The marathon is track-and-field’s ultimate test and is one of the most physically and mentally demanding challenges an athlete can face.

That’s why it’s critical to perfectly understand what kind of shape our body is in, in order to carry out a safe, personalized training session with guaranteed results. In fact, there are numerous athletic events that require their participants to undergo a medical exam beforehand.

But… what tests should we take in order to get a thorough and reliable exam that insures optimum understanding of our health and the shape we are in?

The top experts in the field recommend the following three:


With the stress test we can see how well our lungs work, and go deep into heart rate data. These indicators fully show the potential output of each athlete and determine the 5 work zones of our preparation:

  • Zone 1. Regenerative and Fat-burning: Easy, relaxed pace with rhythmic breathing. Basic level aerobic training, reduces stress.

  • Zone 2. Extensive Aerobic: Comfortable pace with slightly heavier breathing, easily able to speak. Basic cardiovascular training, fast recovery rate.

  • Zone 3. Intensive Aerobic: Moderate pace, more difficult to hold a conversation. Improved aerobic capacity and optimal cardiovascular training.

  • Zone 4. Extensive Anaerobic: Fast, somewhat uncomfortable pace with forced breathing. Improved endurance and anaerobic threshold, improved speed.

  • Zone 5. Intensive Anaerobic: Sprint pace, difficult to maintain for much time, very forced breathing. Anaerobic and muscular resistance, increased strength.

The main metrics to pay attention to in a stress test are:

  • Heart Rate Threshold: Heart rate measures the number of times per minute that the heart beats. The heart rate threshold determines the range of pulsations in which it is best to work when training for a race. This is the zone where the most important improvements take place and where our health is not at risk.

  • Maximum Heart Rate: This is the maximum number of beats our heart can reach while staying in a safe training range. We must always know our own limits. Plus, there are certain speed exercises where these numbers can be reached quickly.

  • Recovery Heart Rate: Rate at which our heart should beat after physical exertion to be considered prepared for an optimal, healthy recovery.

  • Maximum Oxygen Volume (VO2): Maximum oxygen consumption capacity. The greater our VO2, the greater our cardiovascular capacity.


It is important to know that the goal of a marathon should not be to lose weight, and that a marathon puts a lot of pressure on the joints of those who are not at an appropriate weight. It is important to know our body mass index and our limitations before starting.

The goal is to get to the competition with a BMI between 20 and 25. This can be calculated with the following formula:

BMI=weight (kg) / height (m) squared

Sometimes, the estimated BMI in elite athletes isn’t accurate enough. To get a more exact analysis, we can proceed to calculate the body fat index, which depends on other factors such as age, sex, weight and lifestyle. With this measurement we get information about body fat percentage, bone weight and muscular weight. These three indicators are known to have a direct, close relationship with the performance of the athlete, along with the chance of injuries.


Thanks to the Doppler echocardiogram we can understand our cardiac structure. This test plays an essential role: it detects and rules out possible heart diseases that can cause complications during preparation for the race or the race itself.

The echocardiography is a diagnostic ultrasound procedure that generates high-quality images of the heart, its cardiac activity and flows. In a test as demanding as the marathon, it is essential to begin preparation as safely as possible.

Less than 10% of people who run a marathon undergo a Doppler echocardiogram. However, unfortunately each year in Spain there is an average of 127 sudden deaths of people who exercise, the majority of which are caused by cardiovascular problems that had not been previously detected.

With a full analysis of all these results we can determine if our body can safely enjoy an athletic activity as intense and demanding as the 42km that separate us from the finish line. 

Keep preparing for your great challenge with us! Download the training plans for your second week of preparation here.


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