Cardiac Manifestations of Exhaustive Exercise in Nonathletic Adults: Does Cardiac Fatigue Occur?

Analysis and recognition of post-exercise cardiac state based on heart sound features and cardiac troponin I

PURPOSE

Excessive intensity exercises can bring irreversible damage to the heart. We explore whether heart sounds can evaluate cardiac function after high-intensity exercise and hope to prevent overtraining through the changes of heart sound in future training.

METHODS

The study population consisted of 25 male athletes and 24 female athletes. All subjects were healthy and had no history of cardiovascular disease or family history of cardiovascular disease. The subjects were required to do high-intensity exercise for 3 days, with their blood sample and heart sound (HS) signals being collected and analysed before and after exercise. We then developed a Kernel extreme learning machine (KELM) model that can distinguish the state of heart by using the pre- and post-exercise data.

RESULTS

There was no significant change in serum cardiac troponin I after 3 days of load cross-country running, which indicates that there was no myocardial injury after the race. The statistical analysis of time-domain characteristics and multi-fractal characteristic parameters of HS showed that the cardiac reserve capacity of the subjects was enhanced after the cross-country running, and the KELM is an effective classifier to recognize HS and the state of the heart after exercise.

CONCLUSION

Through the results, we can draw the conclusion that this intensity of exercise will not cause profound damage to the athlete's heart. The findings of this study are of great significance for evaluating the condition of the heart with the proposed index of heart sound and prevention of excessive training that causes damage to the heart.

Right Ventricular Diastolic Dysfunction after Marathon Run

It has been raised that marathon running may significantly impair cardiac performance. However, the post-race diastolic function has not been extensively analyzed. We aimed to assess whether the marathon run causes impairment of the cardiac diastole, which ventricle is mostly affected and whether the septal (IVS) function is altered. The study included 34 male amateur runners, in whom echocardiography was performed two weeks before, at the finish line and two weeks after the marathon. Biventricular diastolic function was assessed not only with conventional Doppler indices but also using the heart rate-adjusted isovolumetric relaxation time (IVRTc). After the run, IVRTc elongated dramatically at the right ventricular (RV) free wall, to a lesser extent at the IVS and remained unchanged at the left ventricular lateral wall. The post-run IVRTc_IVS correlated with IVRTc_RV (r = 0.38, p < 0.05), and IVRTc_RV was longer in subjects with IVS hypertrophy (88 vs. 51 ms; p < 0.05). Participants with measurable IVRT_RV at baseline (38% of runners) had longer post-race IVRTc_IVS (102 vs. 83 ms; p < 0.05). Marathon running influenced predominantly the RV diastolic function, and subjects with measurable IVRT_RV at baseline or those with IVS hypertrophy can experience greater post-race diastolic fatigue.

The effect of prolonged physical activity performed during extreme caloric deprivation on cardiac function

BACKGROUND

Endurance exercise may induce transient cardiac dysfunction. Data regarding the effect of caloric restriction on cardiac function is limited. We studied the effect of physical activity performed during extreme caloric deprivation on cardiac function.

METHODS

Thirty-nine healthy male soldiers (mean age 20 ± 0.3 years) were studied during a field training exercise lasted 85-103 hours, with negligible food intake and unlimited water supply. Anthropometric measurements, echocardiographic examinations and blood and urine tests were performed before and after the training exercise.

RESULTS

Baseline VO(2) max was 59 ± 5.5 ml/kg/min. Participants' mean weight reduction was 5.7 ± 0.9 kg. There was an increase in plasma urea (11.6 ± 2.6 to 15.8 ± 3.8 mmol/L, p<0.001) and urine osmolarity (692 ± 212 to 1094 ± 140 mmol/kg, p<0.001) and a decrease in sodium levels (140.5 ± 1.0 to 136.6 ± 2.1 mmol/L, p<0.001) at the end of the study. Significant alterations in diastolic parameters included a decrease in mitral E wave (93.6 to 83.5 cm/s; p = 0.003), without change in E/A and E/E' ratios, and an increase in iso-volumic relaxation time (73.9 to 82.9 ms, p = 0.006). There was no change in left or right ventricular systolic function, or pulmonary arterial pressure. Brain natriuretic peptide (BNP) levels were significantly reduced post-training (median 9 to 0 pg/ml, p<0.001). There was no elevation in Troponin T or CRP levels. On multivariate analysis, BNP reduction correlated with sodium levels and weight reduction (R = 0.8, p<0.001).

CONCLUSIONS

Exposure to prolonged physical activity performed under caloric deprivation resulted in minor alterations of left ventricular diastolic function. BNP levels were significantly reduced due to negative water and sodium balance.

Aberrant regulation of endogenous ouabain-like factor in bipolar subjects

Ill phases of bipolar illness are associated with abnormalities in ion regulation and intracellular ion concentrations. Previously, it has been reported that mania is characterised by lower circulating levels of ion regulating endogenous cardenolides, and that bipolar subjects lack the normal seasonal variation of these factors. Since endogenous cardenolides are elaborated in settings of extensive physical activity, euthymic bipolar and psychiatrically normal control subjects were asked to exercise to exhaustion. Plasma concentrations of endogenous cardenolides were measured at baseline, 60 min, peak exercise and post-recovery. Ouabain-like immunoreactive factor (OLF) was lower at baseline (0.005+/-S.D. 0.01 ng/mL in bipolar vs. 0.072+/-0.06 ng/mL in normal control subjects, P=0.019), lower at 60 min (0.007+/-S.D. 0.02 ng/mL in bipolar vs. 0.075+/-0.06 ng/mL in normal control subjects, P=0.029), and tended to be lower at peak exercise (0.009+/-S.D. 0.02 ng/mL in bipolar vs. 0.131+/-0.21 ng/mL in normal control subjects, P=0.15) in bipolar subjects compared to non-psychiatric controls. Other endogenous cardenolides did not vary significantly. The endogenous cardenolide, OLF, may be aberrantly controlled in bipolar illness.