A cross-country skier in full flight can use up almost 1000 calories per hour. In terms of the effort required, the skills levels and the duration of some competitive races, there is little to compare with an international cross-country skiing event, and when combined with rifle shooting, as in the sport of biathlon, the demands become even more complex. But the sport does not have to be undertaken at such demanding levels. For people young and old, skiing through the snowy countryside at a relaxed pace provides beneficial levels of exercise, whilst at the same time introducing the participants to the spectacular scenery of the great outdoors.

The history of cross-country skiing is a long one, even having been recorded as a method of transport in prehistoric times. In Scandinavian countries they have documented use of the transport method as far back as the early 13th Century when it was used to track and hunt animals.

For the armed services, cross-country skiing is a fundamental part of basic training for any group that may have to operate in snow-covered terrain. As well as being a basic transport and survival technique it provides the environment for teamwork and physical exercise too. The sport is used so often in the disciplines of the armed services in so many countries, that the top athletes often hail from those groups. Another reason is that the training needs to be of such duration and usually in specific locations, that only the armed services have access to the facilities required to train and compete at the highest level.

Location is an important consideration for cross-country skiing, but the perceived requirement for picturesque, mountainous and wooded areas covered in fresh snow may be slightly misleading. Obviously in an ideal world anyone would choose to ski in locations that provide those kinds of conditions, but if they are not available, people can still ski. Unlike downhill skiing, cross-country skiing does not require any gradients, removing the need for it to be based in mountainous or hilly areas, nor does it need any infrastructure like lift systems, which again open up many more areas. For geographies without the benefit of regular snow, a variety of skiing called roller skiing is also an option. Here participants used skis fitted with wheels and are able to travel across grass and tarmac surfaces. Popular venues in the UK are around rowing lakes and in city parks where the terrain is often completely level and traffic free. As we will see later, indoor cross-country skiing is now also becoming a possibility.

Alongside marathon running, some of the world's biggest mass-participation sports events are cross-country skiing races. In Norway, the annual Birkebeinerrennet, a popular 54 kilometer race, nearly always attracts a full field of 12,000 participants. The race has been held for the past sixty years and the rules require athletes to carry a back pack weighing 3.5 kg, simulating the weight of the small child who was heir to the Norwegian throne and had to be rescued in similar manner back in the 13th Century. The speed of the competitors has slowly increased over the years as technique and equipment has improved and in 2008 the winner completed the course in less than two and half hours. In Switzerland the 42km Engadin Ski Marathon also attracts 12,000 athletes, and Sweden's equivalent race, the 90km Vasaloppet, held in the north west of the country during the first week of March, manages to attract a field of 15,000 skiers.

A new form of cross-country skiing is gaining in popularity with those less physically able. Skijoring is a derivative where the skier is assisted in forward motion by being pulled along behind a snowmobile or even by a small team of dogs.

Cross country skiing is even moving indoors now, with the development of technology that allows snow to be generated and maintained at temperatures low enough for it not to melt. In the UK, several snow centres have been built over recent years and, although they are primarily designed for downhill activities such as indoor skiing or indoor snowboarding, they can also be used as training venues for certain aspects of cross-country skiing. At The Snow Centre in Hemel Hempstead, one of the slopes is dedicated to cross-country ski training at certain times, when skiers can use the facilities to fine tune their climbing and descending technique.

Primarily in Finland, but also in Sweden and Germany, facilities called ski tunnels have also been built. In a similar way, these tunnels allow cross-country skiing on snow to be enjoyed all year round. In Germany, the DKB Skisporthalle in Oberdorf provides a track loop of almost 2 kilometers in length. In Torsby, Sweden the ski tunnel is 1.3 kilometers in length and claims to be the longest in the world. The world's first ski tunnel was built at the Vuokatti Sports Institute, Finland in 1998.

With increased access to facilities and suitable locations, cross-country skiing may be set to increase in popularity as more people become aware of this enjoyable sport and its health benefits.