Affiliations: [a] Department of Clinical Chemistry, University and University Hospital of Liège, Belgium | [b] Department of Motility Sciences, University and University Hospital of Liège, Belgium | [c] Multidisciplinary Service of Sports Medicine and Traumatology - SPORTS2, University Hospital of Liège, Belgium | [d] Biostatistic Department, University of Liège, Belgium
Abstract: BACKGROUND: Regular physical activity is an important health
factor, but intense physical stress can increase the risk of heart disease. OBJECTIVE: Our aim was to determine the potential cardiac
repercussions of, and the oxidative stress resulting from a maximal
eccentric isokinetic exercise and a 1-hour treadmill run at 75% V˙
O2 max (maximal exercise done 6 weeks before). METHODS: Twelve young sedentary healthy subjects randomly performed
two tests separated by 6 weeks: 1) 3 sets of 30 maximal eccentric isokinetic
contractions of the quadriceps; 2) a 1-hour running on treadmill at 75%
V˙
O2max max. We drew blood samples just before each exercise (T1), and
just after (T2), 3 hours after (T3), and 24 hours after (T4) the end of each
exercise to measure cardiac and oxidative stress biomarkers. RESULTS: In the running group, we observed significant differences for
myoglobin (T3: 145 ± 80 μ g/L), creatinine kinase
(T4: 593 ± 350 mg/L), oxidized glutathione (T2: 22 ± 15.6 μmol/L), and highly sensitive cardiac troponin T, (T3: 0.051 ± 0.038 ng/mL). In the isokinetic group, we observed significant differences for
myoglobin (T3:1419 ± 2533 mg/L), creatine kinase (3303 ± 7159 mg/L),
and oxidized glutathione (T4:24 ± 14 μ mol/L). Between isokinetic
exercise and running, we observed significant differences for uric acid
(p< 0.05, running > eccentric), myoglobin (p< 0.05, ditto),
NT-proBNP (p< 0.05, ditto), hsTnT (p< 0.01, ditto), and oxidized glutathione
(p< 0.05). CONCLUSIONS: As cardiac biomarkers appear practically unmodified
after the isokinetic exercise, despite the considerable oxidative stress,
we suggest that the application of intense maximal eccentric isokinetic
exercise, when indicated, should be safe for most patients including those
whose cardiac status is unknown. On the other hand, the increase in cardiac
biomarkers observed after running, could reflect leakage of these
biomarkers from the cytosolic pool of cardiac cells, linked to membrane
damage, rather than the result of a major injury and hence running is
supposed to be a safe practice. However, since sudden death during running
has been previously described, assesment of the cardiac biomarkers and a
follow-up by a sport doctor is important especially if there is a cardiac
family history.
