MacIntosh Brian R, Murias Juan M, Keir Daniel A, Weir Jamie M
Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.
School of Kinesiology, Western University, London, ON, Canada.
Front Physiol. 2021 Sep 22;12:682233. doi: 10.3389/fphys.2021.682233. eCollection 2021.
A variety of health benefits associated with physical activity depends upon the frequency, intensity, duration, and type of exercise. Intensity of exercise is the most elusive of these elements and yet has important implications for the health benefits and particularly cardiovascular outcomes elicited by regular physical activity. Authorities recommend that we obtain 150min of moderate to vigorous intensity physical activity (MVPA) each week. The current descriptions of moderate to vigorous intensity are not sufficient, and we wish to enhance understanding of MVPA by recognition of important boundaries that define these intensities. There are two key thresholds identified in incremental tests: ventilatory and lactate thresholds 1 and 2, which reflect boundaries related to individualized disturbance to homeostasis that are appropriate for prescribing exercise. VT2 and LT2 correspond with critical power/speed and respiratory compensation point. Moderate intensity physical activity approaches VT1 and LT1 and vigorous intensity physical activity is between the two thresholds (1 and 2). The common practice of prescribing exercise at a fixed metabolic rate (# of METs) or percentage of maximal heart rate or of maximal oxygen uptake (V̇Omax) does not acknowledge the individual variability of these metabolic boundaries. As training adaptations occur, these boundaries will change in absolute and relative terms. Reassessment is necessary to maintain regular exercise in the moderate to vigorous intensity domains. Future research should consider using these metabolic boundaries for exercise prescription, so we will gain a better understanding of the specific physical activity induced health benefits.
与体育活动相关的各种健康益处取决于运动的频率、强度、持续时间和类型。运动强度是这些因素中最难捉摸的，但对健康益处，尤其是定期体育活动所带来的心血管健康结果具有重要影响。权威机构建议我们每周进行150分钟的中等至剧烈强度体育活动（MVPA）。目前对中等至剧烈强度的描述并不充分，我们希望通过认识定义这些强度的重要界限来加深对MVPA的理解。在递增测试中确定了两个关键阈值：通气阈值和乳酸阈值1和2，它们反映了与内环境稳态的个体化干扰相关的界限，适用于规定运动。VT2和LT2对应于临界功率/速度和呼吸补偿点。中等强度体育活动接近VT1和LT1，剧烈强度体育活动介于两个阈值（1和2）之间。以固定代谢率（代谢当量数）或最大心率百分比或最大摄氧量（V̇Omax）规定运动的常见做法没有考虑到这些代谢界限的个体差异。随着训练适应的发生，这些界限将在绝对和相对方面发生变化。为了保持在中等至剧烈强度范围内的定期运动，重新评估是必要的。未来的研究应考虑使用这些代谢界限进行运动处方，这样我们将更好地理解特定体育活动所带来的健康益处。
