Lipid Oxidation According to Intensity and Exercise Duration in Overweight Men and Women

Abstract

Research Methods and Procedures: Nine young, healthy, overweight men and women were studied (age, 31.4 Ϯ 2.3 and 26.7 Ϯ 2.1 years; BMI, 27.9 Ϯ 0.4 and 27.2 Ϯ 0.5; for men and women, respectively). On one study day, the subjects first performed 30 minutes of cycling exercise at 30% of their maximal oxygen uptake (VO 2max ; E1 session), followed by 30 minutes of exercise at 50% VO 2max (E2 session). On a second study day, a similar E1 session was followed by 30 minutes of exercise at 70% VO 2max (E3 session). From the gas exchange measurements, the respiratory exchange ratio (RER) and the fat oxidation rate (FOR) were calculated. Plasma concentrations of glycerol and non-esterified fatty acids (NEFAs) were assayed. Results: RER was significantly lower for women during only the E1 session. For both sexes, RER decreased over time during the E2 and E3 sessions. During the E1 session, the FOR per kilogram of lean mass (LM) was higher among women, and it did not change over time despite an increase in plasma NEFAs. FOR per kilogram of LM was higher during the E2 exercise for both sexes. During E2 and E3 sessions, as the exercise time was prolonged, the FOR/kg LM increased simultaneously with the increase in the plasma glycerol. Discussion: Lipid oxidation during exercise is optimized for moderate and lengthy exercise. The enhancement of lipid oxidation occurring over time during moderate-and high-intensity exercises could be, in part, linked to the improvement of lipid mobilization. This fact is discussed to shed light on exercise modalities as a tool for the management of overweight.

Does exercise duration affect Fatmax in overweight boys?

“…Based on these results, the authors recommended that a 3 min incremental protocol could be used to provide an estimation of Fat max in this population, but acknowledged that it might not be appropriate for obese children (Zakrzewski and Tolfrey 2011). Furthermore, the exercise duration of 10 min utilised in the constant load bouts may not have been long enough to observe any potential increase in fat oxidation rate over time (Cheneviére et al 2009;Meyer et al 2007;Pillard et al 2007). For these reasons, the primary purpose of the present study was to determine whether Fat max remains stable across 30 min of constant load exercise (i.e., whether the duration of exercise affects fat oxidation rates and ultimately, the Fat max estimate) in overweight boys.…”

“…However, this validation study did not examine whether the rate of fat oxidation changed over time during each continuous exercise bout. This could be important given that fat oxidation rates have been observed to increase as the duration of exercise progresses (Cheneviére et al 2009;Meyer et al 2007;Pillard et al 2007), suggesting that Fat max might also change over time. Furthermore, in the context of graded exercise protocols using consecutive stages to determine Fat max , the increase in the cumulative duration of exercise as the test progresses might affect fat oxidation rates, particularly during the latter stages of the protocol, which may ultimately affect the estimation of Fat max .…”

Comparison between continuous and intermittent submaximal exercise at the intensity of maximal fat oxidation

“…There are a lot of researches to determine the peak fat oxidation rate on individuals with different ages, genders and training situations. It is stated that maximum oxygen consumption on untrained individuals VO2max is 47-52 %, on trained individuals within the range of 59-64% of exercise intensities peak fat oxidation speed was reached (Acthen and Jeukendrup, 2004;Pillard, 2007). Croci et al (2014) reported that peak fat oxidation rate was 46% VO2max in overweight and 45% in lean males.…”

Enerji Kısıtlama Diyeti Yapılmaksızın Uygulanan Aerobik Antrenman Programının Genç Kadın ve Erkeklerin Vücut Kompozisyonu Üzerine Etkileri

“…Egzersiz sürecinde enerji metabolizması inceleyen çalışmalar, egzersiz başlangıcında yağ oksidasyon oranının artığını fakat egzersiz şid-detinin artmasıyla karbonhidrat okasidasyon oranının daha fazla arttığını ortaya koymuştur (9,10). Antrenmansız bireylerde %47-52 VO2maks, antrenmanlı bireylerde %59-64 VO2maks aralığındaki egzersiz yoğunluklarında maksimal yağ oksidasyonuna ulaşıldığı bildirilmektedir (11,12). Bundan dolayı vücut yağının azaltılmasıyla ilgili çalışmalarda sıklıkla orta yoğunlukta yapılan yürüyüş, (13) koşu, (14) ve bisiklet (15) aerobik egzersiz programları uygulanmaktadır.…”