Abstract
Pulmonary diffusion capacity has been observed to be reduced by approximately 14%
2h after 4-6 min of maximal exercise. The purpose of this study was to determine if
the decrease in pulmonary diffusion capacity also occurs when the duration of exercise
intensity is shorter or when the exercise intensity is lower. We measured pulmonary
diffusion capacity using the single breath method in 12 competitive rowers 22 (16-31)
years old, 70 (56-100) kg body weight, and 180 (171-193) cm body height under two
conditions: (1) 2h after 6 min of rowing at both 61% (58%-68%) and 76% (73%-78%) of
maximal oxygen uptake; (2) 2h after 1, 2, or 3 min of all-out rowing. Values are presented
as medians with ranges. Pulmonary diffusion capacity was reduced by 6% (2%-17%) after
6 min of rowing at 61% and by 10% (-7%-21%) after 6min of rowing at 76% of maximal
oxygen uptake (p<0.03). Pulmonary diffusion capacity was reduced by 7%(3%-19%), 8%(2%-17%)
and 7% (1%-16%) after 1, 2, and 3min of all-out rowing (p<0.01). We conclude that
submaximal exercise at 61% of maximal oxygen uptake will affect pulmonary diffusion
capacity following exercise as will shorter duration of maximal exercise. Although
the mechanism for this fall in pulmonary diffusion capacity is unclear, the fact that
it occurs after even mild exercise makes a significant change in pulmonary capillary
membrane integrity or subclinical pulmonary edema unlikely. Rather, we suggest that
a fall in central blood volume might explain the decrease in pulmonary diffusion capacity
following exercise.
Key words
Exercise - duration - intensity - lactate - rowing
