Effects of fasting and carbohydrate consumption on voluntary resting apnea duration
2007 (English)In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 100, no 4, 417-425 p.Article in journal (Refereed) Published
Breath holding is normally terminated due to the urge to breathe, mainly caused by the increasing carbon dioxide level. It was recently shown that a combination of 18 h of carbohydrate-free diet and prolonged exercise prior to breath holding lowered the respiratory exchange ratio (RER) and end-expiratory PO(2 )at maximal breath-hold break-point (MBP). Current hypothesis: fasting will result in longer breath-hold duration than will fasting followed by carbohydrate intake. It was also hypothesized that breath-holds during carbohydrate supplementation would be ended at a higher alveolar PO(2). Ten male non-divers performed multiple breath-holds either to the first diaphragmatic contraction (PBP), or to MBP. The breath-holds were performed during normal diet (control; C), twice during fasting (F14 h, F18 h), followed by post fasting carbohydrate consumption (PFCC) and a repetition of the breath-hold testing 1-2 h after ingestion of carbohydrates. Duration, RER, end-tidal PO(2) and PCO(2), SaO(2) and blood glucose were determined. RER and blood glucose increased after PFCC compared with fasting and control conditions (P < 0.001). PBP breath-hold duration increased from 129 +/- 34 s at C to 148 +/- 33 s at F18 h, and was reduced during PFCC to 122 +/- 30 s (P < 0.001). End-tidal PO(2) was higher at PFCC compared to F18 h (10.4 +/- 1.2 vs. 9.5 +/- 1.2 kPa at PBP, P < 0.05). Similar trends in breath-hold duration and physiology were seen in breath-holds that were terminated at MBP. Dietary restriction can affect breath-hold duration. The lower O(2) level at breakpoint during fasting suggests that breath holding may be less safe during fasting; the increased risk may be mitigated by ingestion of carbohydrates before breath holding.
Place, publisher, year, edition, pages
2007. Vol. 100, no 4, 417-425 p.
Apnea, Breath-hold, Diving, Drowning, Hypoxemia, Metabolism
IdentifiersURN: urn:nbn:se:kth:diva-45327DOI: 10.1007/s00421-007-0442-7ISI: 000246521100006PubMedID: 17406888OAI: oai:DiVA.org:kth-45327DiVA: diva2:452268
QC 201111162011-10-282011-10-282011-11-16Bibliographically approved