According to Healthy Families BC there are several benefits of hiking, which include but are not limited to: 

Lower stress levels-Hiking is usually done in beautiful scenery, which would surely make one less stressed

Improved mood-Exercise improves mood in general 

Enhanced/improved mental well-being-This is connected to improved mood and lower stress levels. 

Reduced risk of heart disease- It is well known that more exercise leads to improved physical health, and even longer lives. Walking is a very low impact exercise, and while one gets all the cardiovascular benefits of other aerobic activities but without all the strain and stress on your body.

Lower blood pressure- It is also well known that hiking lowers blood pressure. High blood pressure can lead to heart attack, stroke, and other serious problems. 

Lower cholesterol levels, improved control over healthy weight, and lower body fat-Hiking is a method that can lower cholesterol levels, just like other methods of exercise.

Improved bone density and improved osteoarthritis outcomes- Hiking and walking can strengthen the bones.