Abstract
The aim was to assess the cardiac, arterial oxygen saturation, lactate, hormonal and
Borg rating of perceived exertion (RPE) responses to acute apnea in relation to apnea
capacity in 18 middle-aged triathletes. Subjects were monitored while swimming two
50-m freestyle exercise trials with fins at maximal speed: with normal frequency breathing
(NB) and with complete apnea (Ap); the latter was used to assess apnea capacity. The
subjects with significant alteration in swimming performance inducing a time increase
greater than 2.5% during Ap vs. NB were put in the group: bad apnea capacity (Bad
Ap); the others, who showed no significant alteration in performance, were put in
the group: Good Ap. Under apnea, both groups showed a decrease in arterial oxygen
saturation (p<0.05). In Ap conditions, only Bad Ap had a significant lower maximal
heart rate vs. NB (p<0.05), with lower blood lactate (p<0.05) and arm stroke frequency
(p<0.01). No change in saliva hormonal concentrations was found during the experiment
for both groups, whereas RPE responses were increased in the Good Ap group under Ap
vs. NB conditions. In conclusion, a good apnea capacity seems to be associated with
lower cardiovascular and metabolic apnea alterations in middle-aged recreationally-trained
triathletes.
Key words
acute dynamic apnea - heart rate - lactate - pulse oximetry - RPE
