Most people don’t do hikes on a regular basis – although once a year could count as “regular interval”. But usually, it’s a part of leisure time, a way of enjoying the scenery or perhaps testing your limits. Probably it’s a combination of all of the forementioned. However, hiking is a very different thing than walking through the park, or running in the city.
Typically, hikes contain unpaved paths, rocky or muddy terrain or even snowfields. Many hikes cover a substantial change in elevation and take you to new heights. Literally, but also figurative: climate zones differ from one side of the mountain to the other one, depending on its location relative to the sun, presence of glaciers and forest.
Precipitation patterns change, temperature drops with altitude and more snow is preserved from the previous winter.
In this blog post, I will explain which parts of your body are being impacted and in which way. This should allow you to be better prepared for any upcoming hikes.
How is your body impacted during a hike?
With hiking, we generally mean a longer, off-the-beaten-track walking activity which often involves carrying a backpack of some sort. This has an impact on your body – and preparing for that impact definitely increases the “fun-factor”.
Walking a long distance obviously impact your cardio-vasculair system: heart, lungs and blood vessels. But also your lymphatic system: the part of the body which drains and secreds fluids into and out from the blood.
This is easily noticeable by increased heart rates, sweat and a higher frequency of breathing.
The second part of your body that’s affected is the muscles, bones and tendons. The effect is both isometric and isotonic.
The third part is the results from friction (blisters, irritation) and fluids: bursitis.
All of these things can be trained, but some take more time than others to adapt. The easiest part to train is (most of) the muscle groups in use. Muscles adapt fast, and it’s only occasionally the case that it’s the muscles that are causing injuries.
Most often it’s the tendons (the strong tissue that connects muscles to bones, to allow movement). The most important thing to remember though is that in hiking it is not the distance that is determining your training goal!
It is not the distance?
No, it is not the distance. The distance itself is largely irrelevant. Distance is easy to train, but how would you be prepared for a mountaineous hike, after doing multiple 30k’s in a week on flat terrain?
It is also not the altitude gained or lost, neither is it the absolute elevation. You can get to great heights, or make very long downhills, or both. Stay up in the mountains for multiple hours to adapt to the altitude. But, none of these will help you either.
Nope, what’s usually beating you up is your feet or back/shoulders or a combination of them. And this is determined by “time on your feet”. Maybe you recognize that shopping is much more exhausting for your body then a continuous walk – even if the distance has been the same.
The factor involved here is “time”. Time on your feet. With our usual sitting behavior, we are not used to standing on our feet for multiple hours on a day. Certainly not with a backpack, which does not only add weight but also changes your center of gravity – which causes you to correct your stance very often, even when unnoticed.
Feet-time: train it!
When planning a hike, I typically look less at the distance to be covered. The most important thing is “time consumed”. A climb of just a few kilometers might take multiple hours. Multiple hours on my feet, with a backpack on my back, going uphill, on a different type of path than my normal forest-walks.
If one would train just for the distance, it’s easy. 38km in 3 days is no challenge for anybody with 2 healthy legs. But it only takes 7 hours (or something like that). Training that distance therefore might be a good mimic of the muscle-intensity, but it’s not going to help you to adjust your feet. These need to be trained as well: your foot-arch and the involved muscles will be stressed for 7-8 hours per day, for 3 days in a row, with a backpack and going uphill and downhill.

But it is not just your feet: it’s the shoulders and back as well. Your shoulders and back will be strained, even if your backpack fits nicely around your hips (as it should). The weight moves about, the touching of the straps across the fabric can cause irritation and flow of all fluids is limited: bursitis in the shoulder isn’t unheard of!
The only way to train this is doing it: train your body to carry a backpack, for multiple hours on a row. Not just sitting, but moving. Alternatively: standing still with your backpack is good exercise too, as it provides time on your feet and isometric load…

This has to do with the type of load on your muscles: isotonic or isometric. With an isometric load, your muscles are contracted but not creating movement: pushing against a wall or planking, as examples.
With an isotonic load, your muscles contract and create movement. Instead of planking, you do push-ups. Isotonic or isometric training both have different purposes and different effects (and effectivity) on building muscles. However, hanging a backpack is largely isometric.
Muscles and tendons
Muscles need to be trained too. Muscle tissue is about the most adaptable tissue in your body, and generally responds to training very quickly. The first thing that is trained is “muscle memory”, or actually mostly the nerve-system that is synchronizing your actions better for better results. This goes very quickly, it’s just a matter of repeating the same exercise. (Anatomy for Runners, Joe Dichary)
It takes longer to activate more muscle tissue and to increase the mitochondria in your muscles: the energy storage in your muscles, which allows for quick contraction or contraction over a prolonged period of time.
Muscles have a very good access to your body’s systems as there is a lot of blood flow through it. With long periods of training, this blood flow increases. This allows your body to move more resources (energy, fluids, proteins, oxygen) and remove more resources (carbon dioxide and other waste products), and have these removed by the multiple organs in your body.
Furthermore, there are your tendons. The tendons have a very limited blood supply and therefore recover more slowly and build up slower. When damaged, they don’t even restore fully to their original function (Essentials of Anatomy and Physiology, Tina Sanders & Valerie C. Scanion). Building the strength in your tendons is very important and require training “in the long run”: multiple years, preferably, but months definitely.
How to train this, is a different subject altogether. Most important to realize:
1. Training tendons takes the most time and must be done carefully: don’t increase loads too fast (both in duration and intensity)
2. The muscle system can adapt in months, with the largest adaptation done in the first weeks.

Cardiovascular system
Obviously, when you have heart issues or suspected heart issues: consult your physician. I am not a doctor, nor do I pretend to be one. I will also not be explaining HOW to best train your cardiovascular system (or any other system, for that matter). But I will explain why.
The reason for this is quite simple: with a better flow of blood through your body, you will last longer. More energy and resources flow through your body and allow you to last longer on fats, rather than on carbohydrates.
This is usually referred to as the lactate threshold or the anaerobic threshold. Let’s be clear; this does not exist. Period. There is no such thing as a threshold. It is a sliding scale, actually. At low intensity activities, the body uses predominantly fats to move you around. When intensity increases, more carbobydrates are added to the mix. At the highest intensities, you do still burn fat, but simply less (as a percentage). In absolute numbers, it might be more.
However, your body cannot sustain the highest intensities for a long time. This has 2 reasons: your body does not hold great reserves of carbohydrates. It’s about 500 grams, or 2000 kcal of energy. This will last for 25-30km of running. And then is fully depleted. Part of this energy supply is stored in your muscles, the rest in your liver. And yes, this can be trained and increased to about 700 grams.
Compared to your fat reserves, it’s almost negligible. My body weight is about 85kg and even with a 10% fat on my body, this would be more than 60,000kcal of energy. Sufficient to run about 1,000 kilometers. Yes, one-thousand.
The second reason though is different: when burning carbohydrates, lactic acid is formed. This in turn is a fuel for your body. But, your body needs to be able to burn it and lactic acid requires a lot of oxygen to use lactic acid as a fuel. This is where the term “acidified muscles” comes from. They are actually running on an oxygen-debt, and lactic acid builds up. After the exercise, your body is still working to get rid of this oxygen-debt, and is burning the waste-product of lactic acid as a fuel.
Back to topic: when the intensity is too high, more lactic acid builds up and your carbohydrates are depleted. When climbing a mountain with a backpack, you can be assured that this will let your heart rate rise.
Being fit and being able to keep your heart rate down when climbing, is a good way to make sure that you enjoy more of the surroundings. It also allows your body in the evening to pump blood through your body to repair tissue and transport waste products to liver and kidneys.
Conclusion: what to train when planning a hike?
Don’t forget the first part we kicked off with: it’s about feet time. Being able to run 30k in 2 hours does not mean that you can hike 30k in 8 hours: the time on your feet is 4 times as long. Carrying a backpack only exacerbates this potential issue.
Training the muscles is very important though – but should not go faster than the time it takes to adjust the strength of your tendons. Strong muscles with weak tendons are a recipe for disaster: you only notice pain in your tendons when its too late…
Most importantly: stay fit. Always. Maintain a good heart rate and take care of your blood vessels. It allows you to enjoy the scenery and recover faster. But not just recover faster: also the training of the forementioned goes faster and more efficient.