Is increased lactate during exercise dangerous for cancer patients: An editorial

Dear Editor-in-ChiefLactate can be a key factor in cancer tumor progressionOne of the clear indicators of cancerous tumors is an uneven distribution of oxygen, resulting in the presence of both hypoxic and normoxic areas within the tumor (Goodwin et al., 2015). Consequently, these conditions can contribute to the acidity of the tumor environment (Goodwin et al., 2015). The significant increase in lactate levels observed in cancerous tumors is primarily attributed to the heightened activity of the glycolysis cycle (Goodwin et al., 2015), a phenomenon identified by Otto Warburg in 1927, known as the Warburg effect (Pérez-Tomás & Pérez-Guillén, 2020). Despite the common misconception that lactate is a waste molecule, emerging evidence suggests that lactate may actually play a role in promoting cancer progression, particularly in support of cancer cells (Lavín-Pérez et al., 2023; Pérez-Tomás & Pérez-Guillén, 2020). Therefore, there is strong evidence to support the notion that lactate serves as the primary fuel to fulfill the anabolic requirements of cancer cells, potentially serving as a key factor in cancer growth (Lavín-Pérez et al., 2023; Pérez-Tomás & Pérez-Guillén, 2020). Given the complex physiological conditions associated with cancer, it raises the question of whether exercise is appropriate for cancer patients or not.Lactate, exercise, and cancerConsidering these complex physiological conditions, whether exercise in cancer patients can be appropriate (Lavín-Pérez et al., 2023).  Several studies have investigated the effect of exercise during cancer with different mechanisms that have reported the positive effect of exercise to improve psychological or immunological effects (Lavín-Pérez et al., 2023). However, the special concentration of exercise, lactate, and its relationship with tumor growth has yet to be specifically  investigated. Physiologically, exercise with any intensity can increase lactate (Stallknecht et al., 1998). One of the factors that can have a significant effect on increasing lactate is the intensity of training (Stallknecht et al., 1998). According to Brooks et al., lactate is the largest myokine in concentration and dynamic range and the most diverse in metabolic and physiological regulation (Stallknecht et al., 1998). In the past, lactate was believed to be produced in anaerobic conditions. However, in recent years, the theory has been proposed that lactate is also produced in completely aerobic conditions (Stallknecht et al., 1998). Therefore, aerobic and anaerobic training will increase lactate (Stallknecht et al., 1998). As the intensity of training increases, the ratio of NAD+ to NADH increases. As a result, fat oxidation decreases, focuses on the glycolysis cycle, and increases lactate (A factor that can be harmful to cancer (Stallknecht et al., 1998). Also, common research supports the hypothesis that lactate increase during exercise can lead to angiogenesis and is one of the key factors of this process (Ahmadi Hekmatikar et al., 2019; Hubbard, 1973; Khoramipour et al., 2020). It seems that lactate can 1) through its effect on factors such as vascular endothelial growth factor and 2) as an important cardiac fuel and metaboreflex regulation leading to greater cardiac output for angiogenesis. On the other hand, considering that there is hyperlactatemia in cancer and the long history of cancerous tumors absorbing lactate, researchers are looking to prevent lactate transport in tumors by blocking MCTs. Accordingly, the development of therapies that limit lactate exchange and signaling within and between cancer cells should be a priority in cancer research, contrary to the physiological effects of exercise.Finally, the hypothesis that lactate could be suitable for cancer patients during cancer seems false, given the strong results. Both directly, as an energy source, and indirectly, as a gluconeogenic precursor, lactate plays a major role in the bioenergetics and self-sufficiency of cancer cells. Acutely and chronically, exercise has positive physiological effects that cannot be suitable for cancer patients. On the other hand, the tumor environment is such that lactate is one of its key fuels for aggressiveness and growth. On the other hand, lactate itself induces angiogenesis. Physiological changes that occur due to exercise can increase lactate, angiogenesis, and lactate transporters, which can benefit the tumor. Physiological changes that occur due to exercise can increase lactate, angiogenesis, and lactate transporters, which can benefit the tumor. However, this study suggests that researchers should focus on exercise and the effects of lactate on cancerous tumors in future studies

The effect of aerobic exercise after exposure to black carbon particulate matter 2.5 on expression of NF-κB and TNF-α genes in the lung tissue of male rats

Background: The aim of the present study was to investigate the effect of aerobic exercise after exposure to black carbon particulate matter 2.5 (PM 2.5) on expression of NF-κB, and TNF-α genes in the lung tissue of male rats. Materials and Methods: Twenty-four male Wistar rats (mean weight, 279.29±26.97 g) were randomly divided into four equal groups: 1) control (without any intervention), 2) without aerobic exercise and with exposure to PM2.5 black carbon, 3) aerobic exercise without exposure to black carbon, and 4) aerobic exercise after exposure to PM2.5 black carbon. The aerobic exercise protocol was performed at 50 the maximal speed of each group for 4 weeks 15 minutes after exposure to black carbon particles in the chamber. Animals were sacrificed 24 hours after the last training session and exposure to black carbon particles. The expression of NF-κB and TNF-α genes were analyzed in the lung tissue of rats by the real-time PCR. Results: A significant difference was found in the NF-κB expression between the group 1 and other groups and also there was a significant difference in the TNF-α expression between the group 2 and group 3 after exposure to black carbon in the lung tissue of male rats. Conclusion: The findings show that aerobic exercise after exposure to the black carbon particles (PM2.5) is associated with adjustment in lung inflammatory factors. It seems that these changes in part are associated with a lower risk of inflammatory pulmonary disease

THE EFFECT OF ENDURANCE, RESISTANCE AND CONCURRENT TRAINING ON THE HEART STRUCTURE OF FEMALE STUDENTS

he aim of this study was to compare the effect of endurance, resistance and concurrent training on the heart structure. Thirty-nine untrained female students (mean age 24±2.58 yrs) were randomly divided into four groups: Control (C; n=9), Endurance (E; n=10), Strength (S; n=10) and Concurrent (SE; n=10).E group training consisted of running at 65% of maximum heart rate (MHR) for 16 min per training unit during the first week, reaching 80% of MHR for 30 min during the 8th week. S group training consisted of performing four leg presses, bench presses, pull down curls, and leg curls. During the first week, the training was performed at 50% of one repetition maximum (1RM) in 2 sets with 10 repetitions. The intensity of training increased to 80% 1RM in 3 sets and 6 repetitions during the 8th week. The SE training included the sum of the training performed by the E and S training groups. Left ventricular end diastolic and systolic diameters, post-wall thickness, left ventricular mass and mass index and septum wall thickness were measured by m-mode and 2-D echocardiography as the structural parameters. The end diastolic diameter in E and SE groups, the ventricular end systolic diameter, left ventricular mass and mass index of the SE group after the training increased (P≤0.05). In comparing the groups, only the increase of the end diastolic diameter in the SE group was significant (P≤0.05). The 8 weeks of concurrent training compared with endurance or resistance training alone resulted in a significant increase in left ventricular end diastolic diameter. However, no significant differences were found for any other measured variables

Prevalence of Overweight and Obesity Among Iranian Preschoolers: Interrelationship With Physical Fitness

BACKGROUND: The preschool years are a crucial time to study the determinants of childhood obesity, as it is when eating and physical activity habits are becoming established. The purpose of this study was to compare the prevalence of overweight and obesity among preschoolers living in the capital of Iran and to determine relationships between overweight and obesity and selected motor- and health-related fitness parameters. MATERIALS AND METHODS: This exploratory cross-sectional study was conducted with 190 boys and 191 girls aged 5-6 years. Study children were selected from the kindergartens in Tehran, the capital of Iran. All children underwent anthropometric, motor- and health-related fitness tests. Height, body mass, body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR) and percentage of body fat (PBF) were measured for anthropometric assessments. Sit-and-reach, modified sit-ups, modified pull-ups, the 4 m × 9 m shuttle run, the 20 m sprint test and the 20 m multistage shuttle run test were measured for motor- and health-related fitness tests. Overweight and obesity prevalence was determined by the International Obesity Task Force, Centers for Disease Control and Prevention and World Health Organization standard criteria. RESULTS: International Obesity Task Force criteria indicate almost 12% (23/190) of boys and 22.5% (43/191) of girls were overweight or obese with 4.73% (9/190) of boys and 10.99% (21/191) of girls in the obese category. Significant correlations were found between modified pull-ups test and body mass, BMI, WC, WHR, WHtR, PBF in boys and modified pull-ups and modified sit-ups tests were significantly correlated with body mass, BMI, WC, WHR, WHtR, and PBF in girls. Compared to their counterparts, overweight and obese boys demonstrated inferior performance in modified pull-ups and predicted VO2max and overweight and obese girls demonstrated inferior performance in modified pull-ups, modified sit-ups, 4 m × 9 m agility shuttle run and predicted VO2max. CONCLUSION: This study highlighted the relatively high prevalence of overweight and obesity in both genders of preschoolers and found that overweight and obesity were associated with poor fitness performances. The findings provided evidence to support the establishment of tailored physical fitness intervention programs to manage and prevent obesity in preschoolers

INFLUENCE OF MUSIC TYPE LISTENING ON ANAEROBIC PERFORMANCE AND SALIVARY CORTISOL IN MALES ATHLETES

Music has been widely recommended as a technique to enhance the psychophysical state of participants in sport and exercise. However, there is scant scientific evidence to clarify its proposed benefits. Therefore, the aim of this study was to determine the effect of fast and slow rhythm of music on anaerobic performance and salivary cortisol concentration in trained men. Thirty male physical education college students (ages: 25.66±3.89 yr, height: 176.65 ± 7.66 cm, body mass: 78.45±16.20 kg) voluntary participated in this study and divided to three groups: fast music, slow music, and no music(control). All subjects performed the coninghum test following a 20% grate and 14.3km/h speed on the treadmill. For measuring of cortisol, not stimulated samples of saliva collected, 15 minutes befor and immediately 5 and 30 minute after the exercise. No significant differences were found in anaerobic performance among the three groups in pretest indicating homogeneity of the groups. However, salivary cortisol no significant in anaerobic performance 5 and 30 minute after exercise as well. Summarily, Music doed not have a positive effect on performance, this study provided some support for the hypothesis that listening fast and slow music not significantly impacted during supramaximal exercise

The Effects of Aerobic Exercise on NF-κB and TNF-α in Lung Tissue of Male Rat

Background:Regular aerobic exercise improves theBackground: Regular aerobic exercise improves the inflammatory status in different lung diseases. However, the effects of long-term aerobic exercise on the lung response have not been investigated. The present study evaluated the effect of aerobic exercise on the lung inflammatory.Materials and Methods: 12 adult male Wistar rats were divided to 2 groups: A: control (n=6), B: aerobic exercise (five times per week for 4 week; n=6). The gene expression of NF-κB and TNF-α were analyzed in lung tissue by Real time–PCR. In order to determine the significant differences between groups independent t-test were used.Results: Aerobic exercise inhibited the gene expression of NF-κB and TNF-α. But there was no significant difference between A and B groups for TNF-α and NF-κB.Conclusion: We conclude that four week aerobic exercise decrease inflammatory status in lung tissue. Our results indicate a need for human studies that evaluate the lung responses to aerobic exercise

The effect of aerobic exercise after exposure to black carbon particulate matter 2.5 on expression of NF-κB and TNF-α genes in the lung tissue of male rats

Background: The aim of the present study was to investigate the effect of aerobic exercise after exposure to black carbon particulate matter 2.5 (PM 2.5) on expression of NF-κB, and TNF-α genes in the lung tissue of male rats. Materials and Methods: Twenty-four male Wistar rats (mean weight, 279.29±26.97 g) were randomly divided into four equal groups: 1) control (without any intervention), 2) without aerobic exercise and with exposure to PM2.5 black carbon, 3) aerobic exercise without exposure to black carbon, and 4) aerobic exercise after exposure to PM2.5 black carbon. The aerobic exercise protocol was performed at 50% the maximal speed of each group for 4 weeks 15 minutes after exposure to black carbon particles in the chamber. Animals were sacrificed 24 hours after the last training session and exposure to black carbon particles. The expression of NF-κB and TNF-α genes were analyzed in the lung tissue of rats by the real-time PCR. Results: A significant difference was found in the NF-κB expression between the group 1 and other groups and also there was a significant difference in the TNF-α expression between the group 2 and group 3 after exposure to black carbon in the lung tissue of male rats. Conclusion: The findings show that aerobic exercise after exposure to the black carbon particles (PM2.5) is associated with adjustment in lung inflammatory factors. It seems that these changes in part are associated with a lower risk of inflammatory pulmonary disease

The Effect of Aerobic Interval Training and Massage Therapy on C-Reactive Protein and Cardiorespiratory Fitness in Cardiovascular Patients after Coronary Artery Bypass Graft

The purpose of this study was to investigate the effects of an 8 week period of aerobic interval training and massage therapy on changes in C-reactive protein (CRP) level and cardiorespiratory fitness in cardiovascular patients after coronary artery bypass graft. The study population consisted of patients who had undergone a coronary artery bypass graft and at least one month had passed since their surgery. 60 patients met the study inclusion criteria and were willing to cooperate; they were divided randomly into three groups (n = 20) as follows; interval, massage therapy and a control. Subjects in groups taking interval training and massage therapy were administered three sessions per week for eight weeks. 48 hours before and after eight weeks of exercise, subjects were measured for peak oxygen consumption and blood samples were taken. Results of the present study show that 8-week programs of regular exercise and massage therapy resulted in significant reduction of CRP of 42% and 25% respectively (P<0.05). Peak oxygen consumption values after eight weeks of regular exercise showed a significant increase (22% in interval exercise and 17% in massage therapy (P<0.05). In general, these findings show that 8-week programs of aerobic interval training and massage therapy significantly reduced serum CRP value and caused a significant increase in peak oxygen consumption in patients with coronary artery bypass graft. These changes can be effective for prevention of sudden death and cardiovascular problems after bypass surgery. Also, interval training was more effective on reducing CRP and increasing peak oxygen consumption than massage therapy