Is running truly good for your health, or can it end up being harmful?

Hello, Alejandro,

I was asked this question recently and I found it particularly interesting, because the answer is not simply yes or no.

Running can be an extraordinary tool for improving our health and longevity. But, as with many things in medicine, the dose, intensity, recovery and context matter just as much as the activity itself.

After reviewing the scientific literature, my conclusion is fairly clear: for most people, running in an appropriate way provides far more benefits than risks. Problems tend to arise when we run too much, too fast, or without having prepared the body beforehand.

A powerful metabolic stimulus

Running considerably increases energy expenditure and can help maintain a healthy weight, reduce visceral fat and improve insulin sensitivity and metabolic control.

But its benefits go far beyond burning calories.

Running is an important stimulus for our cardiovascular system. With appropriate training it can increase cardiorespiratory capacity and VO₂ max, improve cardiovascular function and promote a more efficient use of oxygen.

And this is particularly relevant because good cardiorespiratory capacity is consistently associated with a lower risk of cardiovascular disease and mortality.

We also train our brain

Many people are familiar with that sense of wellbeing after running that we call runner's high.

Exercise produces changes in different neurotransmission and neuromodulation systems related to endorphins, endocannabinoids, dopamine and serotonin.

In addition, physical exercise is linked to changes in BDNF (Brain-Derived Neurotrophic Factor), a protein involved in neuronal plasticity, learning and memory.

This is why running regularly can help reduce stress, improve mood, support sleep and form part of a preventive strategy against cognitive decline and certain depressive disorders.

Exercise as hormesis

There is another concept I find especially interesting: hormesis.

When we run, we temporarily subject the body to physiological stress: energy demand increases, the mitochondria work harder, oxygen consumption changes and our cardiovascular, muscular and nervous systems must adapt.

When that stimulus is appropriate and we subsequently allow sufficient recovery, the body responds by adapting.

In a sense, training involves applying a small dose of stress in order to achieve a positive adaptation afterwards.

The problem arises when we accumulate stimulus after stimulus and remove recovery.

At that point we stop adapting and simply accumulate fatigue.

Where do the problems begin?

In my view, the problem is often not running itself; it is how we run.

Too fast.

Too hard.

Too many kilometres.

And too soon.

A sedentary person should not progress to running long distances in just a few weeks simply because they feel cardiovascularly capable of doing so.

The heart may adapt before the tendons, bones and certain musculoskeletal structures do.

This is why an inappropriate increase in training load can contribute to tendinopathies, patellofemoral pain, plantar fasciitis, periostitis or stress fractures, among other injuries.

Not every run has to leave us exhausted

There is still a 'no pain, no gain' culture that I consider quite misguided.

A good training session is not one in which you finish completely drained every single day.

A large part of endurance training can be carried out at low or moderate intensities, reserving truly intense sessions for specific moments in the training plan.

Training continuously at relatively high intensities, without sufficient rest and with inadequate energy intake, can increase fatigue, impair recovery and reduce performance.

Cortisol rises physiologically during exercise, and that is not a bad thing: it is part of our normal response to effort. The problem is a context of chronic physiological stress, insufficient recovery and low energy availability.

For this reason, we should not automatically interpret certain physical changes in runners as a consequence of 'having high cortisol'. Physiology is considerably more complex than that.

Running does not replace strength training

This is probably one of the messages I am most keen to convey.

If you want to age well, you should not limit your physical activity solely to cardiovascular exercise.

We need to preserve muscle.

Muscle mass plays a role in mobility, glucose metabolism, stability, fall prevention and our future independence.

Running provides muscular stimulus, particularly in the lower limbs, but it does not replace a complete strength training programme.

As the years pass, this becomes even more important.

For this reason, if I were to design a longevity strategy, I would combine cardiovascular exercise + strength training + mobility + adequate recovery.

We must also ensure sufficient energy and protein intake through nutrition, especially when training volume is high.

What about footwear?

Here too we must avoid overly absolute statements.

There is a great deal of debate about minimalist and maximalist shoes, drop, cushioning and running technique. We do not have sufficient evidence to state that a highly cushioned shoe is necessarily harmful, nor that running barefoot is better for everyone.

What matters is individual biomechanics, progressive adaptation, foot and full kinetic chain strength, training load and using footwear in which the person can run comfortably.

Suddenly changing shoe type or running technique can also cause injuries.

So, doctor, do you recommend running?

Yes. For a person with no medical contraindications, I absolutely recommend cardiovascular activity, and running can be a magnificent way to achieve it.

It is accessible, relatively affordable, independent and extraordinarily easy to adapt to each person's level.

But I do not recommend turning every outing into a competition against ourselves.

Running more kilometres does not automatically mean being healthier.

Running faster does not either.

My approach would be far simpler: run enough to stimulate the body, recover enough to allow it to adapt and train for strength to preserve muscle and functionality.

And listen to your body.

If every week you are more tired, sleeping worse, your performance is declining, repetitive injuries are appearing, you are losing strength or you are beginning to train out of obligation rather than enjoyment, your body is probably telling you that the balance between training and recovery needs to be reviewed.

The true purpose of exercise should not be to finish exhausted.

It should be to build a body that is metabolically healthier, cardiovascularly more efficient, muscularly stronger and more functional for as many years as possible.

That, to me, is training for health and for longevity.

Kind regards,

Doctor Florian A. Vallecillo Cabrera