Biomarkers in Sports and Exercise: Tracking Health, Performance, and Recovery in Athletes

Abstract

Biomarker discovery and validation is a critical aim of the medical and scientific community. Research into exercise and diet-related biomarkers aims to improve health, performance, and recovery in military personnel, athletes, and lay persons. Exercise physiology research has identified individual biomarkers for assessing health, performance, and recovery during exercise training. However, there are few recommendations for biomarker panels for tracking changes in individuals participating in physical activity and exercise training programs. Our approach was to review the current literature and recommend a collection of validated biomarkers in key categories of health, performance, and recovery that could be used for this purpose. We determined that a comprehensive performance set of biomarkers should include key markers of (a) nutrition and metabolic health, (b) hydration status, (c) muscle status, (d) endurance performance, (e) injury status and risk, and (f) inflammation. Our review will help coaches, clinical sport professionals, researchers, and athletes better understand how to comprehensively monitor physiologic changes, as they design training cycles that elicit maximal improvements in performance while minimizing overtraining and injury risk.

Figure 1.

Comprehensive approach to biomarker analysis. Assessing multiple aspects of biological function allows coaches and athletes to track performance, recovery, and health in an individualized, practical manner. Relying on multiple validated biomarkers increases sensitivity, allowing athletes to detect potential impacts of training, recovery, diet, etc., long term. Data from long-term biomarker analysis will enhance preventative detection of injury or negative effects on performance. Examples of options for well-studied biomarkers in each category are provided as suggested components of a customized panel.

Figure 2.

Suggested biomarker testing time points. ● represents suggested biomarker panel testing at diagnostic opportunities throughout off-season and during-season training. * represents competitive season during which both training and competition occur. ** represents peak competition season during which championship matches might occur. Suggested time points for biomarker testing include before and after each major shift in training. Frequent (2–3 tests) testing during rested, healthy periods in the off-season will provide baseline values for many biomarkers and will be important for providing individualized biomarker data. Testing is also recommended before and after at least 1 acute exercise bout or performance test in the middle of a training season to acquire data around optimal performance. Testing before and after an acute bout of exercise will also allow athletes to analyze variables that might be more meaningful as responsive to an acute bout rather than as a single value at rest. It is also recommended that flexibility be built in to test biomarkers around a major championship competition or acute injury event. Testing not just before and after such an event, but also at additional time points after the competition or injury will allow the athlete to assess a recovery response. Data from biomarkers should be analyzed with physiological and physical data to contextualize results. This approach will optimize sensitivity, precision, and accuracy.

Figure 3.

Exercise-induced muscle damage and inflammation are physiologically integrated. Biomarkers of skeletal muscle damage and inflammation often increase concurrently during exercise-induced muscle damage or injury that will negatively affect performance. Inflammation is a process that will follow initial tissue damage and lag during recovery.