Interval or continuous aerobic exercise performed 3 days a week increases endothelium-dependent relaxation in female rats fed with fructose

Abstract Aim: We investigated the effects of continuous or interval aerobic exercise training on vascular reactivity of female rats fed with fructose. Methods: Female Wistar rats (8-wk old) were divided into: sedentary (SD), continuous training (CTR), and interval training (ITR). Moderate intensity training protocols consisted of running 3 days/week for 7 weeks. CTR ran 40 min at 30%-40% of the maximal speed (MS) and TRI consisted of 7 sets of 1 min at 70% of MS followed by 3 min at 35% of MS. Animals were fed with standard chow and fructose (10%) in drinking water. Concentration-response curves to acetylcholine and phenylephrine, and oxidative stress biomarkers, were determined in the aorta. Body weight gain, visceral fat, and plasma triglycerides and glucose were also evaluated. Results: Endothelium-dependent relaxation was significantly increased by both exercise regimens (CTR: Emax = 85 ± 6% and ITR: Emax = 84 ± 1%) compared to sedentary rats (SD: Emax = 62 ± 5%). The contractile maximal response was not different but phenylephrine potency was increased in CTR (pEC50: 8.41 ± 0.19) and reduced in ITR (pEC50: 7.06 ± 0.11) compared to SD (pEC50: 7.77 ± 0.08). In addition, the generation of superoxide was lower in trained groups as compared with sedentary (about −28% in CTR and −22% in ITR). TBARS and nitrate/nitrite levels were not modified. Compared to the SD group, ITR gained 39% less body weight and CTR has 29% less visceral fat. Glucose and triglycerides were not modified. Conclusion: CTR and ITR, carried out 3 days/week, were efficient to improve endothelium-dependent relaxation and reduce superoxide generation in the aorta from female rats fed with fructose.

Continuous or interval aerobic exercise training reduces daily fructose intake in female Wistar rat / Exercício físico aeróbio contínuo ou intervalado reduz ingestão de frutose em ratas Wistar

ABSTRACT: Objctive: Fructose consumption has increased worldwide. Excessive fructose intake has been a risk factor for the increased metabolic syndrome disorder incidence. This study aimed to investigate the possible influence of two different exercise training methods, continuous and interval, on fructose intake. Methods: Thirty two-months-old female Wistar rats were divided into six groups: sedentary + water ; sedentary + fructose ; continuous training + water ; interval training + water ; continuous training + fructose ; interval training + fructose . Fructose was given in drinking water (10%). Continuous (40 minutes at 40% maximal speed) or interval training (28 minutes, 1 minute at 70%; 3 minutes at 35% maximal speed) sessions were carried out 3 days/week for 8 weeks. Results: Fructose consumption decreased food intake with a concomitant increase in fluid intake. Continuous and interval training did not modify food intake but progressively reduced fructose ingestion. In the 8th week, interval training + fructose and continuous training + fructose groups drank less fructose solution, 35% and 23%, respectively, than sedentary + fructose group. Conclusion: The findings indicate that both continuous and interval aerobic exercise training seem to modulate food behavior, possibly by mitigating the craving for sweetness, with interval training being more effective in reducing fructose intake than continuous exercise.

RESUMO: Objetivo: O consumo de frutose aumentou em todo o mundo. A ingestão excessiva de frutose tem sido implicada como um fator de risco do aumento da incidência de distúrbios da síndrome metabólica. Nesse contexto, este estudo teve como objetivo investigar a possível influência de dois métodos diferentes de treinamento físico, contínuo e intervalado, na ingestão de frutose. Metodos: Trinta ratas Wistar foram divididas em seis grupos: sedentário + água, sedentário + frutose, treinamento contínuo + água, treinamento intervalado + água, treinamento contínuo + frutose, treinamento intervalado + frutose. A frutose foi dada na água potável (10%). Foram realizadas sessões contínuas (40 minutos a 40% da velocidade máxima) ou intervaladas (28 minutos, 1 minuto a 70%; 3 minutos a 35%) três dias por semana durante oito semanas. Resultados: A ingestão de frutose diminuiu a ingestão alimentar, com um aumento concomitante da ingestão hídrica. O treinamento contínuo e intervalado não modificou a ingestão alimentar, mas reduziu progressivamente a ingestão de frutose. Na oitava semana, treinamento intervalado + frutose e treinamento contínuo + frutose beberam menos solução de frutose, 35% e 23%, respectivamente, do que sedentário + frutose. Conclusão: Os achados indicam que tanto o treinamento aeróbico contínuo quanto o intervalado parecem modular o comportamento alimentar, possivelmente por meio da mitigação do desejo por sabor doce, sendo o treinamento intervalado mais eficaz para reduzir a ingestão de frutose do que o exercício contínuo.