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The purpose of this experiment was to learn whether low doses of caffeine have ergogenic, perceptual, and metabolic effects during cycling. To determine the effects of 1, 2, and 3 mg/kg caffeine on cycling performance, differentiated ratings of perceived exertion (D-RPE), quadriceps pain intensity, and metabolic responses to cycling exercise, 13 cyclists exercised on a stationary ergometer for 15 min at 80% VO2peak, then, after 4 min of active recovery, completed a 15-min performance ride 60 min after ingesting caffeine or placebo. Work done (kJ/kg) during the performance ride was used as a measure of performance. D-RPE, pain ratings, and expired-gas data were obtained every 3 min, and blood lactate concentrations were obtained at 15 and 30 min. Compared with placebo, caffeine doses of 2 and 3 mg/kg increased performance by 4% (95% CI: 1.0-6.8%, p = .02) and 3% (95% CI: -0.4% to 6.8%, p = .077), respectively. These effects were ergogenic, on average, but varied considerably in magnitude among individual cyclists. There were no effects of caffeine on D-RPE or pain throughout the cycling task. Selected metabolic variables were affected by caffeine, consistent with its known actions. The authors conclude that caffeine preparations of 2 and 3 mg/kg enhanced performance, but future work should aim to explain the considerable interindividual variability of the drug's ergogenic properties. [ABSTRACT FROM AUTHOR]

Background: Spinal induced maternal hypotension is a common problem during cesarean delivery. Timing of infusion of crystalloid may be important because of its short stay in intravascular space. Aim: This study was conducted to compare effectiveness of preloading and co-loading with crystalloid in prevention of spinal anesthesia induced maternal hypotension during caesarean section. Material and Methods: In total 62 parturients were randomized to two groups. Preload group (Group P) received 15 ml/kg of Ringer Lactate solution over 20 min before giving low dose (2 ml, 0.5% hyperbaric Bupivacaine) spinal anesthesia and coload group (Group C) were given same volume of Ringer Lactate solution as fast as possible after CSF tapping and Bupivacaine injected. Non-invasive BP measurements were recorded. The incidence of hypotension and dose of inj. Mephentermine were checked. Blood pressure, heart rate, nausea and neonatal outcome were assessed. Results: The incidence of hypotension, blood pressure drop and dose of Mephentermine was lower in the coload group compared to the preload group (significant p<0.05). The incidence of nausea was also lower in the coload group. No significant differences in neonatal outcome. Conclusion: In case of using crystalloids (ringer lactate) for cesarean delivery, coload is more effective than preload for the prevention of maternal hypotension after spinal anesthesia for caesarean delivery. [ABSTRACT FROM AUTHOR]

Very high-intensity, low-volume, sprint interval training (SIT) increases muscle oxidative capacity and may increase maximal oxygen uptake ([Formula: see text]), but whether circulatory function is improved, and whether SIT is feasible in overweight/obese women is unknown. To examine the effects of SIT on [Formula: see text] and circulatory function in sedentary, overweight/obese women. Twenty-eight women with BMI > 25 were randomly assigned to SIT or control (CON) groups. One week before pre-testing, subjects were familarized to [Formula: see text] testing and the workload that elicited 50% [Formula: see text] was calculated. Pre- and post-intervention, circulatory function was measured at 50% of the pre-intervention [Formula: see text], and a GXT was performed to determine [Formula: see text]. During the intervention, SIT training was given for 3 days/week for 4 weeks. Training consisted of 4-7, 30-s sprints on a stationary cycle (5% body mass as resistance) with 4 min active recovery between sprints. CON maintained baseline physical activity. Post-intervention, heart rate (HR) was significantly lower and stroke volume (SV) significantly higher in SIT (-8.1 and 11.4%, respectively; P < 0.05) during cycling at 50% [Formula: see text]; changes in CON were not significant (3 and -4%, respectively). Changes in cardiac output ([Formula: see text]) and arteriovenous oxygen content difference [(a - v)O(2) diff] were not significantly different for SIT or CON. The increase in [Formula: see text] by SIT was significantly greater than by CON (12 vs. -1%). Changes by SIT and CON in HR(max) (-1 vs. -1%) were not significantly different. Four weeks of SIT improve circulatory function during submaximal exercise and increases [Formula: see text] in sedentary, overweight/obese women. [ABSTRACT FROM AUTHOR]