| Summary: | 碩士 === 臺北醫學大學 === 傷害防治學研究所 === 103 === Objective:
To investigate cardiac function measurements and athletic performance by Noninvasive Method with Electrical Cardiometery among elite participants in 24 hour ultra-marathon.
Methods:
This is a prospective study, where twenty endurance athletes completed 24 hour runs on a 400m track. Cardiac function measurements were taken a day before, immediately after the race and 24 hour post race. All enrolled athletes than were classified into four groups according to 1.) Received intravenous hydration intervention or not, 2.) Total running distances greater than 200km or not, 3.) Body weight change greater than 3 percent or not, and 4.) Blood pressure declined over 10 percent or not. Both cardiac fatigue phase and recovery phase were than discussed in detail before all subjects divided into groups and after divided into groups, in order to assess cardiac function and performance.
Results:
Before stratify participants into groups, cardiac fatigue phase of all subjects is represented by a decline in left ventricular ejection time (289.7 ± 29.4 versus 257.6 ± 31.3 msec, P <0.002), an incline of cardiac output (4.3 ± 1.0 versus 5.4 ± 1.2 L/min, P =0.007) and heart rate at laying, seating and standing (64.2 ± 10.7 versus 81.5 ± 13.6 b P < 0.001; 66.1 ± 8.5 versus 86.2 ± 14.3 bpm, P <0.001; 73.2 ± 10.9 versus 92.8 ± 13.2 bpm, P <0.001). As well as body weight loss is observed (59.2 ± 6.1 versus 57.7 ± 5.9 kilograms, P < 0.001). Recovery phase is characterized by all cardiac function measurements and body weight returned back to baseline values. Even though this is not statistically significant, when breakdown each group individually, group 1 where athletes whom did not receive IV intervention showed a trend of a more senior marathon running experience (8.3 ± 6.4 vs 6.1 ± 3.1 years) along with a lower heart rate, pre-ejection period values and higher left ventricular ejection time with higher body weight loss were also seen in the non-intervention group. This may indicate that athletes in this group may not be approaching cardiac fatigue phase. In group 2, we have found that greater distance covered is associated with a decline in left ventricular ejection time (-45.92 ± 26.09 vs -6.29 ± 37.61, P=0.024) which when heart starts to fail this marker will begin to decrease. This in turn may be interpreted as prolong exercise will cause acute reversible clinically non-significant worsening in cardiac function. Interesting in group 3, we have found that performance is associated with greater body weight loss and participants with greater body weight loss have a lower thoracic fluid index (-0.71 ± 4.82 vs 3.38 ± 3.66, P = 0.046). This is a marker illustrating amount of fluid in the patient’s chest cavity, as a result this may be evidence demonstrating athletes with greater body weight loss have better cardiac function. In group 4, no evidence of suggesting clinically significant cardiac function changes were detected.
Conclusion:
Our current study indicates that the electric Cardiometry device is a useful device in measuring cardiac function during an ultramarathon setting. As well as, strenuous exercise will cause acute reversible clinically non-significant worsening in cardiac function.
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