RESUMO

Spirulina platensis has shown effectiveness in the treatment of allergic rhinitis in rats, but its action in tracheal reactivity or on markers of relaxation and antioxidant profile has not yet been possible to determine. In this paper, the animals were divided into the groups healthy (SG) and supplemented with S. platensis at doses of 50 (SG50), 150 (SG150), and 500 mg/kg (SG500). We also evaluated nitrite levels, lipid peroxidation, and antioxidant activity through biochemical analysis. For contractile reactivity, only SG500 (pEC50 = 5.2 ± 0.06 showed reduction in carbachol contractile potency. Indomethacin caused a higher contractile response to carbachol in SG150 and SG500. For relaxation, curves for SG150 (pEC50 = 5.0 ± 0.05) and SG500 (pEC50 = 7:3 ± 0:02) were shifted to the left, more so in SG500. We observed an increase in nitrite in the trachea only with supplementation of 500 mg/kg (54.0 ± 8.0 µM), also when compared to SG50 (37.0 ± 10.0 µM) and SG150 (38.0 ± 7.0 µM). We observed a decrease in lipid peroxidation in the plasma and an increase in oxidation inhibition for the trachea and lung in SG150 and SG500, suggesting enhanced antioxidant activity. S. platensis (150/500 mg/kg) decreased the contractile response and increased relaxation by increasing antioxidant activity and nitrite levels and modulating the inflammatory response.

RESUMO

This study identifies physical activity (PA) and sedentary behaviour (SB) clusters in preschoolers compliant (C) or non-compliant (NC) with sleep recommendations; and associates these clusters with obesity markers. PA and SB were objectively assessed (Actigraph WGT3-X) in 272 preschoolers (4.4 ± 0.7 years old). Sleep duration was parent-reported, and preschoolers were classified as C (3-4 years old: 600-780 min/day; 5 years old: 540-660 min/day) or NC with sleep recommendations. Body mass index (BMI) and waist circumference (WC) were assessed according to international protocols. Moderate to vigorous physical activity (MVPA) and light physical activity (LPA) were categorized as low/high (<60 min/>60 min/day or <180 min/180 min/day, respectively). SB was defined according to mean values between clusters. Latent profile analysis was performed. Associations between the observed clusters and obesity markers were determined using linear regression (RStudio; 1.3.1073). Four cluster solutions for C and NC preschoolers were identified. A negative association between C/Low MVPA cluster and BMI, and a positive association between NC/Low MVPA and BMI (ß = -0.8, 95%CI = -1.6;-0.1, and ß = 0.9, 95%CI = 0.1;1.7, respectively) were observed. No association was seen for SB clusters. Adequate sleep duration may have a protective role for preschoolers' BMI, even if the children do not comply with MVPA recommendations.

Assuntos

Obesidade , Comportamento Sedentário , Índice de Massa Corporal , Criança , Pré-Escolar , Humanos , Obesidade/epidemiologia , Sono , Circunferência da Cintura

RESUMO

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.

RESUMO

The reduction in blood pressure after the physical exercise practice is called postexercise hypotension (PEH). Previous studies have demonstrated that the ingestion of caffeine at levels corresponding to three doses of coffee eliminates this phenomenon. Thus, we evaluated the influence of different doses of coffee in the PEH in twelve hypertensives, who performed four experimental sessions of aerobic exercise on a cycle ergometer (lasting 40 minutes, with intensity between 60% and 80% of maximum heart rate), followed by the ingestion of one (CAF-1), two (CAF-2), or three (CAF-3) doses of caffeinated coffee, or three doses of decaffeinated coffee (DESC). The blood pressure was measured at rest and at 10-minute intervals during 120 minutes of recovery post exercise. DESC resulted in systolic PEH at all moments of measurement, with averages of -4.1±1.2 mmHg and -1.8±1.3 mmHg on the 1st and 2nd hours post exercise, respectively. In CAF-1, both systolic hypotensive and hypertensive responses to the exercise were identified, with averages of -1.2±1.7 and 0.5±0.4 mmHg after one and two hours of recovery. Conversely, hypertensive systolic response occurred in all measurements compared rest blood pressure. The 1st and 2nd hours post exercise was 4.5±1.1 and 6.5+1.1 mmHg in CAF-2 and 5.1+0.9 and 6.5+1.0 mmHg to CAF-3. Diastolic PEH was not found in any of the experimental sessions. Therefore, the ingestion of two and three doses of caffeinated coffee completely blunts the PEH, while one dose results in partial elimination of the PEH.