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Exp Clin Endocrinol Diabetes 1995; 103(3): 156-161
DOI: 10.1055/s-0029-1211344
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© J. A. Barth Verlag in Georg Thieme Verlag KG Stuttgart · New York

Increase of serum insulin and stable c-peptide concentrations with exhaustive incremental graded exercise during acute hypoxia in sedentary subjects

T. Kullmer1 , H. Gabriel2 , E. Jungmann1 , T. Haak1 , D. Morbitzer1 , K. H. Usadel1 , W. Kindermann2
  • 1Department of Internal Medicine, University of Frankfurt am Main, Germany
  • 2Institute of Sports- and Performance Medicine, University of Saarland, Saarbrücken, Germany
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Publication Date:
15 July 2009 (online)

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Summary

Hypoxia was shown to reduce insulin concentrations at rest and during exercise. However, some studies have also demonstrated increases in the hormone associated with arterial desaturation. This study was conducted in order to decide [1] whether acute alveolar hypoxia increased or decreased the circulating insulin levels, and [2] to elucidate whether interactions of insulin with other hormones were of relevance in this respect. Glucose (GLU), insulin (INS), c-peptide (CP), adrenaline and noradrenaline (CATs), atrial natriuretic peptide (ANP) and Cortisol (CORT) as well as the capillary blood gases were determined in 15 healthy fasting male volunteers (age: 26.2 ± 2.8 years, body mass index: 22.4 ± 2.7 kg • m—2). On two separate test days the subjects breathed, in random order, either normal air (N) or a gas mixture with reduced oxygen content (H; FIO2: 0.14). Measurements were made at rest as well as during an incremental cycle exercise in a supine position (increments of 6 min and 50 W) at 100 W and 150 W, at volitional exhaustion (N: 227 ± 36 W; H: 200 ± 32 W) as well as in the 5th min of recovery.

Arterial desaturation was seen throughout on H-day. At rest all hormones and GLU were normal and showed no influence of H. During exercise INS remained constant on N-day, increased on H-day and was significantly higher with H than with N, most pronounced at J 150 W and at volitional exhaustion with 20%, respectively. For CP and GLU no significant exercise-induced changes were seen on either test day and no influence of was detected. During exercise the CATs, CORT and ANP behaved normally on both test days and showed no significant influence of H.

When acute hypoxia is present, incremental exhaustive exercise on higher workloads can be associated with slightly augmented INS levels and with a temporary dissociation of INS and CP. Since INS and CP are released 1 in equimolar amounts, we conclude [1] that this suggests a temporary diminution of the clearance of circulating INS. [2] No influence of H was detected on the interactions of INS with other hormones.

Key words

Hormones - hypoxia - exercise

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