The purpose of this study was to evaluate the effects of Spirulina Platensis supplementation on selected blood markers of oxidative stress, muscle damage, inflammation, and performance in trained rats. Rats (250 g-300 g) were submitted to a strength training program (eight weeks), divided into four groups: control (GT) (trained without supplementation), trained with daily-supplementation of 50 mg/ kg (GT50), 150 mg/kg (GT150) and 500 mg/kg (GT500). Training consisted of a jump protocol in PVCcylinder containing water, with increasing load over experimental weeks. We evaluated the markers of oxidative stress (malondialdehyde-MDA and antioxidant capacity) and inflammation (C-reactive protein) at the end of the training. Among groups submitted to strength training, concentration of C-reactive protein decreased after 8 weeks of intervention in the trained group and GT500. Strength training enhanced plasma MDA concentration of malondialdehyde with supplementation of S. platensis in GT150 and GT500. In plasma analysis, strength training enhanced the percentage of oxidation inhibition, with spirulina supplementation in rates of 150 and 500 mg/kg. Spirulina supplementation for 8 weeks (in a dose-effect manner) improved antioxidant capacity as well as attenuated exercise-induced increases in ROS and inflammation. As a practical application, the use as high doses did not cause a reduction in positive physiological adaptations to exercise training. Additional studies are necessary to test the application of Spirulina Platensis in other contexts, as collective sports (basketball, football, soccer). Spirulina platensis is a microalga with biological activity as antioxidant, immunomodulatory, and anti-inflammatory and nowadays is used to produce nutritional supplements 1-3. S. platensis is composed of protein (55%-70%) 4 , carbohydrates (15%-20%) 5 , lipids (approximately 7%) 5 , fiber, ash, and water including various minerals, vitamins, γ-linolenic acid, chlorophyll, carotenoids, and phycocyanin 2,6. Recently, some researchers have reported that the latter played a crucial role in the antioxidative action of S. platensis 2 .
Objective: To evaluate the accuracy of the smartphone application (app) HRV Expert (CardioMood) and a chest strap (H10 Polar) for recording R-R intervals compared with electrocardiogram (ECG). Methods: A total of 31 male recreational runners (age 36.1 [6.3] y) volunteered for this study. R-R intervals were recorded simultaneously by the smartphone app and ECG for 5 minutes to analyze heart-rate variability in both the supine and sitting positions. Time-domain indexes (heart rate, mean R-R, SD of RR intervals, count of successive normal R-R intervals differing by more than 50 ms, percentage of successive normal R-R intervals differing by more than 50 ms, and root mean square of successive differences between normal R-R intervals), frequency-domain indexes (low frequency, normalized low frequency, high frequency, normalized high frequency, low-frequency to high-frequency ratio, and very low frequency), and nonlinear indexes (SD of instantaneous beat-to-beat variability and long-term SD of continuous R-R intervals) were compared by unpaired t test, Pearson correlation, simple linear regression, and Bland–Altman plot to evaluate the agreement between the devices. Results: High similarity with P value varying between .97 and 1.0 in both positions was found. The correlation coefficient of the heart-rate-variability indexes was perfect (r = 1.0; P = .00) for all variables. The constant error, standard error of estimation, and limits of agreement between ECG and the smartphone app were considered small. Conclusion: The smartphone app and chest strap provide excellent ECG compliance for all variables in the time domain, frequency domain, and nonlinear indexes, regardless of the assessed position. Therefore, the smartphone app replaces ECG for any heart-rate-variability analysis in runners.
The possible mechanism is involved in the effects of Spirulina platensis on vascular reactivity. Animals were divided into sedentary group (SG) and sedentary groups supplemented with S. platensis at doses of 50 (SG50), 150 (SG150), and 500 mg/kg (SG500). To evaluate reactivity, cumulative concentration-response curves were constructed for phenylephrine and acetylcholine. To evaluate the involvement of the nitric oxide (NO) pathway, aorta tissue was preincubated with L-NAME and a new curve was then obtained for phenylephrine. Biochemical analyses were performed to evaluate nitrite levels, lipid peroxidation, and antioxidant activity. To contractile reactivity, only SG500 (pD2 = 5.6 ± 0.04 vs. 6.1 ± 0.06, 6.2 ± 0.02, and 6.2 ± 0.04) showed reduction in phenylephrine contractile potency. L-NAME caused a higher contractile response to phenylephrine in SG150 and SG500. To relaxation, curves for SG150 (pD2 = 7.0 ± 0.08 vs. 6.4 ± 0.06) and SG500 (pD2 = 7.3 ± 0.02 vs. 6.4 ± 0.06) were shifted to the left, more so in SG500. Nitrite was increased in SG150 and SG500. Lipid peroxidation was reduced, and oxidation inhibition was increased in all supplemented groups, indicating enhanced antioxidant activity. Chronic supplementation with S. platensis (150/500 mg/kg) caused a decrease in contractile response and increase in relaxation and nitrite levels, indicating greater NO production, due to decreased oxidative stress and increased antioxidant activity.
Studies have shown that supplementation with Spirulina platensis improves vascular reactivity. However, it is unclear whether in association with strength training this effect can be enhanced. Thus, this study aimed to determine the effects of strength training and S. platensis on the reactivity of the aorta from Wistar rat and the possible mechanisms involved. The animals were supplemented with S. platensis and divided into sedentary (SG, SG50, SG150, and SG500) and trained groups (TG, TG50, TG150, and TG500). Nitrite, malondialdehyde (MDA) and antioxidant activity were determined by biochemical assays. To evaluate vascular response, cumulative concentration—response curves to phenylephrine (PHE) and acetylcholine (ACh) were constructed. L-NAME was used to assess the participation of nitric oxide (NO). It was observed that the PHE contractile potency was reduced in TG50, TG150, and TG500 groups compared to SG50, SG150, and SG500 groups, respectively. However, the presence of L-NAME increased the contractile response in all groups. Strength training potentiated the increase in relaxing activity induced by S. platensis, where the pCE50 values of ACh increased in TG150 and TG500. These responses were accompanied by increased nitrite production, MDA reduction and increased antioxidant activity in the aorta of both TG150 and TG500 groups. Thus, the present study demonstrated that combined with strength training, S. platensis potentiates vascular improvement through the participation of NO and reduction of oxidative stress.
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