Metabolic and cardioventilatory responses during a graded exercise test before and 24 h after a triathlon

Previous studies have reported respiratory, cardiac and muscle changes at r est in triathletes 24 h after completion of the event. To examine the effec ts of these changes on metabolic and cardioventilatory variables during exe rcise, eight male triathletes of mean age 21.1 (SD 2.5) years (range 17-26 years) performed an incremental cycle exercise test (IET) before (pre) and the day after (post) an official classic triathlon (1.5-km swimming, 40-km cycling and 10-km running). The IET was performed using an electromagnetic cycle ergometer. Ventilatory data were collected every minute using a breat h-by-breath automated system and included minute ventilation (V) over dot(E )), oxygen uptake ((V) over dot O-2), carbon dioxide production ((V) over d otCO(2)), respiratory exchange ratio, ventilatory equivalent for oxygen ((V ) over dot(E)/(V) over dotO(2)) and for carbon dioxide (V) over dot(E)/(V) over dotCO(2)), breathing frequency and tidal volume. Heart rate (HR) was m onitored using an electrocardiogram. The oxygen pulse was calculated as (V) over dotO(2)/HR. Arterialized blood was collected every 2 min throughout I ET and the recovery period, and lactate concentration was measured using an enzymatic method. Maximal oxygen uptake ((V) over dot O-2max) was determin ed using conventional criteria. Ventilatory threshold (VT) was determined u sing the V-slope method formulated earlier. Cardioventilatory variables wer e studied during the test, at the point when the subject felt exhausted and during recovery. Results indicated no significant differences (P > 0.05) i n (V) over dotO(2max) 162.6 (SD 5.9) vs 64.6 (SD 4.8) ml . kg(-1) . min(-1) ], VT [2368 (SD 258) vs 2477 (SD 352) ml . min(-1)] and time courses of (V) over dot O-2 between the pre- versus post-triathlon sessions. In contrast, the time courses of HR and blood lactate concentration reached significant ly higher values (P < 0.05) in the pri-triathlon session. We concluded that these triathletes when tested 24 h after a classic triathlon displayed the ir pre-event aerobic exercise capacity, bud did not recover pretriathlon ti me courses in HR or blood lactate concentration.