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Glucose tolerance during moderate prolonged exercise in women with oral contraceptives as compared to non-users
N Boisseau1, F Rannou, P Delamarche
1Laboratoire de Physiologie et Biomécanique de l'Exercice Musculaire UFR-APS, Université de Rennes II, France. nathalieboisseau@hotmail.com
Background:
The purpose of this study was to assess gluco-se tolerance during exercise in women on oral contraceptives.
Methods:
To this end, we investigated the effects of glucose ingestion on glucose and hormonal responses in 7 women on oral contraceptives (OC(+); 21.3+/-1.3 yrs) and 7 normally menstruating (OC(-); 22.6+/-1.3 yrs) during an ergocycle test (30 min, 60% VO2max). Venous blood samples were withdrawn at 0, 3, 5, 10, 15 and 30 min exercise and at the 30th min postexercise. Glucose was ingested per os (0.5 g x kg(-1) b.w) between the 2nd and the 3rd min of the exercise.
Results:
Under resting condition, plasma glucose and catecholamine concentrations were similar in both groups whereas plasma GH and insulin levels were greater in OC(+) (p<0.05). Glucose/insulin ratio (G/I), used as an indicator of insulin resistance, suggested a reduced insulin sensitivity at rest in the OC(+) (p<0.05). No significant differences were observed between OC(+) and OC(-) in plasma glucose, insulin, and catecholamine concentrations during exercise. Plasma GH values were greater in OC(+) from the 15th min of the exercise and during the recovery period (p<0.01).
Conclusions:
This study indicated that oral glucose ingestion at the onset of prolonged submaximal exercise induced similar glucose tolerance in women taking or not oral contraceptives.