[Lactate in cardiac rehabilitation]

Abstract

Background: Training increases work capacity and concomitantly quality of life, and also, according to new data, the life expectancy of patients with coronary heart disease and heart failure. At the same time, the importance of adequate training intensity increases aiming at low complications and high efficacy.

Assessment of exercise capacity: The objective of the present work is to define objective training guidance parameters in cardiac rehabilitation. Maximal exercise capacity must be distinguished from the performance without symptoms of oxygen deficit. The latter used to be early surpassed in untreated stabile angina pectoris. Within the last decade optimized therapy often yields a cardiac performance limit above the anaerobic threshold derived from lactate measurements. The concepts of aerobic and anaerobic thresholds derived from the lactate performance curve are introduced and modified leaving the 4 mmol/l lactate threshold concept to meet the criteria for performance capacity and breaking point in cardiac patients. The relationship to threshold concepts derived from spirometric data is mentioned as well as from stress hormones. The heart rate at the anaerobic threshold measured at treadmill ergometry systematically lies above the one from bicycle ergometry. Lactate increases faster with advancing age and the anaerobic threshold is earlier reached and progressively so because of the reduced muscle mass and reduced endurance capacity of people of the industrialized countries.

Importance: The determination of the anaerobic threshold as an objective criteria independent of motivation leads to training control, as shown by an example. Ineffective training above the threshold giving rise to catecholamines can be avoided by lactate performance diagnostic. Additionally, the success of rehabilitation measures can objectively be quantified and documented much better from the threshold work capacity than from maximal exercise tolerance. Preliminary reports indicate the importance of lactate diagnostics for rehabilitation guidance in heart failure.