Hiking is an outdoor activity which consists of walking in natural environments, often in mountainous or other scenic terrain. People often hike on hiking trails. It is such a popular activity that there are numerous hiking organizations worldwide. The health benefits of different types of hiking have been confirmed in studies. Some of the health benefits of hiking include, but are not limited to, losing excess weight, decreasing hypertension, and improving mental health. The word hiking is understood in all English-speaking countries, but there are differences in usage.

Related Terms
In the United States and United Kingdomhiking refers to walking outdoors on a trail for recreational purposes. A day hikerefers to a hike that can be completed in a single day - not requiring an overnight camp. Multi-day hikes with camping is referred to as backpacking. In the United Kingdom hiking is usually called rambling, which resulted in the hiking organization namedRamblersBushwhacking specifically refers to difficult walking through dense forest, undergrowth, or bushes, where forward progress requires pushing vegetation aside. In extreme cases of bushwhacking where the vegetation is so dense that human passage is impeded, a machete is used to clear a pathway. Australians use the term bushwalking for both on- and off-trail hiking. New Zealanders use tramping (particularly for overnight and longer trips), walking or bushwalking. Multi-day hiking in the mountainous regions of IndiaPakistanNepalNorth AmericaSouth America, and in the highlands of East Africa is also calledtrekking. Hiking a long-distance trail from end-to-end is also referred to as trekking and as thru-hiking in some places. Examples of long-distance trails include the Appalachian Trail (AT) and Long Trail (LT).
In Czechia and Slovakiatramping (Czechtramping, tremping, word borrowed from English) is a combined culture of hiking,backpackingscoutingwoodcraftmusic, with the characteristic flavor of American culture, especially Wild West.

The equipment required for hiking depends on the length of the hike, and according to the source. Hikers generally carry water, food, and a map in a backpack. Hikers often wear hiking boots to protect their feet from rough terrain. Some outdoor organizations, such as The Mountaineers strongly advocate a list of equipment for hiking, such as the Ten Essentials. This list includes items such as a compass, sunglasses, sunscreen, clothes, flashlightfirst aid kitfire starter, and knife. Other sources suggest additional items such as insect repellent and an emergency blanket. Nowadays a GPS navigation device is a great help especially in weather conditions with low visibility or when hiking in unknown territories.
Proponents of ultralight backpacking claim that long lists of required items for multi-day hikes increases pack weight, and hence fatigue and chance of injury. Instead, they recommend a goal of reducing pack weight in order to hike long distances easier. Even the use of hiking boots on long-distances hikes is controversial among ultralight hikers, due to their weight.

Environmental Impact
Hikers often seek beautiful natural environments in which to hike. These environments are often fragile: hikers may accidentally destroy the environment that they enjoy. While the action of an individual may not strongly affect the environment, the mass effect of a large number of hikers can degrade the environment. For example, gathering wood in an alpine area to start a fire may be harmless if done once (except for wildfire risk). Years of gathering wood, however, can strip an alpine area of valuable nutrients. Generally, protected areas such as parks have regulations in place to protect the environment. If hikers follow such regulations, their impact can be minimized. Such regulations include forbidding wood fires, restricting camping to established camp sites, disposing or packing out faecal matter, imposing a quota on the number of hikers per mile.
Many hikers espouse the philosophy of Leave No Trace: hiking in a way such that future hikers cannot detect the presence of previous hikers. Practitioners of this philosophy obey its strictures, even in the absence of area regulations. Followers of this practice follow strict practices on dealing with food waste, food packaging, and alterations to the surrounding environment.
Human waste is often a major source of environmental impact from hiking. These wastes can contaminate the watershed and make other hikers ill.Bacterial contamination can be avoided by digging 'catholes' 10 to 25 cm (4 to 10 inches) deep, depending on local soil composition and covering after use. If these catholes are dug at least 60 m (200 feet) away from water sources and trails, the risk of contamination is minimized.
Sometimes hikers enjoy viewing rare or endangered species. However, some species (such as martens or bighorn sheep) are very sensitive to the presence of humans, especially around mating season. To prevent adverse impact, hikers should learn the habits and habitats of endangered species.
There is one situation where an individual hiker can make a large impact on an ecosystem: inadvertently starting a wildfire. For example, in 2005, aCzech backpacker burned 7% of Torres del Paine National Park in Chile by knocking over an illegal gas portable stove. Obeying area regulations and setting up cooking devices on designated areas (or if necessary on bare ground) will reduce the risk of wildfire.

Etiquette Of Hiking
Because hiking is a recreational experience, hikers expect it to be pleasant. Sometimes hikers can interfere with each others' enjoyment, or that of other users of the land. Hiking etiquette has developed to minimize such interference. For example:
  • When two groups of hikers meet on a steep trail, there may be contention for use of the trail. To avoid conflict, a custom has developed in some areas whereby the group moving uphill has the right-of-way.
  • Being forced to hike much faster or slower than one's natural pace can be annoying, and difficult to maintain consistently. More seriously, walking unnaturally fast dramatically increases fatigue and exhaustion, and may cause injury. If a group splits between fast and slow hikers, the slow hikers may be left behind or become lost. A common custom is to encourage the slowest hiker to hike in the lead and have everyone match that speed. Another custom is to have experienced hiker(s) sweep up the rear on a rota, to ensure that everyone in the group is safe and nobody straggles.
  • Hikers generally enjoy the peace of their natural surroundings. Loud sounds such as shouting or loud conversation, or the use of mobile phones, disrupt this enjoyment.

Hiking may produce threats to personal safety. These threats can be dangerous circumstances while hiking and/or specific accidents or ailments. Diarrhea has been found to be one of the most common illness afflicting long-distance hikers in the United States. 
Noxious plants that cause rashes can be particularly bothersome to hikers. Such plants include poison oakpoison ivypoison sumac, and stinging nettles.
Dangerous hiking circumstances include losing the way, inclement weather, hazardous terrain, or exacerbation of pre-existing medical conditions. Specific accidents include metabolic imbalances (such asdehydration or hypothermia), topical injuries (such as frostbite or sunburn), attacks by animals, or internal injuries (such as ankle sprain).
Attacks by humans are also a reality. There are organizations that promote prevention, self defense and escape. Cell phone and GPS devices are used by some organizations.
In various countries, borders may be poorly marked. It is good practice to know where international borders are. For example, in 2009, Iran seized three American hikers for crossing over the Iran-Iraq border while hiking. Many nations, such as Finland, have specific rules governing hiking across borders.