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Vasopressin and plasma volume response to submaximal and maximal exercise in man
M S el-Sayed1, B Davies, D B Morgan
1Department of Biological Sciences, University of Salford, UK.
Abstract:
Plasma arginine vasopressin (PAVP), plasma volume loss (PVL) and blood lactic acid (LA) responses to submaximal exercise were examined in 16 normal, healthy individuals. Subjects volunteered to participate in three experiments conducted at the same time of day (9 am) with 7 days intervening between tests. Venous blood was removed before and immediately after 15 min exercise at 40% and 70% VO2max, and before and after 100% VO2max which lasted for 14.3 +/- 1.4 mins (mean +/- SD). The resting mean values of PAVP were similar on the three testing occasions (p greater than 0.05). PAVP rose significantly (p less than 0.05) to all exercise treatments and exhibited an exercise-intensity related response. Similarly, PVL (calculated from changes in haematocrit) and LA responses to exercise were increased with increasing workload. No direct relationship was found between PAVP changes and PVL or LA responses to submaximal exercise (p greater than 0.05). These results suggest that (a) PAVP levels increase to exercise with a response related to exercise intensity; (b) the stimuli generated directly or indirectly to exercise may be one of many factors causing an increase in PAVP.
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