Increasing nitric oxide bioavailability via supplementation with nitrate-rich beetroot juice (BR) has been shown to attenuate the negative effect of hypoxia on peripheral oxygen saturation and exercise tolerance. We investigated the effects of a single dose of concentrated BR on the physiological responses to submaximal exercise and time trial (TT) performance in trained cyclists exposed to moderate simulated altitude (approximately 2500 m). Nine competitive amateur male cyclists (age, 28 ± 8 yr; V˙O2peak at altitude, 51.9 ± 5.8 mL·kg·min) completed four exercise trials consisting of an initial graded test to exhaustion and three performance trials on a cycle ergometer. The performance trials comprised 15 min of submaximal steady-state exercise at 60% maximum work rate and a 16.1-km TT. The second and third trials were preceded by ingestion of either 70 mL of BR or nitrate-depleted BR (PLA) 3 h before exercise. Plasma nitrate (PLA, 39.1 ± 3.5 µM; BR, 150.5 ± 9.3 µM) and nitrite (PLA, 289.8 ± 27.9 nM; BR, 678.1 ± 103.5 nM) measured immediately before exercise were higher after ingestion of BR compared with that after PLA (P < 0.001, P = 0.004). V˙O2 during steady-state exercise was lower in the BR trial (2542 ± 114 mL·min) than that in the PLA trial (2727 ± 85 mL·min, P = 0.049). TT performance was significantly faster after BR (1664 ± 14 s) than that after PLA (1702 ± 15 s, P = 0.021). A single dose of BR lowered V˙O2 during submaximal exercise and enhanced TT performance of trained cyclists in normobaric hypoxia. Consequently, ingestion of BR may be a practical and effective ergogenic aid for endurance exercise at altitude.

The aim of the current study was to determine the effects of dietary nitrate ingestion on parameters of submaximal and supramaximal exercise and time trial (TT) performance in trained kayakers. Eight male kayakers completed four exercise trials consisting of an initial discontinuous graded exercise test to exhaustion and three performance trials using a kayak ergometer. The performance trials were composed of 15 min of paddling at 60% of maximum work rate, five 10-s all-out sprints, and a 1 km TT. The second and third trials were preceded by ingestion of either 70 ml nitrate-rich concentrated beetroot juice (BR) or tomato juice (placebo [PLA]) 3 hr before exercise using a randomized crossover design. Plasma nitrate (PLA: 33.8 ± 1.9 μM, BR: 152 ± 3.5 μM) and nitrite (PLA: 519.8 ± 25.8, BR: 687.9 ± 20 nM) were higher following ingestion of BR compared with PLA (both p < .001). VO₂ during steady-state exercise was lower in the BR trial than in the PLA trial (p = .010). There was no difference in either peak power in the sprints (p = .590) or TT performance between conditions (PLA: 277 ± 5 s, BR: 276 ± 5 s, p = .539). Despite a reduction in VO₂, BR ingestion appears to have no effect on repeated supramaximal sprint or 1 km TT kayaking performance. A smaller elevation in plasma nitrite following a single dose of nitrate and the individual variability in this response may partly account for these findings.

Metabolomic profiling of nine trained ultramarathon runners completing an 80.5 km self-paced treadmill-based time trial was carried out. Plasma samples were obtained from venous whole blood, collected at rest and on completion of the distance (post-80.5 km). The samples were analyzed by using high-resolution mass spectrometry in combination with both hydrophilic interaction (HILIC) and reversed phase (RP) chromatography. The extracted putatively identified features were modeled using Simca P 14.1 software (Umetrics, Umea, Sweden). A large number of amino acids decreased post-80.5 km and fatty acid metabolism was affected with an increase in the formation of medium-chain unsaturated and partially oxidized fatty acids and conjugates of fatty acids with carnitines. A possible explanation for the complex pattern of medium-chain and oxidized fatty acids formed is that the prolonged exercise provoked the proliferation of peroxisomes. The peroxisomes may provide a readily utilizable form of energy through formation of acetyl carnitine and other acyl carnitines for export to mitochondria in the muscles; and secondly may serve to regulate the levels of oxidized metabolites of long-chain fatty acids. This is the first study to provide evidence of the metabolic profile in response to prolonged ultramarathon running using an untargeted approach. The findings provide an insight to the effects of ultramarathon running on the metabolic specificities and alterations that may demonstrate cardio-protective effects.

This study investigated the stability of the measurement of respiratory variables during rest, walking and running using the K4b² portable metabolic analyser in ten active males (age 31 ± 11 years; peak 42.1 ± 2.6 ml · min⁻¹ · kg⁻¹). Following a 10 min rest, participants completed three discontinuous incremental exercise tests on a treadmill while walking (4, 5 and 6 km · h⁻¹) and running (8, 10, 12, 14 and 16 km · h⁻¹, or until volitional exhaustion). Participants completed 3 min of exercise at each speed, followed by a 3 min recovery after each stage above 10 km · h⁻¹. The respiratory variables were measured using either a laboratory-based metabolic cart as a reference method (Oxycon Pro, OP), a K4b² calibrated immediately before the test (K4b²), or a K4b² calibrated 1 h before the test (K4b²DEL). Compared to the OP, carbon dioxide production ( ) and were not different when measured by K4b² or K4b²DEL. There was no difference in between OP and K4b² tests (P = 0.19, mean difference = 38 ml · min⁻¹ and limits of agreement (LOA) = 208 to –285) although K4b²DEL overestimated (P = 0.05, mean difference = 84 ml · min⁻¹ and LOA = 302 to –469). These data suggest that a drift in measurement accuracy appears to cause the K4b² to overestimate in tests lasting longer than 1 h.

Ethanol is the most commonly encountered drug in forensic toxicology, with widespread use throughout society. For this reason, it is important that there are a variety of reliable and robust methods to detect and quantify the content of alcohol in blood samples of suspected drink drivers. A common method of detection is gas chromatography with flame ionisation detector, with a number of sample preparation techniques employed. Typically, venous blood is sampled and used in the analysis. However, there is currently no legal specification in the UK of the blood sample source. This study investigates the use of capillary blood as an alternative to venous blood alongside two different sample volumes: 100 and 10 µL. Venous and capillary blood were collected from volunteers who had consumed alcohol. All blood sampling was carried out one hour after cessation of drinking. The results show a statistically significant difference between venous and capillary samples, with an average difference of 3.38 ± 1.99 mg/100 mL at 100 μL and approximately 4.13 ± 2.42 mg/100 mL at 10 μL, respectively. Predominantly, venous blood was detected at higher concentrations than the corresponding capillary samples. The deviations in alcohol samples between venous and capillary blood are consistent with previous studies. However, our research indicates that capillary blood is a viable matrix to test for alcohol, albeit one that underestimates blood-alcohol content in relation to venous sampling. There was no statistically significant difference between the 100 and 10 µL sample preparation methods on an individual basis, which infers that micro-volumes of alcohol are suitable for forensic blood-alcohol analysis.