The Impact of Decaffeinated Green Tea Extract on Fat Oxidation, Body Composition and Cardio-Metabolic Health in Overweight, Recreationally Active Individuals.

This study investigated the effect of decaffeinated green tea extract (dGTE), with or without antioxidant nutrients, on fat oxidation, body composition and cardio-metabolic health measures in overweight individuals engaged in regular exercise. Twenty-seven participants (20 females, 7 males; body mass: 77.5 ± 10.5 kg; body mass index: 27.4 ± 3.0 kg·m2; peak oxygen uptake (O2peak): 30.2 ± 5.8 mL·kg-1·min-1) were randomly assigned, in a double-blinded manner, either: dGTE (400 mg·d-1 (-)-epigallocatechin-3-gallate (EGCG), n = 9); a novel dGTE+ (400 mg·d-1 EGCG, quercetin (50 mg·d-1) and α-lipoic acid (LA, 150 mg·d-1), n = 9); or placebo (PL, n = 9) for 8 weeks, whilst maintaining standardised, aerobic exercise. Fat oxidation ('FATMAX' and steady state exercise protocols), body composition, cardio-metabolic and blood measures (serum glucose, insulin, leptin, adiponectin, glycerol, free fatty acids, total cholesterol, high [HDL-c] and low-density lipoprotein cholesterol [LDL-c], triglycerides, liver enzymes and bilirubin) were assessed at baseline, week 4 and 8. Following 8 weeks of dGTE+, maximal fat oxidation (MFO) significantly improved from 154.4 ± 20.6 to 224.6 ± 23.2 mg·min-1 (p = 0.009), along with a 22.5% increase in the exercise intensity at which fat oxidation was deemed negligible (FATMIN; 67.6 ± 3.6%O2peak, p = 0.003). Steady state exercise substrate utilisation also improved for dGTE+ only, with respiratory exchange ratio reducing from 0.94 ± 0.01 at week 4, to 0.89 ± 0.01 at week 8 (p = 0.004). This corresponded with a significant increase in the contribution of fat to energy expenditure for dGTE+ from 21.0 ± 4.1% at week 4, to 34.6 ± 4.7% at week 8 (p = 0.006). LDL-c was also lower (normalised fold change of -0.09 ± 0.06) for dGTE+ by week 8 (p = 0.038). No other significant effects were found in any group. Eight weeks of dGTE+ improved MFO and substrate utilisation during exercise, and lowered LDL-c. However, body composition and cardio-metabolic markers in healthy, overweight individuals who maintained regular physical activity were largely unaffected by dGTE.

Physiological and training characteristics of recreational marathon runners.

PURPOSE: The aim of this study was to examine the physical and training characteristics of recreational marathon runners within finish time bandings (2.5-3 h, 3-3.5 h, 3.5-4 h, 4-4.5 h and >4.5 h). MATERIALS AND METHODS: A total of 97 recreational marathon runners (age 42.4 ± 9.9 years; mass 69.2 ± 11.3 kg; stature 172.8 ± 9.1 cm), with a marathon finish time of 229.1 ± 48.7 min, of whom n = 34 were female and n = 63 were male, completed an incremental treadmill test for the determination of lactate threshold (LT1), lactate turn point (LT2) and running economy (RE). Following a 7-min recovery, they completed a test to volitional exhaustion starting at LT2 for the assessment of [Formula: see text]. In addition, all participants completed a questionnaire gathering information on their current training regimes exploring weekly distances, training frequencies, types of sessions, longest run in a week, with estimations of training speed, and load and volume derived from these data. RESULTS: Training frequency was shown to be significantly greater for the 2.5-3 h group compared to the 3.5-4 h runners (P < 0.001) and >4.5 h group (P = 0.004), while distance per session (km·session-1) was significantly greater for the 2.5-3 h group (16.1 ± 4.2) compared to the 3.5-4 h group (15.5 ± 5.2; P = 0.01) and >4.5 h group (10.3 ± 2.6; P = 0.001). Race speed correlated with LT1 (r = 0.791), LT2 (r = 0.721) and distance per session (r = 0.563). CONCLUSION: The data highlight profound differences for key components of marathon running ([Formula: see text], LT1, LT2, RE and % [Formula: see text]) within a group of recreational runners with the discriminating training variables being training frequency and the absolute training speed.