Inflammatory response of the peripheral neuroendocrine system following downhill running

Exploring the relationship between exercise inflammation and the peripheral neuroendocrine system is essential for understanding how acute or repetitive bouts of exercise can contribute to skeletal muscle adaption. In severe damage, some evidence demonstrates that peripheral neuroendocrine receptors might contribute to inflammatory resolution, supporting the muscle healing process through myogenesis. In this sense, the current study aimed to evaluate two classic peripheral neuronal receptors along with skeletal muscle inflammation and adaptation parameters in triceps brachii after exercise. We euthanized C57BL (10 to 12 weeks old) male mice before, and one, two, and three days after a downhill running protocol. The positive Ly6C cells, along with interleukin-6 (IL-6), nuclear factor kappa B (NF-κB), glucocorticoid receptor (GR), α7 subunits of the nicotinic acetylcholine receptor (nAChRs), and myonuclei accretion were analyzed. Our main results demonstrated that nAChRs increased with the inflammatory and myonuclei accretion responses regardless of NF-κB and GR protein expression. These results indicate that increased nAChR may contribute to skeletal muscle adaption after downhill running in mice.

Emotional eating, binge eating, physical inactivity, and vespertine chronotype are negative predictors of dietary practices during COVID-19 social isolation: A cross-sectional study

Objectives

Coronavirus disease 2019 (COVID-19) emerged and rapidly spread worldwide. Several countries have imposed lockdown and isolation in attempt to mitigate viral spread. However, social isolation has a negative effect on psychological aspects, increasing stress, fear, anxiety, anger and emotional disturbance, as well as affecting sleep pattern and the practice of physical activity. Negative emotions and lifestyle changes trigger overeating, consequently affecting dietary practices. The aim of this study was to verify the prevalence of lifestyle factors (i.e., sleep time/quality and practice of physical exercise), eating behavior dimensions, chronotype, and association with dietary practices (planning, domestic organization, food choice, ways of eating) in home confinement during the COVID-19 pandemic in São Paulo, Brazil.

Methods

This cross-sectional study was conducted between April 27 and May 25, 2020. An anonymous online questionnaire (Microsoft Forms) was used for data collection by the snowball method. We verified dietary practices (outcome), eating behavior, physical exercise practice, sleep quality and duration, and chronotype (exposure variables). Sex, age, educational and social status were assessed as covariates and confounders. We evaluated 724 adults (585 women and 139 men). Mean age was 32.6 y (±11.3) for women and 33.5 y (±10.5) for men.

Results

Emotional eating (EE) and binge eating (BE) were positively correlated (r = 0.66; P <0.001). Dietary practices were negatively correlated with BE (r = –0.41; P <0.001), EE (r = –0.33; P <0.001) and body mass index (r = –0.24; P <0.001). Linear regression demonstrated that EE (β = –0.1351; t = –2.841; P = 0.005; η_p² = 0.013), BE (β = –0.2580; t = –5.612; P < 0.001; η_p² = 0.050), no practice of physical exercise at home (β = –0.4271; t = –5.933; P < 0.001; η_p² = 0.055), being vespertine (β = –0.3435; t = 2.076; P = 0.038; η_p² = 0.019), and age (β = –0.082; t = –2.210; P = 0.027; η_p² = 0.008) are negative predictors of dietary practices. Finally, cognitive restraint (β = 0.1407; t = 3.858; P < 0.001; η_p² = 0.024), better sleep quality (β = 0.1768; t = 2.506; P = 0.012; η_p² = 0.010), receiving 4–10 wages per month (according to a minimum wage in Brazil that corresponds to US $ 183.01) (β = 0.2568; t = 2.573; P = 0.10; η_p² = 0.027) and 10 – 20 wages per month (β = 0.4490; t = 3.726; P < 0.001; η_p² = 0.027) are positive predictors of dietary practices.

Conclusion

Eating behavior, physical exercise, sleep, and social factors can be important predictors for dietary practices during COVID-19 social confinement. Longitudinal studies in Brazil are needed to confirm these findings.

Exercise deprivation increases negative mood in exercise-addicted subjects and modifies their biochemical markers

The aim of this study was to identify the possible association between biochemical markers of exercise addiction and affective parameters in a sample of athletes during 2weeks of withdrawal exercise. Eighteen male runners were distributed into a control group (n=10) composed of runners without exercise addiction symptoms and an exercise addiction group (n=8) composed of runners with exercise addiction symptoms. The volunteers performed a baseline evaluation that included affective questionnaires, blood samples, body composition and an aerobic test performed at ventilatory threshold I. After the baseline evaluation, the groups started an exercise withdrawal period that was sustained for 2weeks. During exercise withdrawal, an actigraph accelerometer was used to monitor the movement index, and CK and LDH were measured in blood samples to validate the non-exercise practice. At the end of the exercise withdrawal period, a blood collection, aerobic test and mood scale was performed in the re-test. The results showed that at the end of the experimental protocol, when compared with the control group, the exercise addiction group showed an increase in depression, confusion, anger, fatigue and decreased vigor mood that improved post-exercise, along with low levels of anandamide at all time-points evaluated and a modest increase in β-endorphin post-exercise. Moreover, the exercise addiction group showed a decrease in oxygen consumption and respiratory exchange ratio after the exercise withdrawal period, which characterized a detraining phenomenon. Our data suggest that a 2-week withdrawal exercise period resulted in an increase of negative mood in exercise addiction; additionally, exercise addiction showed low levels of anandamide.

Downhill exercise-induced changes in gene expression related with macrophage polarization and myogenic cells in the triceps long head of rats

Macrophages are one of the most heterogenic immune cells involved in skeletal muscle regeneration. After skeletal muscle damage, M1 phenotypes exhibit pro-inflammatory reaction. In a later stage, they are converted to M2 phenotypes with anti-inflammatory properties. To study when gene expressions of macrophage polarization are changed after damage induced by downhill exercise to exhaustion is the objective of this paper. Before (CTRL) and 0 h (G0), 24 h (G24), 48 h (G48) and 72 h (G72) after 18 bouts of downhill exercise, the animals were euthanised, and the triceps were dissected. We measured gene expression of macrophages (CD68 and CD163), myogenic cells (MyoD and myogenin) and quantified cytokine secretion (interleukin (IL)-6, IL-10 and tumour necrosis factor alpha (TNF-α)). The CD68 expression was lower in G72 compared with G24 (P = 0.005) while CD163 was higher in G48 compared with G24 (P = 0.04). The MyoD expression was higher in G72 compared with G0 (P = 0.04). The myogenin expression was lower in G24 compared with CTRL (P = 0.01) and restored in G72 compared with G24 (P = 0.007). The TNF-α was significantly higher at all times after 24 h (all compared with CTRL, with P = 0.03). The CD68 and CD163 expressions behaved distinctly after exercise, which indicates macrophage polarization between 24 and 48 h. The distinct expression of myogenin, concomitantly with MyoD elevation in G72, indicates that myogenic cell differentiation and the significant change of TNF-α level show an important role of this cytokine in these processes.