There is conflicting evidence'116 on the
effects of physical training on asthma. We
conclude that there is no significant change in
underlying disease severity for two reasons:
firstly, the improvement in FEV, seen in this
study could be explained by an increase in
prophylactic treatment in certain patients, particularly
as those who had their treatment
changed showed the greatest increases in FEV,
(six of those undergoing training had an
increase in dosage of prophylactic treatment,
compared with three control subjects);
secondly, there was no significant change in
non-specific bronchial responsiveness. This
contrasts with previous studies,'0 33 which
showed improvements in exercise induced
asthma after physical training. Increasing minute
ventilation during exercise is recognised as
the stimulus to exercise induced asthma,
regardless of whether the mechanism is respiratory
heat loss' or increased osmolarity due
to respiratory water loss.3" Our study suggests
that the reported improvements in exercise
induced asthma with training may be due to the
reduction in minute ventilation seen at high
work loads after training (fig 1) rather than a
change in underlying bronchial reactivity.
Thus the improvement in airflow obstruction
in individual patients in our view results from
optimisation of treatment arising as an indirect benefit of the continuous medical supervision
provided during the programme. Furthermore,
optimal treatment is likely to have
enhanced their ability to comply with training
requirements and highlights the importance of
having clinical expertise available during
physical training programmes.