Time to exhaustion at maximal lactate steady state is similar for cycling and running in moderately trained subjects

We compared time to exhaustion (t lim) at maximal lactate steady state (MLSS) between cycling and running, investigated if oxygen consumption, ventilation, blood lactate concentration, and perceived exertion differ between the exercise modes, and established whether MLSS can be determined for cycling and running using the same criteria. MLSS was determined in 15 moderately trained men (30±6years, 77±6kg) by several constant-load tests to exhaustion in cycling and running. Heart rate, oxygen consumption, and ventilation were recorded continuously. Blood lactate concentration and perceived exertion were measured every 5min. t lim (37.7±8.9 vs. 34.4±5.4min) and perceived exertion (7.2±1.7 vs. 7.2±1.5) were similar for cycling and running. Heart rate (165±8 vs. 175±10min−1; P<0.01), oxygen consumption (3.1±0.3 vs. 3.4±0.3lmin−1; P<0.001) and ventilation (93±12 vs. 103±16lmin−1; P<0.01) were lower for cycling compared to running, respectively, whereas blood lactate concentration (5.6±1.7 vs. 4.3±1.3mmoll−1; P<0.05) was higher for cycling. t lim at MLSS is similar for cycling and running, despite absolute differences in heart rate, ventilation, blood lactate concentration, and oxygen consumption. This may be explained by the relatively equal cardiorespiratory demand at MLSS. Additionally, the similar t lim for cycling and running allows the same criteria to be used for determining MLSS in both exercise mode

Cerebral Oximetry Monitoring in Extremely Preterm Infants

BACKGROUND The use of cerebral oximetry monitoring in the care of extremely preterm infants is increasing. However, evidence that its use improves clinical outcomes is lacking. METHODS In this randomized, phase 3 trial conducted at 70 sites in 17 countries, we assigned extremely preterm infants (gestational age, <28 weeks), within 6 hours after birth, to receive treatment guided by cerebral oximetry monitoring for the first 72 hours after birth or to receive usual care. The primary outcome was a composite of death or severe brain injury on cerebral ultrasonography at 36 weeks' postmenstrual age. Serious adverse events that were assessed were death, severe brain injury, bronchopulmonary dysplasia, retinopathy of prematurity, necrotizing enterocolitis, and late-onset sepsis. RESULTS A total of 1601 infants underwent randomization and 1579 (98.6%) were evaluated for the primary outcome. At 36 weeks' postmenstrual age, death or severe brain injury had occurred in 272 of 772 infants (35.2%) in the cerebral oximetry group, as compared with 274 of 807 infants (34.0%) in the usual-care group (relative risk with cerebral oximetry, 1.03; 95% confidence interval, 0.90 to 1.18; P = 0.64). The incidence of serious adverse events did not differ between the two groups. CONCLUSIONS In extremely preterm infants, treatment guided by cerebral oximetry monitoring for the first 72 hours after birth was not associated with a lower incidence of death or severe brain injury at 36 weeks' postmenstrual age than usual care. (Funded by the Elsass Foundation and others; SafeBoosC-III ClinicalTrials.gov number, NCT03770741.)