An article I read states the obvious advantages of walking but still to many, perhaps less obvious gains that regular, brisk exercise of any kind can improve confidence, stamina, weight control and life expectancy and reduce stress. It can also reduce the risk of coronary heart disease, strokes, diabetes, high blood pressure, bowel cancer, and osteoporosis. Scientific studies have also shown that walking, besides its physical benefits, is also beneficial for the mind, improving memory skills, learning ability, concentration and abstract reasoning as well as lifting the spirits. Sustained walking sessions for a minimum period of thirty to sixty minutes a day, five days a week, with the correct walking posture, reduce health risks and have various overall health benefits, such as reducing the chances of cancer, type 2 diabetes heart disease anxiety and depression. Life expectancy is also increased even for individuals suffering from obesity or high blood pressure. Walking also improves bone health, especially strengthening the hip bone, and lowering the harmful (LDL) cholesterol, and raising the useful (HDL) cholesterol. Studies have found that walking may also help prevent dementia and Alzheimers's.
The US Centres for Disease Control and Prevention's fact sheet on the "Relationship of Walking to Mortality Among U.S. Adults with Diabetes" states that those with diabetes who walked for 2 or more hours a week lowered their mortality rate from all causes by 39 per cent. "Walking lengthened the life of people with diabetes regardless of age, sex, race, body mass index, length of time since diagnosis, and presence of complications or functional limitations." It has been suggested that there is a relationship between the speed of walking and health, and that the best results are obtained with a speed of more than 2.5 mph (4 km/h).
Governments now recognise the benefits of walking for mental and physical health and are actively encouraging it. This growing emphasis on walking has arisen because people walk less nowadays than previous generations. In the UK, a Department of Transport report found that between 1995 and 2005 the average number of walk trips per person per year fell by 16%, from 292 to 245. Many professionals, local authorities and the NHS are employed to halt this decline by ensuring that the built environment allows people to walk and that there are walking opportunities available to them. Professionals working to encourage walking come mainly from six sectors: health, transport, environment, schools, sport and recreation, and urban design.
One programme to encourage walking is "The Walking the Way to Health Initiative", organised by The Ramblers, which is the largest volunteer led walking scheme in the United Kingdom. Volunteers are trained to lead free Health Walks from community venues such as libraries and doctors' surgeries. The scheme has trained over 35,000 volunteers and have over 500 schemes operating across the UK, with thousands of people walking every week. A new organisation called "Walk England" launched a web site in June 2008 to provide these professionals with evidence, advice and examples of success stories of how to encourage communities to walk more. The site has a social networking aspect to allow professionals and the public to ask questions, post news and events and communicate with others in their area about walking, as well as a "walk now" option to find out what walks are available in each region. Similar organisations exist in other countries and recently a "Walking Summit" was held in the United States. This "assembled thought-leaders and influencers from business, urban planning and real estate,along with physicians and public health officials," and others, to discuss how to make American cities and communities places where "people can and want to walk".
More about the 'origin' of walking
It is theorized that "walking" among tetrapods originated underwater with air-breathing fish that could "walk" underwater, giving rise eventually to the plethora of land-dwelling life that walk on four or two limbs, while terrestrial tetrapods are believed to have a single origin, anthropods and their relatives are thought to have independently evolved walking several times, specifically in insects, myriapods, chelicerates, tardigrades, onychophorans, and crustaceans. Little skates, members of the fish community, can propel themselves by pushing off the ocean floor with their pelvic fins, using neural mechanisms which evolved as early as 420 million years ago, before vertebrates set foot on land.
Judging from footprints discovered on a former shore in Kenya, it is thought possible that ancestors of modern humans were walking in ways very similar to the present activity as many as 1.5 million years ago.
There are a huge variations of 'walking' some that are listed below are more recent leisure activities now that man has 'time on his hands' and the health benefits become more widely appreciated.
The Human Walking Cycle
Human walking is accomplished with a strategy called the double pendulum. During forward motion, the leg that leaves the ground swings forward from the hip. This sweep is the first pendulum. Then the leg strikes the ground with the heel and rolls through to the toe in a motion described as an inverted pendulum. The motion of the two legs is coordinated so that one foot or the other is always in contact with the ground. It is facinating to know that the process of walking recovers approximately sixty per cent of the energy used due to pendulum dynamics and ground reaction force.
Walking differs from a running gait in a number of ways. The most obvious is that during walking one leg always stays on the ground while the other is swinging. In running there is typically a ballistic phase where the runner is airborne with both feet in the air.
Another difference concerns the movement of the centre of mass of the body. In walking the body "vaults" over the leg on the ground, raising the centre of mass to its highest point as the leg passes the vertical, and dropping it to the lowest as the legs are spread apart. Essentially kinetic energy of forward motion is constantly being traded for a rise in potential energy. This is reversed in running where the centre of mass is at its lowest as the leg is vertical. This is because the impact of landing from the ballistic phase is absorbed by bending the leg and consequently storing energy in muscles and tendons. In running there is a conversion between kinetic, potential, and elastic energy.
There is an absolute limit on an individual's speed of walking (without special techniques such as those employed by speed walkers) due to the upwards acceleration of the centre of mass during a stride – if it's greater than the acceleration due to gravity the person will become airborne as they vault over the leg on the ground. Typically however, animals switch to a run at a lower speed than this due to energy efficiencies.
Many people enjoy walking as a recreation in the mainly urban modern world, and it is one of the best forms of excersise. For some, walking is a way to enjoy nature, the outdoors and the social interaction; and for others the physical, sporting and endurance aspect is as or more important.
There are seemingly infinite variety and terminology with walking that often depends where you are in the world. It can be hillwalking, volksmarching, Nordic walking or even, snow shoeing. Some people may prefer to walk indoors on a treadmill, and the explosion in the use of fitness watches and apps, walkers are now seen to be counting their steps, measure their distance, look at their BPM check on 'floors' climbed, altitude, resting heart rate..........etc. etc. Hiking is the usual word used in Canada, the United States and South Africa for long vigorous walks; similar walks are called tramps in New Zealand, or hill walking or just walking in Australia, the UK and in the Irish Republic. Australians also bushwalk. In English-speaking parts of North America the term walking is used for short walks, especially in towns and cities. Taking a 'hike' can mean something completely different!
In terms of the benefits to tourism the possibilities are vast and range from guided walking tours in cities, to organised hiking holidays in the Himalayas. In the UK we use the term walking tour to also refer to a multi-day walk or hike undertaken by a group or individual either guided or self-led. Well-organised systems of track and paths exist in many other European counties, as well as Canada, United States, New Zealand, and Nepal. A network of lengthy waymarked walking trails now stretch across Europe from Norway to Turkey, Portugal to Cyprus. Many thousands also walk the traditional pilgrim routes, of which the most famous is El Camino de Santiago. In the UK we are blessed with many long-distance trails that sometimes follow the ancient trading paths of our ancestors or coastal paths of hundreds of miles in length. These can be completed from say, several days with overnight camping or lodgings, to many weeks. Some choose to pick off days as and when they are able which can stretch the journey over many years!
Numerous walking festivals and other walking events take place each year in many countries. This can significantly boost local tourism with many hotels full and rebooked each year. In the UK we are particularily 'good at' walks organised as charity events, with walkers sponsored or pay to enter for a specific cause. 
These walks range in length from just a mile or even to a couple of days to cover 100 miles plus. Some examples, the MS Challenge Walk is an 80 km or 50 mile walk which raises money to fight the disease, while walkers in the Oxfam Trailwalker cover 100 km or 60 miles. British Heart Foundation is another charity that has a multitude of fund raising walks, all over the country. Just check out their website and there will be one near you!
In Britain, The Ramblers, a registered Charity, is the largest organisation that looks after the interests of walkers, with some 100,000 members. Its "Get Walking Keep Walking" initative provides free route guides, led walks throughout the year, as well as information for people new to walking. Perhaps less known is the work they do in clearing paths and installing gates to make accessibility easier for the less mobile. The Long Distance Walking Association in the UK is for the more energetic walker, and organises lengthy challenge hikes of 20 or even 50 miles (30 to 80 km) or more in a day. The LDWA's annual "Hundred" event, entailing walking 100 miles or 160 km in 48 hours, takes place each Spring Bank Holiday weekend.
This is just the 'tip of an iceburg' when it comes to explaining how walking has meant so much for so many people so I think I better stop rambling here...................