Regardless of the intensity, walking and hiking are good things to do. But, the ability to burn calories on a hike varies in relation to the terrain, speed, intensity, and pack weight.
So let's go into the four factors that influence the calories burned on a typical hike:
Hiker's weight
Unsuprisingly, a hiker's weight has an impact on the calories lost on a typical hiking session. Quite simply, for hikers with higher body weight, it is necessary to work harder to complete the hiking course.
The need to work harder means more calories are lost per hour. For instance, a hiker weighing in the region of 185 pounds is likely to drop 615 calories per 60-minute hike, while this will increase to 750 calories for a 225 pound hiker.
Backpack weight
In the same way as a heavier hiker will burn more calories than a lighter one, the same is true of the extra weight carrid.
A heavy load on the back is certain to mean more calories are burned while on the hiking trail. A combination of rugged terrain and heavy pack gives the perfect opportunity to burn plenty of calories on the trails.
For instance, a pack loaded with essential supplies at 42 pounds can help to increase the calorie burn to 650 for a female hiker or 765 for a male hike. This is assuming the trail condition is rugged and elevated.
For hiking trails of 3 miles or shorter isn't likely to demand a lot of supplies to complete with safety. Water is likely to be the heaviest supply to pack, although on certain elevated or difficult trails it might be necessary to pack special hiking or climbing equipment.
However this will not up your calorie count too much, but you can address this with the next factor, speed.
Speed
Hiking a 3 mile round trip is a relatively short hiking distance, although the time-frame to finish can differ from 30-120 minutes. The completion time will of course differ based on the average walking speed.
For instance a generally flat trail is easier and makes it possible to hike at an average speed of 4 miles per hour, while an uphill hike is more difficult and might cut the average speed to approx 1 mile per hour.
For instance, the hiker at a walking speed of 2 miles per hour and weighing 165 pounds has the potential to lose 185 calories per 60 minutes, while a faster walking speed of 3.5 miles per hour will up the calorie loss to 275 per 60 minutes.
Average speed is influenced by several factors, including the terrain and fitness levels, which leads us nicely on to the final factor - the type of terrain you are trekking across.
Terrain
A flat vs an uphill trail has a significant impact on the ability to burn calories. A rugged trail with noticeable elevation gain is certain to be the most desirable option for those wishing to increase the calorie burn.
For instance, a moderate elevation gain for the hiker weighing 185 pounds has the potential to burn approx 625 calories per 60 minutes, while this will increase to about 750 calories for the hiker navigating the steep uphill terrain.
So if you want to increase the burn, find some good inclines or rough terrain that will work your body more and build up that calorie count.
Summary
Hiking will burn different amounts of calories depending on the hiker, the terrain and the intensity.
You should tailor these factors to your overall goals and the trail length - there is no point going off at a storming pace if you have to cover 20 miles in a day, you will burn out.
Also, if you want to have an all-over workout as well as some extra stability, look at using trekking poles...your knees and ankles will love you for this too, especially on rougher terrain.