Calories burned outdoors: from hiking to ski touring

How do you actually measure whether cross-country skiing burns more calories than hiking? The answer is MET, the Metabolic Equivalent of Task. One MET equals your energy use at rest: roughly 1 kcal per kilogram of body weight per hour.

The formula is simple: kcal/h = MET × body weight (kg). If you weigh 80 kg and do a sport rated at MET 8, you burn around 640 kcal an hour.

The most important source for MET values is the 2024 Compendium of Physical Activities, the third major update since 1993. The researchers screened more than 32,000 abstracts and extracted 2,356 energy expenditure values from 701 studies. The result: 1,114 activities, 912 of them with MET values measured by calorimetry. Compared with the 2011 update, 303 new activities were added, including, for the first time, separate values for hiking at different gradients and pack weights.

In pure kcal per hour, hiking sits mid-table. On steep climbs with a heavy pack, though, it can match many high-intensity sports. The 2024 Compendium breaks it down in detail for the first time: flat terrain with a light daypack comes in at 3.5 MET, moderate cross-country hiking at 6.0 MET and mountain hiking with a pack of 10 kg or more at 7.8 MET. Steep climbs (11–20% gradient) reach 8.8 MET.

As a rule of thumb, climbing adds another 100–150 kcal per 100 metres of ascent to a base of 350 kcal/h. A hut hike with 1,000 metres of ascent can easily burn 800+ kcal, comparable to an hour of jogging.

Cross-country skiing is one of the most calorie-intensive sports of all, and for good reason: your arms and legs work at the same time. A comparative study by Scheiber et al. found that it takes about 2.5 hours of alpine skiing to use as much energy as a single hour of cross-country skiing.

At a moderate pace (6–8 km/h), you burn 595–680 kcal/h at 70–80 kg. Master the skating technique and push the pace, and you reach MET 13.3, comfortably above 1,000 kcal/h. In race mode (MET 15.5–16.5), peak values of more than 1,300 kcal/h have been documented.

Ski touring is one of the most energy-intensive outdoor activities. The landmark study by Tosi, Leonardi and Schena gave the first quantitative description: at a self-selected speed on a 21% gradient, energy cost is 10.6 J/kg/m, higher than walking or snowshoeing.

A moderate ascent burns 400–700 kcal/h. On intense climbs through deep snow and steep terrain, more than 1,000 kcal/h is realistic. Speed matters too: burn rises in proportion, so going 10% faster costs roughly 3.2% more energy.

A sport's MET value only tells half the story. Five factors can push your actual burn up by as much as 55%, or leave it noticeably lower than expected when conditions are kind.

Your body does not simply stop burning calories after hard training. EPOC (Excess Post-Exercise Oxygen Consumption) describes the raised oxygen consumption after exercise, while your body restores its ATP and creatine phosphate stores, clears lactate and regulates body temperature.

Research shows a clear link to intensity. An easy 30-minute session adds 15–33 kcal. An intense 60-minute session at 70–75% VO₂max adds 76–165 kcal over up to 7.5 hours. The peak: after a 45-minute intense cycling session, participants burned an extra 190 kcal over 14 hours.

For outdoor athletes, that means a ski tour with repeated steep climbs, essentially natural interval training, produces a much bigger afterburn than a moderate walk of the same length.

How much energy does a long ski tour really take? Let's work it out: