Heart rate responses of a master athlete during ultra-endurance swimming

Abstract Aim: Swimming races outside swimming pools take place all over the world, but studies focusing on their physiological aspects are scarce. In fact, rules forbid any direct contact with swimmers during sanctioned events. This case report presents heart rate responses of a master athlete during an ultra-endurance open water solo swim and analyzes results based on a prior cardiopulmonary exercise test. Methods: The swimmer performed a cardiopulmonary exercise test on a treadmill, following a ramp protocol, with continuous electrocardiogram recording. The athlete performed a 36 km swimming race with continuous heart rate recording. Description of swimming heart rate accordingly to heart rate training zones and correlation analysis between HR and swim speed was assessed. Results: The athlete swam the 36 km event in 11 hours, 16 minutes and 15 seconds. Most of the swim time was spent in training zone 3 (55%), and only 2% of race time was spent in zone 5. Swimming speed (3.2 ± 0.7 km/h) failed to correlate with HR during the event (r2 = 0.1334, p > 0.05). Conclusion: Although HR did not correlate with swimming speed it successfully indicated exercise intensity during this 36 km event. These results can be used in the preparation and monitoring of other solo long-distance swimmers.

研究背景与目的：全球范围内各类公开水域游泳赛事蓬勃开展，但针对该类赛事生理层面的专项研究仍较为稀缺。事实上，在官方认证的公开水域游泳赛事中，赛事规则严禁工作人员与游泳选手发生直接身体接触。本病例报告记录了一名大师级运动员在36公里超长距离单人公开水域游泳赛事中的心率响应特征，并结合其此前完成的心肺运动试验（cardiopulmonary exercise test）对结果展开系统性分析。

研究方法：该运动员于跑台完成遵循递增负荷方案（ramp protocol）的心肺运动试验，试验全程持续记录心电图（electrocardiogram）数据。后续该选手完成了36公里的公开水域游泳赛事，期间全程持续记录心率数据。本研究依据心率训练区间对游泳过程中的心率分布特征进行描述，并评估了赛事期间心率与游泳速度之间的相关性。

研究结果：该运动员以11小时16分15秒的总成绩完成了36公里赛事。赛事过程中，其大部分游泳时间处于心率训练区间3（占比55%），仅有2%的赛事时间处于区间5。赛事期间游泳速度为3.2 ± 0.7 km/h，与心率未呈现显著相关性（r²=0.1334，p>0.05）。

研究结论：尽管心率与游泳速度未呈现显著相关性，但心率仍可有效反映本次36公里赛事中的运动强度水平。本研究结果可为其他单人长距离游泳选手的训练筹备与赛事监测提供参考依据。