Exercising Fasting or Fed to Enhance Fat Loss? Influence of Food Intake on Respiratory Ratio and Excess Postexercise Oxygen Consumption After a Bout of Endurance Training

Exercise and nutrition are often used in combination to lose body fat and reduce weight. In this respect, exercise programs are as important as correct nutrition. Several issues are still controversial in this field, and among them there are contrasting reports on whether training in a fasting condition can enhance weight loss by stimulating lipolytic activity. The authors' purpose was to verify differences in fat metabolism during training in fasting or feeding conditions. They compared the effect on oxygen consumption (VO2) and substrate utilization, estimated by the respiratory-exchange ratio (RER), in 8 healthy young men who performed the same moderate-intensity training session (36 min of cardiovascular training on treadmill at 65% maximum heart rate) in the morning in 2 tests in random sequence: FST test (fasting condition) without any food intake or FED test (feeding condition) after breakfast. In both cases, the same total amount and quality of food was assumed in the 24 hr after the training session. The breakfast, per se, increased both VO2 and RER significantly (4.21 vs. 3.74 and 0.96 vs. 0.84, respectively). Twelve hours after the training session, VO2 was still higher in the FED test, whereas RER was significantly lower in the FED test, indicating greater lipid utilization. The difference was still significant 24 hr after exercise. The authors conclude that when moderate endurance exercise is done to lose body fat, fasting before exercise does not enhance lipid utilization; rather, physical activity after a light meal is advisabl

Meccanismi fisiologici e strumentali di protezione del rachide durante la pratica del Fitness

La protezione del rachide durante l’esecuzione di esercizi con sovraccarichi nella pratica del Fitness, al di là di ovvie e banali raccomandazioni, sull’entità del carico e sul mantenimento delle curve fisiologiche, spesso non viene adeguatamente sottolineata. Ancor meno vengono evidenziate le implicazioni della respirazione e del meccanismo della cosìdetta IAP (Intra Abdominal Pressure) sulla protezione del rachide sotto carico e durante esercizio. In questa review vengono analizzati gli studi, compresi quelli basilari e pioneristici di Nachemson, sui meccanismi fisiologici di protezione del rachide da sollecitazioni compressive durante l’esecuzione di esercizi; viene inoltre analizzata l’azione della cintura da sollevamento, “device” spesso usato in maniera non adeguata quando non abusato nei centri Fitness

Exercising fasting or fed to enhance fat loss? Influence of food intake on respiratory ratio and excess postexercise oxygen consumption after a bout of endurance training.

Exercise and nutrition are often used in combination to lose body fat and reduce weight. In this respect, exercise programs are as important as correct nutrition. Several issues are still controversial in this field, and among them there are contrasting reports on whether training in a fasting condition can enhance weight loss by stimulating lipolytic activity. The authors' purpose was to verify differences in fat metabolism during training in fasting or feeding conditions. They compared the effect on oxygen consumption (VO2) and substrate utilization, estimated by the respiratory-exchange ratio (RER), in 8 healthy young men who performed the same moderate-intensity training session (36 min of cardiovascular training on treadmill at 65% maximum heart rate) in the morning in 2 tests in random sequence: FST test (fasting condition) without any food intake or FED test (feeding condition) after breakfast. In both cases, the same total amount and quality of food was assumed in the 24 hr after the training session. The breakfast, per se, increased both VO2 and RER significantly (4.21 vs. 3.74 and 0.96 vs. 0.84, respectively). Twelve hours after the training session, VO2 was still higher in the FED test, whereas RER was significantly lower in the FED test, indicating greater lipid utilization. The difference was still significant 24 hr after exercise. The authors conclude that when moderate endurance exercise is done to lose body fat, fasting before exercise does not enhance lipid utilization; rather, physical activity after a light meal is advisable

PARADOXICAL EFFECT OF RESISTANCE TRAINING AND HIGH PROTEIN DIET ON PLASMA MYOSTATIN RESPONSE TO EXERCISE

Introduction In recent years, a mounting amount of evidence have suggested that contracting muscle can act as a cytokine producing organ that may influence metabolism (Pedersen 2010). Myostatin (MSTN) relationship with body fat amount, training status and nutrition has been widely investigated but with conflicting results. Although MSTN inhibits the Akt/mTor pathway some studies have shown also an counterintuitive positive correlation between MSTN and muscle mass (myostatin paradox). Moreover MSTN has been shown to reduce IGF-1 stimulated AKT phosphorylation in a dose-dependent manner. We investigated the influence of two months of resistance training (RT) and high protein diet on plasma myostatin, IL1, IL6, TNF-• and IGF-1. Methods Eighteen healthy volunteers participated in a upper limbs progressive resistance training. Subjects were divided in two groups: an high protein group (HP; 1.8 g/Kg bw/day, n. 9) and normal protein group (NP 0.9 g/Kg bw-1/day, n. 9). MSTN, IGF-1, IL1, IL6 and TNF-• were analyzed before and after the first training session and before and after the last training session (after 8 weeks). Lean body mass and muscle mass were analyzed through skinfolds methods, arm muscle area with MNR, strength with 1 RM test and an isometric pullgrip. ANOVA statistical analysis and linear regression were performed. Results MSTN showed an unexpected significant increase (p<0.001) after the last training in the HP group ( ng/ml) compared to NP group (ng/ml) and to the samples taken after the first training (ng/ml). There were no significant differences (time x treatment) in IGF- 1, IL1, IL6 and TNF-•. Interestingly IGF-1 showed a positive correlation with MSTN in HP after the last training (r2=0.6456; p=0.0295). No correlation were found with other blood parameters nor with muscle mass and muscle strength changes. Moreover no significant differences were found between treatment group in strength performance and muscle mass. Conclusions Taken together this findings indicate a “paradoxical” response of plasma myostatin to high protein diet after 8 weeks of RT. It is noteworthy that IGF-1 which activity is down regulated by MSNT is increased in HP group after the last training and it correlates significantly with MSNT increase. This double increase of opposite mediators could explain the substantial overlapping of muscle mass increases in the two groups. We can argue that high protein diet influence metabolic regulation of IGF-1 and MSNT upstream the same pathway. Our findings are not in agreement with those of Hulmi et al (2009) that found a decrease in MSNT with protein ingestion whilst instead are in line with those of Dalbo et al (2011) that found a paradoxical MSNT response to RT in older individuals compared to younger individuals. Taken together this data show a complex and not yet well understood MSNT release mechanism. More studies are needed to explain this paradoxical response to nutrition and RT exploring also muscle signalling molecules as mTor and Akt

Effects of high-intensity circuit training, low-intensity circuit training and endurance training on blood pressure and lipoproteins in middle-aged overweight men.

BACKGROUND: The aim of this study was to determine the physiological effects of an high-intensity circuit training (HICT) on several cardiovascular disease risk factors in healthy, overweight middle-aged subjects, and to compare the effects of HICT to traditional endurance training (ET) and low-intensity circuit training (LICT). METHODS: Fifty-eight participants (ages 61±3.3 yrs, BMI 29.8±0.9) were randomly assigned to one of the three exercise treatment groups: HICT, LICT and ET. The three groups exercised three times per week, 50 min per session for 12 weeks. Baseline and after intervention anthropometric characteristics: body weight (BW), fat mass (FM); blood pressure: diastolic (DBP) and systolic (SBP), blood parameters; CHOL-t (total cholesterol), LDL-C (low density lipoprotein-cholesterol), HDL-C (high density lipoprotein-cholesterol), TG (triglycerides), ApoB and ratio ApoB/ApoA1 were measured. RESULTS: Compared to other groups, HICT showed significantly higher reductions in FM, DBP, CHOLt, LDL-C, TG, ApoB and significantly greater increases in high density HDL-C. LICT resulted in the greatest reduction in SBP. All groups showed a significant improvement of BW without any significant differences between groups. CONCLUSIONS: Our findings indicate that high-intensity circuit training is more effective in improving blood pressure, lipoproteins and triglycerides than endurance training alone or lower intensity circuit training