Depression increases your risk of a number of diseases and other conditions by, for example, increasing levels of stress hormones such as cortisol or adrenaline. Depression can affect the immune system, making it harder for your body to fight infection. Vaccinations are even less effective in people with depression.
The total surface area of the Earth is about 7008510000000000000â 510 million km2 (197 million sq mi). Of this, 70.8%, or 7008361130000000000â 361.13 million km2 (139.43 million sq mi), is below sea level and covered by ocean water.
Where the world lives: Map shows half the planet's population lives on just 1% of its land. Land covers 196.9 million square miles of the planet, which is broken up into 196 countries that are home to 7.125 billion people. With so much land available on Earth you would think people are spread out evenly throughout the world - but a stunning new map reveals that isn't the case.