A cardiologist's warning after the hospitalization data for marathon runners: "They're not aware."

Madrid hosts the 47th edition of the Madrid Marathon this Sunday, with an expected participation of 45,000 runners. Many of them are professional athletes, but there will also be plenty of amateurs who will tackle the 42 km and 195 m race.

This same month, the half marathon (21 km and 97 meters) was also held in the Spanish capital, with 21,000 participants. But what stood out this year was that up to 42 people had to be treated by emergency services.

This figure is significant, according to Dr. Juan Carlos Portugal del Pino in a statement to the specialized magazine Runner's World . "Out of 21,000 participants, 42 were treated, which is a high figure. Definitely above what we were aiming for, which would be to not have to treat any of them," the doctor says.

"The problem is that people are venturing into tests they're not prepared for. It's fun and challenging, but you have to be prepared, and to do that, it's important to know yourself and your body, but above all, to be aware of the challenge and prepare accordingly, based on your previous level and the recommendations of experts," adds the doctor, who specializes in Clinical and Sports Cardiology at Medical Tuset Barcelona (MTB) and is a member of Top Doctors.

"A half marathon can last between two and two and a half hours, during which we'll be using all of our body's resources , and many people aren't aware of this," the doctor continues.

"Personally, I think people are losing a bit of respect for these events. More and more people are signing up for triathlon- or Ironman -type events, but they aren't sufficiently prepared for them," says Portugal.

"You can run a half marathon at different intensities, but people who are inexperienced and unprepared tend to go harder than they should at the beginning of the race, without taking into account that they should manage their energy and body capacity ," the doctor reflects.

"If you push yourself hard but aren't used to it, your body may have the capacity to store glycogen , but it won't have enough enzymes to release it quickly enough. And the body's reserves are primarily for the brain, heart, and liver, not the muscles," says Dr. Portugal.

"We have to work at an intensity that allows us to mobilize our reserves and, with the additional intake of gels, sustain the effort for the entire duration. We also have to train our stomach to be able to efficiently assimilate the gels," the doctor explains.

So how do you prepare? "To be able to run a half marathon, you need to run about 40 km during the week. Some people sign up for such a race and run about 15 km a week, and that's not enough. Lack of experience is a decisive factor because they approach the race without realizing how long the effort will last. This causes them to start very quickly and have a very good first part and a rather poor second part, or they drop out," says Portugal.

"I believe you can run a half marathon by planning a weekly volume that's double the actual race you'll be running. And to do that, you have to increase your mileage by 5 to 10% per week for experienced runners. For those who don't run, they should join a club or train with a coach, with a minimum of four to six months of conscientious preparation, depending on their base level," says the doctor.

Furthermore, Portugal points out that "the time of exposure to exertion is considerable, almost two hours or more, and it is always recommended that, if the patient is over 35 years old , they undergo a prior cardiac check-up. In these long-distance races, we will not only face exertion, but a combination of exertion and fatigue, testing the limits of our physical and metabolic tolerance."

Dr. Portugal asserts that "it doesn't make sense to offer general recommendations regarding nutrition and training because we don't all have the same level, the same weight, or the same capacity for effort."

"Racing often provides generalized training plans that don't take into account each person's context , habits, consistency, sleep patterns, and often not even age," the doctor continues.

"The best thing would be to have a coach and a nutritionist to guide you through the test preparation so we can assess each person's physical condition. What we want is for people to take the test, and we could all be capable of doing so, but with proper training and preparation," he adds.

"Enjoy the journey, set small challenges for yourself, and when you feel comfortable, move on to the next one. For example, don't try to run a marathon if you're not comfortable finishing a half marathon in two hours or two hours and ten minutes, otherwise it would be too long. And don't jump to a half marathon if you're not yet comfortable finishing a 10K in 50 or 60 minutes," Portugal concludes.