Hiking's effectiveness as a stress-relief technique comes from a combination of healthy things that hiking rolls into one. Between aerobic exercise, naturally calming surroundings and the freedom to think and relax freely for extended periods of time, hiking is one of the most effective methods for combating stress on a regular basis.
Relaxing the Mind
One of the strongest ways hiking can relieve stress is through relaxation. Although hiking is aerobic exercise, it need not be strenuous, so it can help tremendously in promoting relaxation through a direct experience of nature up close. The American Public Health Association confirms that just being around nature is enough to markedly increase in relaxation, which helps relieve stress. By hiking on a nature trail or in another natural setting, you can disassociate with the stresses of everyday life and focus instead on the wonder of reality around you.
Invigorating the Body
Hiking also relieves stress through its aerobic exercise component. Consistent aerobic exercise invigorates the body and helps to regulate stress on a chemical basis. Those who hike weekly or biweekly have increased levels of endorphins, norepinephrine, also known as noradrenaline, and a stronger internal system of stress-management -- all of which are thought to reduce stress significantly. The American Psychological Association points out that science is not yet sure which of these factors is the most important in how stress is reduced by aerobic exercise, but all agree that exercise such as hiking helps reduce stress through one or more of these chemical mechanisms.
Working the Brain
Another way hiking attacks stress directly is through an often overlooked aspect in the hiking repertoire: the freedom to think without distraction. While some hikers prefer to use their time hiking to fully take in the sounds of nature around them, many are able to take full advantage of the relative silence to spend time thinking deeply on issues that matter to them. The combination of aerobic exercise with deep thinking is more effective at strengthening the body's internal system of stress management than exercise alone. The editors at Help Guide point out that thinking deeply while exercising can relieve stress so long as the topic isn't itself a stressor. Listening to class lectures or reviewing notes for work are not appropriate for stress-free hiking, but listening to podcasts and audiobooks can be a very good idea for any hiker.
Fulfilling the Spirit
Modern technology allows hikers to take advantage of yet another time-honored method of stress relief: listening to music. The book "The Principles and Practice of Stress Management" notes the particular effectiveness of music as stress relief, especially when paired with aerobic exercise such as hiking. Not only does it serve to calm the nerves, but it also helps to establish a rhythm of hiking, which accentuates the effectiveness of the body's aerobic exercise. The combination of endorphins released between the two seemingly disparate activities can deal with stress much more efficiently overall. As a side-benefit, listening to music also significantly helps the brain think more clearly and relax the mind as it helps the body exercise more efficiently. Music has the capability of focusing the effects of every aspect that hikers use to eliminate stress.
While hiking is an excellent way to relieve stress, it is important to always be prepared on a hike. Bring a first aid kit, extra water and a mobile phone that gets reception in the area. Neglecting to bring any of these will result in a stress increase, not decrease, should an accident occur.