The Effects of Resistance Training on the Course of Cancer Treatment

„Body Mass Index (BMI)“ is a measure that enables one to check whether the body mass proportions are suitable for growth. This measure can be calculated using the following formula: BMI = body weight (kg) / growth² (m). According to the World Health Organization (WHO), the „Body Mass Index (BMI)“ may be helpful in assessing the state of health, however, the result should be handled with caution, as this formula does not take into account the level of fat tissue, which is crucial to making the decision to start the weight loss process. A low „Body Mass Index (BMI)“ can conceal excessive obesity, while a high „Body Mass Index (BMI)“ may be due to a large amount of muscle.

During the treatment of cancerous diseases, we often experience weakness, malnutrition, and body destruction. Muscle tissue, similar to fat tissue, serves as an energy store, however, muscles also contain amino acids, which can be crucial in the treatment process. Muscular weight is not only used to lift weights, achieve better athletic performance, or build an attractive physique. The more muscle a person has, the better their body can alleviate inflammation caused by excessive fat tissue. Conversely, a lower muscle mass can lead to inflammation and insulin resistance, which can negatively affect the course of cancer. In patients with greater muscularity, the treatment process can be more effective, as a higher dose of chemotherapy can be administered. Furthermore, it has been found that in individuals with less muscle mass, the risk of various infections, especially after surgery, increases, and their hospital stay is longer than in those with more muscle mass. It has also been observed that individuals with more muscle mass more frequently overcome the disease and return to health (B.J. Caan et al. 2018).

A British study involving over 5 million participants found that the BMI index has a significant impact on the occurrence and progression of 17 out of 22 cancers, including liver, colon, or breast after menopause (K. Bhaskaran et al. 2014). Although obesity is associated with an increased risk of premature death, the so-called obesity paradox occurs in the course of cancer. This means that excess body weight can always help in the fight against cancer and increase the chances of a milder disease. In 2017, a study was conducted on a group of 12,590 women aged 18-80 with a diagnosis of breast cancer in stages I-III. Each participant had to provide their weight and height in the third month after diagnosis and in the eighteenth month after diagnosis. The results showed that a significant weight loss was associated with an increased risk of death, regardless of treatment and prognostic factors (E. M. Cespedes Feliciano et al. 2017). Similar studies were conducted in California on a group of 2781 patients with a diagnosis of colon cancer in stages I-III. The results showed that weight loss was associated with an increased risk of death. Each 5% decrease in initial weight increased the risk of death by 41% (J. A. Meyerhardt et al. 2017). These results suggest that weight reduction during cancer treatment is not always the best option, even in overweight individuals.

Sustaining an active lifestyle is essential for maintaining health and physical fitness over an extended period. The body structure of an individual who is physically active with a large amount of muscle mass can bring many benefits and even save the lives of several people with cancer. These individuals more often conquer cancer, the disease course is milder in them, and they recover more quickly. Moreover, the risk of systemic infections, especially after surgeries, decreases. The treatment period is also not the best time for weight reduction. When someone undergoes chemotherapy, their body is weakened and undernourished, so the stored energy in the muscles and fat tissue and amino acids may be indispensable for recovery.