned all the way up, is 94 to 110 decibels. For context, 60 decibels is about the volume of an average conversation, and 130 decibels is about the noise level of a rock concert. 85 decibels is considered the maximum volume at which you can listen to sound for eight hours without damaging your hearing. So if you were to listen to music from your headphones for eight hours a day, listening at a volume louder than 85 decibels can cause permanent damage to your ears.

Unfortunately, the relationship between decibels and time isn’t linear (线性的). For every three decibels, safe exposure time gets cut in half, according to the CDC. At 88 decibels, you can only safely listen for four hours; at 91 decibels, just two hours.