The influence of the site of sampling and assay medium upon the measurement and interpretation of blood lactate responses to exercise.

This paper reports the findings of two investigations into methodological problems associated with the interpretation of blood lactate (BLa) in the sports sciences. In Experiment 1, brachial artery (A), antecubital venous (V) and fingertip capillary (C) blood samples were drawn simultaneously from nine subjects (mean age 21.1 +/- 1.3 years) during an incremental treadmill protocol and immediately assayed for BLa concentration. Experiment 2 investigated the extent of lactate concentration differences in whole blood (WB), lysed blood (LB) and plasma (P) measured using a YSI 23 AM analyser. In Experiment 1, a comparison of the mean BLa concentrations obtained from the three sites revealed no significant differences (P greater than 0.05). Correlations between BLa samples from different sites were very high, with r values ranging from 0.858 to 0.983. In Experiment 2, the mean lactate concentrations were: WB, 4.7 +/- 2.7 mM; LB, 5.0 +/- 3.0 mM; P, 7.0 +/- 3.8 mM. Plasma (P) values were significantly higher than WB and LB. Values from all sites were highly correlated with coefficients ranging from 0.963 to 0.987. In conclusion: (1) Significant arterial and venous BLa concentration differences do not exist during incremental treadmill exercise. (2) As capillary BLa concentrations reflect arterial values, their use in laboratory and field settings is recommended. (3) Lactate concentration differences in whole blood, lysed blood and plasma will influence the assessment of performance at fixed lactate reference values. (4) If the inter-laboratory test procedures are to be standardized and results compared, precise reporting of lactate sampling and assay techniques is critical.     

Fluid and electrolyte needs for preparation and recovery from training and competition

For a person undertaking regular exercise, any fluid deficit that is incurred during one exercise session can potentially compromise the next exercise session if adequate fluid replacement does not occur. Fluid replacement after exercise can, therefore, frequently be thought of as hydration before the next exercise bout. The importance of ensuring euhydration before exercise and the potential benefits of temporary hyperhydration with sodium salts or glycerol solutions are also important issues. Post-exercise restoration of fluid balance after sweat-induced dehydration avoids the detrimental effects of a body water deficit on physiological function and subsequent exercise performance. For effective restoration of fluid balance, the consumption of a volume of fluid in excess of the sweat loss and replacement of electrolyte, particularly sodium, losses are essential. Intravenous fluid replacement after exercise has been investigated to a lesser extent and its role for fluid replacement in the dehydrated but otherwise well athlete remains equivocal.     

Use of libraries and electronic information resources by primary care staff: outcomes from a survey

OBJECTIVES: To assess the use of existing libraries; usage of the Internet and biomedical databases; and need for training on use of the Internet and biomedical databases for primary care staff. METHODS: A postal survey of general practitioners (GPs), practice nurses (PNs) and practice managers (PMs) in Nottingham and Rotherham, UK. RESULTS: Overall, 243 questionnaires were used. The response rate in Nottingham was 24%, in Rotherham it was 34%. Reported use of libraries was low (30%), with PNs reporting significantly higher usage (65%) than others (P < 0.01). Most respondents reported using the Internet (81%), but fewer (44%) reported using databases. GPs and PNs were significantly more likely to report using databases than PMs (P < 0.01). Lack of training was the most reported barrier to using the Internet (67%) and databases (52%). Overall, 52% of respondents reported wanting Internet training, 64% wanted database training. The percentages requesting training on databases were high among GPs and PNs, but significantly lower for PMs (P = 0.02). CONCLUSIONS: There are differences in the usage of libraries and electronic resources among the primary care team, and in reported training needs. While the reported levels of usage of the Internet and biomedical databases are encouraging, our study identified a training need. If met, this could increase usage further.