Estimation of plasma volume changes during marathon running.

Maughan, Ron; Whiting, P. H.; Davidson, R. J. L.

doi:10.1136/bjsm.19.3.138

Cited by 50 publications

(36 citation statements)

References 11 publications

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“…During a marathon, however, plasma volume decreased (Maughan et al 1985;Whithing et al 1984), as has also been found in an ultra-marathon over 67 km (Rehrer et al 1992). In longer ultra-endurance races, however, plasma volume increased Stuempfle et al 2003).…”

Section: Discussionmentioning

confidence: 54%

Low prevalence of exercise-associated hyponatremia in male 100 km ultra-marathon runners in Switzerland

Knechtle

Knechtle²,

Rosemann

2010

Eur J Appl Physiol

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We investigated the prevalence of exercise-associated hyponatremia (EAH) in 145 male ultra-marathoners at the '100-km ultra-run' in Biel, Switzerland. Changes in body mass, urinary specific gravity, haemoglobin, haematocrit, plasma [Na(+)], and plasma volume were determined. Seven runners (4.8%) developed asymptomatic EAH. Body mass, haematocrit and haemoglobin decreased, plasma [Na(+)] remained unchanged and plasma volume increased. Δ body mass correlated with both post race plasma [Na(+)] and Δ plasma [Na(+)]. Δ plasma volume was associated with post race plasma [Na(+)]. The athletes consumed 0.65 (0.30) L/h; fluid intake correlated significantly and negatively (r = -0.50, p < 0.0001) to race time. Fluid intake was neither associated with post race plasma [Na(+)] nor with Δ plasma [Na(+)], but was related to Δ body mass. To conclude, the prevalence of EAH was low at ~5% in these male 100 km ultra-marathoners. EAH was asymptomatic and would not have been detected without the measurement of plasma [Na(+)].

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Section: Discussionmentioning

confidence: 54%

Low prevalence of exercise-associated hyponatremia in male 100 km ultra-marathon runners in Switzerland

Knechtle

Knechtle²,

Rosemann

2010

Eur J Appl Physiol

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“…Transient expansion of plasma volume commonly is reported after endurance events (Fellmann 1992;Fellmann et al 1999;Maughan et al 1985;Milledge et al 1982). Probably plasma volume seems to behave differently after longer distances.…”

Section: Change Of Plasma Volume Due To Hormonal Changes?mentioning

confidence: 94%

“…An increase of plasma protein-especially albumin-might explain an increase in plasma volume. Maughan et al (1985) found after a marathon an increase of total protein and albumin as well as Mischler et al (2003) after a multistage ultraendurance trial. Mischler et al (2003) detected an increased albumin synthesis after day 4 of exercise by 15%, whereas protein concentration was decreased by 8% after the same day.…”

Section: Increased Protein Synthesis and Increase Of Plasma Volume?mentioning

confidence: 96%

The Effects of Running 1,200 km Within 17 Days on Body Composition in a Female Ultrarunner—Deutschlandlauf 2007

Knechtle¹,

Duff²,

Schulze³

et al. 2008

Research in Sports Medicine

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We describe the changes of body composition in the female overall winner of the Deutschlandlauf 2007 over 17 stages from the northeast to the southwest of Germany with average daily running stages of 70.9 km to cover the total distance of 1,200 km. Determined by bioelectrical impedance analysis, body mass (BM) increased, percent body fat (% BF) decreased, and percent body water as well as lean body mass (LBM) increased. Skeletal muscle mass and % BF as determined by an anthropometric method showed no changes. This data show, that this female runner achieved an excellent performance and that it is possible for a woman to beat all the men. This type of analysis provides a unique opportunity to gain insight into the physiological changes during multiday running in ultraendurance athletes.

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“…However, it is well-established that thirst perception is an insufficient means to match fluid losses during exercise. 28 In addition, a body mass reduction of 3% or even less during 16 km of walking or running under the extreme environmental condition of heat stress 29 or during a marathon 30 has been associated with a decrease in plasma volume. These studies suggest that restoration of fluids lost via sweating should be promoted during prolonged, moderate-intensity exercise in the heat to ensure cardiovascular and thermoregulatory stability.…”

Section: Discussionmentioning

confidence: 99%

Sodium Replacement and Plasma Sodium Drop During Exercise in the Heat When Fluid Intake Matches Fluid Loss

Anastasiou

Kavouras

Arnaoutis

et al. 2009

Journal of Athletic Training

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Context: Sodium replacement during prolonged exercise in the heat may be critically important to maintaining fluid and electrolyte balance and muscle contractility.Objective: To examine the effectiveness of sodium-containing sports drinks in preventing hyponatremia and muscle cramping during prolonged exercise in the heat.Design: Randomized crossover study.Patients or Other Participants: Thirteen active men. Intervention(s): Participants completed 4 trials of an exercise protocol in the heat (306C) consisting of 3 hours of exercise (alternating 30 minutes of walking and cycling at a heart rate of 130 and 140 beats per minute, respectively); a set of standing calf raises (8 sets of 30 repetitions); and 45 minutes of steep, brisk walking (5.5 km?h 21 on a 12% grade). During exercise, participants consumed fluids to match body mass loss. A different drink was consumed for each trial: carbohydrateelectrolyte drink containing 36.2 mmol/L sodium (HNa), carbohydrate-electrolyte drink containing 19.9 mmol/L sodium (LNa), mineral water (W), and colored and flavored distilled water (PL).Main Outcome Measure(s): Serum sodium, plasma osmolality, plasma volume changes, and muscle cramping frequency.Results: During both HNa and LNa trials, serum sodium remained relatively constant (serum sodium concentration at the end of the protocol was 137.3 mmol/L and 136.7 mmol/L, respectively). However, a clear decrease was observed in W (134.5 6 0.8 mmol/L) and PL (134.4 6 0.8 mmol/L) trials compared with HNa and LNa trials (P , .05). The same trends were observed for plasma osmolality (P , .05). Albeit not significant, plasma volume was preserved during the HNa and LNa trials, but a reduction of 2.5% was observed in the W and PL trials. None of the volunteers experienced cramping.Conclusions: The data suggest that sodium intake during prolonged exercise in the heat plays a significant role in preventing sodium losses that may lead to hyponatremia when fluid intake matches sweat losses.Key Words: endurance, fluid replacement, hydration, hyponatremia, plasma volume, sports drinks Key Points: N Under environmental conditions in which fluid intake matched body mass loss, relatively moderate amounts of sodium added to the hydration solution attenuated the decline in sodium concentration of plasma and preserved plasma volume at pre-exercise levels.N Sodium supplementation did not increase serum sodium even when participants consumed a carbohydrate-electrolyte drink containing 36.2 mmol/L sodium.N A relationship between sodium supplementation and the prevention of exercise-associated muscle cramps cannot be established from the environmental and exercise factors of this study.N Further research using appropriate exercise protocols is needed to clarify the effect of sodium supplementation on the propensity to cramp during exercise.

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Estimation of plasma volume changes during marathon running.

Cited by 50 publications

References 11 publications

Low prevalence of exercise-associated hyponatremia in male 100 km ultra-marathon runners in Switzerland

Low prevalence of exercise-associated hyponatremia in male 100 km ultra-marathon runners in Switzerland

The Effects of Running 1,200 km Within 17 Days on Body Composition in a Female Ultrarunner—Deutschlandlauf 2007

Sodium Replacement and Plasma Sodium Drop During Exercise in the Heat When Fluid Intake Matches Fluid Loss

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