Continuous Aerobic Training in Individualized Intensity Avoids Spontaneous Physical Activity Decline and Improves MCT1 Expression in Oxidative Muscle of Swimming Rats

Abstract

Although aerobic training has been shown to affect the lactate transport of skeletal muscle, there is no information concerning the effect of continuous aerobic training on spontaneous physical activity (SPA). Because every movement in daily life (i.e., SPA) is generated by skeletal muscle, we think that it is possible that an improvement of SPA could affect the physiological properties of muscle with regard to lactate transport. The aim of this study was to evaluate the effect of 12 weeks of continuous aerobic training in individualized intensity on SPA of rats and their gene expressions of monocarboxylate transporters (MCT) 1 and 4 in soleus (oxidative) and white gastrocnemius (glycolytic) muscles. We also analyzed the effect of continuous aerobic training on aerobic and anaerobic parameters using the lactate minimum test (LMT). Sixty-day-old rats were randomly divided into three groups: a baseline group in which rats were evaluated prior to initiation of the study; a control group (Co) in which rats were kept without any treatment during 12 weeks; and a chronic exercise group (Tr) in which rats swam for 40 min/day, 5 days/week at 80% of anaerobic threshold during 12 weeks. After the experimental period, SPA of rats was measured using a gravimetric method. Rats had their expression of MCTs determined by RT-PCR analysis. In essence, aerobic training is effective in maintaining SPA, but did not prevent the decline of aerobic capacity and anaerobic performance, leading us to propose that the decline of SPA is not fully attributed to a deterioration of physical properties. Changes in SPA were concomitant with changes in MCT1 expression in the soleus muscle of trained rats, suggestive of an additional adaptive response toward increased lactate clearance. This result is in line with our observation showing a better equilibrium on lactate production-remotion during the continuous exercise (LMT). We propose an approach to combat the decline of SPA of rats in their home cages. This new finding is worth for scientists who work with animal models to study the protective effects of exercise.

Short and Long Term Effects of High-Intensity Interval Training on Hormones, Metabolites, Antioxidant System, Glycogen Concentration, and Aerobic Performance Adaptations in Rats

“…While the endurance protocols attenuated the natural loss of aerobic capacity, the HIIT long term increased significantly. Scariot et al (2016) reported that aerobic training is effective to attenuate the decrease in spontaneous physical activity, but did not prevent the decline of aerobic performance. This result was attributed to small cages of confinement of laboratory rats.…”

Spontaneous Physical Activity Defends Against Obesity

“…Recent evidence has explored whether other traits related to energy balance and physical activity are correlated with or influence SPA. For example, aerobic capacity does not correlate with SPA [56] while basal metabolic rate does [57], and the evidence is still mixed as to the effects of voluntary exercise on SPA [58–61]. Future challenges include the accurate measurement of SPA, its different components and NEAT, the possibility of measuring SPA and NEAT in group housed animals, and accurate comparison of the physiological effects and mechanisms of SPA between males and females.…”

Cardiovascular and Biochemical Responses in Exercise Recuperation in Diabetic Rats

“…All animals were adapted to an aquatic environment to be able to swim during the test, through one daily session of 10 min, for 7 days prior to the experiment. On testing days, the animals performed a 60-min session of predominantly aerobic exercise by carrying an extra weight equivalent to 6% of their body weight in a swimming tank with 40 cm in depth, 70 cm in diameter, and water heated to 30 ± 1°C, according to the protocol proposed by Gobatto et al [13] Post testing, the animals were trained during 30 days by swimming tank, with an extra weight equivalent to 4% extra weight a 40-min session, according to the DOI: http://dx.doi.org /10.5772/intechopen.79084 protocol modified proposed by Scariot et al [14]. Exercise sessions and laboratory procedures were always conducted at the same time of the day (08:00 am).…”