Education And Debate

ABC of Sports Medicine : PULMONARY LIMITATIONS TO PERFORMANCE IN SPORT

BMJ 1994; 309 doi: https://doi.org/10.1136/bmj.309.6947.113 (Published 09 July 1994) Cite this as: BMJ 1994;309:113
  1. Mark Harries, is consultant physician, Northwick Park Hospital, Harrow, and director (honorary) of clinical services at the British Olympic Medical Centre, Harrow. The ABC of Sports Medicine has been edited by Greg McLatchie, visiting professor of sports medicine and surgical sciences at the University of Sunderland, consultant surgeon at Hartlepool General Hospital, and director of the National Sports Medicine Institute, London.a
  1. a The photograph of the women's coxless four in the Olympic regatta at Bayolas, Spain, in 1992 was taken by Peter Spurrier, Sports Photography; that of Liz McColgan in the 10 000 m heats at the Barcelona Olympics in 1992 by Professional Sport; and that of a step aerobics class by Richard J Sowersby.

    Assuming lung function to be normal, there is said to be no pulmonary limitation to aerobic performance. Justification for this statement rests with the fact that, while exercising at the maximum aerobic capacity (that is, when the rate of oxygen consumption cannot be further increased (VO2max)), it is possible to increase ventilation still more by voluntary effort. The main limiting factor is held to be a failure to match the rate at which muscle can consumes oxygen with the rate at which oxygenated blood can be delivered; in other words, the cardiac output.

    The lungs may be regarded as the carburetter of the engine, thus only when they are diseased—such as in chronic bronchitis or emphysema— does ventilatory capacity become reduced to the point where it limits exercise tolerance. Chronic bronchitis causes obstruction to air flow which, coupled with a reduction in vital capacity, results in a low ventilatory capacity or minute volume. Emphysema imposes an additional burden because not only is minute volume reduced but so also is oxygen transfer because of a loss of alveoli.

    Importance of high ventilatory capacity

    High ventilatory capacity is essential for sports such as rowing, cycling, and middle and long distance running. When exercised to maximum most elite athletes in their mid-20s reach a respiratory rate of around 55 breaths a minute with a heart rate of close to 200, regardless of their size. In absolute terms the highest minute ventilation is usually achieved by the biggest athletes, as breath volume is directly related to size. Indeed the highest so …

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