PHYSICAL EXERCISE AND INTERMITTENT FASTING
The word fasting can be defined by the absence of food intake in a certain period of time (Maughan, Fallah & Coyle, 2010). Fasting periods are a challenge for the control of metabolic homeostasis, since there is a mismatch in the level of metabolic pathways, as there is a reduction in muscle and liver glycogen content, a drop in insulin levels, which will culminate in the process of neoglucogenesis, as well as in the increased mobilization of fatty acids, which is one of the main energetic substrates (Cahill et al., 1966). Intermittent fasting is a widely used dietary strategy. This is characterized by periods of caloric intake interspersed with a fast greater than the duration of sleep. There is evidence that intermittent fasting has beneficial effects in obese and hypertensive people, diabetes mellitus and atherosclerosis. This is due to an increase in metabolic efficiency, an increase in the use of triglycerides in adipose tissue and a reduction in inflammatory factors (Longo & Mattson, 2014).
The literature states that one of the main chronic adaptations promoted by the continuous practice of physical exercise, mainly from aerobic stimuli, is an increase in the number and mitochondrial density, an adaptation that gives a greater endurance capacity and optimization in the mobilization of energy substrates of individuals subjected to these conditions (Jung & Kim, 2014; Tabata, 2019; Tanaka et al., 2019).
In a study carried out, the effects of intermittent fasting associated with anaerobic stimuli and endurance capacity for 10 consecutive days were evaluated. The results showed that, in the first two days of intervention, there was a significant reduction in potency and endurance capacity, compared to those who were not fasting. However, the authors observed a tendency to return to performance after the fourth day. Thus, the authors of the study suggest that the negative effects found on the second day may be associated with the acute impact of the energy deficit generated at the beginning of the dietary intervention, however they describe that a possible physiological adaptation may occur over time, which explains the return of these parameters to baseline levels (Naharudin et al., 2018).
According to the articles analyzed, it is observed that intermittent fasting can confer negative results in the response to aerobic and anaerobic tasks, as well as in lean mass gains. However, the reduction in performance may be associated with the intervention time, since two months does not seem to affect performance, even with a daily reduction of 650 kcal.
The literature demonstrates that the combination of fasting and physical exercise is able to confer metabolic changes and a reduction in body adiposity, however, it can cause negative effects on physical performance.
Before starting any diet, fasting or physical exercise, you should consult with certified professionals in the respective areas. These will guide you in the best way according to your goals.
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