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.
There are 57,506,000 square miles of land surfaces in the world, including much that is uninhabitable by humans (Antarctica, arctic climes, swamps, mountains, and deserts).  â¦  The metric equivalent is 148,940,000 km2 and this represents 29.2% of the Earth's total surface area.