Heat acclimation improves intermittent sprinting in the heat but additional pre-cooling offers no further ergogenic effect

The aim of this study was to determine the effect of 10 days of heat acclimation with and without pre-cooling on intermittent sprint exercise performance in the heat. Eight males completed three intermittent cycling sprint protocols before and after 10 days of heat acclimation. Before acclimation, one sprint protocol was conducted in control conditions (21.8 ± 2.2°C, 42.8 ± 6.7% relative humidity) and two sprint protocols in hot, humid conditions (33.3 ± 0.6°C, 52.2 ± 6.8% relative humidity) in a randomized order. One hot, humid condition was preceded by 20 min of thigh pre-cooling with ice packs (−16.2 ± 4.5°C). After heat acclimation, the two hot, humid sprint protocols were repeated. Before heat acclimation, peak power output declined in the heat (P < 0.05) but pre-cooling prevented this. Ten days of heat acclimation reduced resting rectal temperature from 37.8 ± 0.3°C to 37.4 ± 0.3°C (P < 0.01). When acclimated, peak power output increased by 2% (P < 0.05, main effect) and no reductions in individual sprint peak power output were observed. Additional pre-cooling offered no further ergogenic effect. Unacclimated athletes competing in the heat should pre-cool to prevent reductions in peak power output, but heat acclimate for an increased peak power output

Intermittent exercise with and without hypoxia improves insulin sensitivity in individuals with type 2 diabetes

Context: Hypoxia and muscle contraction stimulate glucose transport activity in vitro. Exercise and hypoxia have additive effects on insulin sensitivity in type 2 diabetics (T2D). Objective: The objective of the study was to examine the effectiveness of intermittent exercise with and without hypoxia on acute- and moderate-term glucose kinetics and insulin sensitivity in T2D. Setting: The study was conducted at a university research center. Design, Participants, and Interventions: Eight male T2D patients completed the following: 1) 60 min of continuous exercise at 90% lactate threshold in hypoxia (HyEx60); 2) intermittent exercise at 120% lactate threshold, separated by periods of passive recovery (5:5 min) in hypoxia [Hy5:5; O2 ∼ 14.7 (0.2)%]; and 3) intermittent exercise (5:5 min) at 120% lactate threshold in normoxia (O2 ∼ 20.93%). Main Outcome Measures: Glucose appearance and glucose disappearance, using an adapted non-steady-state one-compartment model were measured. Homeostasis models of insulin resistance (HOMAIR), fasting insulin resistance index (FIRI), and β-cell function were calculated 24 and 48 h after exercise conditions. Results: Glucose disappearance increased from baseline (1.85 mg/kg · min−1) compared with 24 h (2.01 min/kg · min−1) after HyEx60 (P = 0.031). No difference was noted for both Hy5:5 (P = 0.064) and normoxia (P = 0.385). Hy5:5 demonstrated improvements in HOMAIR from baseline [d 1, 6.20 (0.40)] when comparisons were made with d 2 [4.83 (0.41)] (P = 0.0013). HOMAIR and FIRI improved in the 24 h (HOMAIR, P = 0.002; FIRI, P = 0.003), remaining reduced 48 h after HyEx60 (HOMAIR, P = 0.028; and FIRI, P = 0.034). Conclusion: HyEx60 offered the greatest improvements in acute and moderate-term glucose control in T2D. Intermittent exercise stimulated glucose disposal and improved after exercise insulin resistance, which was enhanced when exercise was combined with hypoxia (Hy5:5). The data suggest a use of hypoxic exercise in treatment of T2D

External shocks and unemployment in a dual labour market model

SIGLEAvailable from British Library Document Supply Centre-DSC:3597.9178(no 99/10) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Urbanization, rural-urban migration and policy

Paper commissioned by UNESCOSIGLEAvailable from British Library Document Supply Centre-DSC:3597.9178(no 2001/3) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

The economics of development A review article

Available from British Library Document Supply Centre-DSC:3597.918(no 95/1) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Socio-economic determinants of early childhood mortality A study of three Indian states

SIGLEAvailable from British Library Document Supply Centre-DSC:3597.918(no 98/2) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Migration, employment and development A three-sector analysis

SIGLEAvailable from British Library Document Supply Centre-DSC:3597.918(no 98/1) / BLDSC - British Library Document Supply CentreGBUnited Kingdo