Oxygen Uptake, Acid-Base Balance and Anaerobic Energy System Contribution in Maximal 300 â€“ 400 M Running In Child, Adolescent and Adult Athletes

This study examines the neonatal response to graded hypoxia and determines the arterial PO2 (PaO2) threshold for oxygen-restricted metabolism as confirmed by the development of lactic acidosis and altered oxygen handling. Anesthetized, intubated, and ventilated 3-day-old pigs (n = 56) were randomly assigned to one of five predetermined acute (120 min) graded hypoxia groups: normoxia (PaO2 = 80 Torr) or mild (60 Torr), moderate (40 Torr), moderately severe (30 Torr), or severe (20 Torr) hypoxia. In moderate hypoxia, lactate and acid-base homeostasis were unaltered due to a significant increase in oxygen extraction (P < 0.05) that was sufficient to maintain the arteriovenous oxygen content difference (oxygen uptake). In moderately severe hypoxia, increased arterial lactate and decreased HCO3- and base excess were evidence of anaerobic metabolism, yet pH was unaltered, indicating adequate buffering. In this group, despite the increase in oxygen extraction, oxygen uptake was reduced, indicating the onset of oxygen-restricted metabolism. The severe hypoxia group had significantly increased lactate (21.7 +/- 3.9 mmol/l), decreased pH (7.01 +/- 0.07) and base excess (-21.5 +/- 3.0 mmol/l), and depletion of HCO3- (9.7 +/- 1.6 mmol/l) (P < 0.0001). Here, increases in oxygen extraction were severely limited by availability, resulting in significantly reduced oxygen uptake, anaerobic metabolism, and profound lactic acidosis.

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Detection of the change point in oxygen uptake during an incremental exercise test using recursive residuals: relationship to the plasma lactate accumulation and blood acid base balance

European Journal of Applied Physiology ◽

10.1007/s004210050433 ◽

1998 ◽

Vol 78 (4) ◽

pp. 369-377 ◽

Cited By ~ 20

Author(s):

Jerzy A. Zoladz ◽

Zbigniew Szkutnik ◽

Joanna Majerczak ◽

Krzysztof Duda

Keyword(s):

Oxygen Uptake ◽

Exercise Test ◽

Change Point ◽

Incremental Exercise ◽

Plasma Lactate ◽

Acid Base Balance ◽

Acid Base ◽

Incremental Exercise Test ◽

Base Balance ◽

Recursive Residuals

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Oxygen Uptake and Acid-Base Balance during Activity in Decapod Crustaceans

Locomotion and Energetics in Arthropods ◽

10.1007/978-1-4684-4064-5_12 ◽

1981 ◽

pp. 299-335 ◽

Cited By ~ 10

Author(s):

B. R. McMahon

Keyword(s):

Oxygen Uptake ◽

Decapod Crustaceans ◽

Acid Base Balance ◽

Acid Base ◽

Base Balance

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Higher Dietary Acidity is Associated with Lower Bone Mineral Density in Postmenopausal Iranian Women, Independent of Dietary Calcium Intake

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000207 ◽

2014 ◽

Vol 84 (3-4) ◽

pp. 0206-0217 ◽

Cited By ~ 8

Author(s):

Seyedeh-Elaheh Shariati-Bafghi ◽

Elaheh Nosrat-Mirshekarlou ◽

Mohsen Karamati ◽

Bahram Rashidkhani

Keyword(s):

Calcium Intake ◽

Dietary Calcium ◽

Dietary Calcium Intake ◽

Dietary Intakes ◽

Iranian Women ◽

Acid Base Balance ◽

Mineral Density ◽

Acid Base ◽

Base Balance ◽

Dietary Acid

Findings of studies on the link between dietary acid-base balance and bone mass are relatively mixed. We examined the association between dietary acid-base balance and bone mineral density (BMD) in a sample of Iranian women, hypothesizing that a higher dietary acidity would be inversely associated with BMD, even when dietary calcium intake is adequate. In this cross-sectional study, lumbar spine and femoral neck BMDs of 151 postmenopausal women aged 50 - 85 years were measured using dual-energy x-ray absorptiometry. Dietary intakes were assessed using a validated food frequency questionnaire. Renal net acid excretion (RNAE), an estimate of acid-base balance, was then calculated indirectly from the diet using the formulae of Remer (based on dietary intakes of protein, phosphorus, potassium, and magnesium; RNAERemer) and Frassetto (based on dietary intakes of protein and potassium; RNAEFrassetto), and was energy adjusted by the residual method. After adjusting for potential confounders, multivariable adjusted means of the lumbar spine BMD of women in the highest tertiles of RNAERemer and RNAEFrassetto were significantly lower than those in the lowest tertiles (for RNAERemer: mean difference -0.084 g/cm2; P=0.007 and for RNAEFrassetto: mean difference - 0.088 g/cm2; P=0.004). Similar results were observed in a subgroup analysis of subjects with dietary calcium intake of >800 mg/day. In conclusion, a higher RNAE (i. e. more dietary acidity), which is associated with greater intake of acid-generating foods and lower intake of alkali-generating foods, may be involved in deteriorating the bone health of postmenopausal Iranian women, even in the context of adequate dietary calcium intake.

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