a Biology of Physical Activity, Faculty of Sport and Health Sciences, University of Jyväskylä, PO Box 35, 40014 Jyväskylä, Finland.
b Institute of Exercise Physiology and Wellness, University of Central Florida, PO Box 161250, Orlando, FL 32816-1250, USA.
Appl Physiol Nutr Metab. 2017 Dec;42(12):1330-1340. doi: 10.1139/apnm-2017-0279. Epub 2017 Aug 21.
Diet composition influences acid-base status of the body. This may become more relevant as renal functional capacity declines with aging. We examined the effects of low (LD) versus high dietary acid load (HD) on blood acid-base status and exercise performance. Participants included 22 adolescents, 33 young adults (YA), and 33 elderly (EL), who followed a 7-day LD and HD in a randomized order. At the end of both diet periods the subjects performed a cycle ergometer test (3 × 10 min at 35%, 55%, 75%, and (except EL) until exhaustion at 100% of maximal oxygen uptake). At the beginning of and after the diet periods, blood samples were collected at rest and after all workloads. Oxygen uptake, respiratory exchange ratio (RER), and heart rate (HR) were monitored during cycling. In YA and EL, bicarbonate (HCO) and base excess (BE) decreased over the HD period, and HCO, BE, and pH were lower at rest after HD compared with LD. In YA and EL women, HCO and BE were lower at submaximal workloads after HD compared with LD. In YA women, the maximal workload was 19% shorter and maximal oxygen uptake, RER, and HR were lower after HD compared with LD. Our data uniquely suggests that better renal function is associated with higher availability of bases, which may diminish exercise-induced acidosis and improve maximal aerobic performance. Differences in glomerular filtration rate between the subject groups likely explains the larger effects of dietary acid load in the elderly compared with younger subjects and in women compared with men.
饮食结构会影响身体的酸碱平衡状态。随着年龄的增长，肾功能下降，这种影响可能会更加明显。我们研究了低（LD）与高（HD）饮食酸负荷对血液酸碱平衡状态和运动表现的影响。参与者包括 22 名青少年、33 名年轻成年人（YA）和 33 名老年人（EL），他们以随机顺序分别进行了为期 7 天的 LD 和 HD 饮食。在两种饮食期结束时，受试者都进行了自行车测力计测试（3×10 分钟，分别在 35%、55%、75%和（除了 EL 之外）直至 100%最大摄氧量的最大功率）。在饮食期开始前和结束后，在休息和所有工作量后采集血液样本。在骑自行车期间监测了氧气摄取量、呼吸交换比（RER）和心率（HR）。在 YA 和 EL 中，HCO 和 BE 在 HD 期间下降，并且与 LD 相比，HD 后休息时 HCO、BE 和 pH 较低。在 YA 和 EL 女性中，与 LD 相比，HD 后在亚最大工作量时 HCO 和 BE 较低。在 YA 女性中，最大工作量缩短了 19%，HD 后最大摄氧量、RER 和 HR 均低于 LD。我们的数据独特地表明，更好的肾功能与更多的碱基可用性相关，这可能会减轻运动引起的酸中毒并提高最大有氧表现。肾小球滤过率在受试人群之间的差异可能解释了与年轻人相比，老年人以及与男性相比，女性受到饮食酸负荷的影响更大的原因。
