# Heart Rate Variability in Basketball: The Golden Nugget of Holistic Adaptation?
###### Abstract  
The main aim of this narrative review is to assess the existing body of scientific literature on heart rate variability (HRV) in relation to basketball, focusing on its use as a measure of internal load and vagal nerve responses. Monitoring HRV offers insights into the autonomic function and training-induced adaptations of basketball players. Various HRV measurement protocols, ranging from short-term to longer durations, can be conducted in different positions and conditions, such as rest, training, and sleep, to determine this key metric. Consistency and individualization in measurement protocols, responding to the athlete's specific characteristics, is crucial for reliable HRV data and their interpretation. Studies on HRV in basketball have explored psychological adaptation, training effects, individual differences, recovery, and sleep quality. Biofeedback techniques show positive effects on HRV and anxiety reduction, potentially enhancing performance and stress management. The scientific literature on HRV in basketball could benefit from studies involving longer monitoring periods to identify significant trends and results related to training and recovery. Longitudinal HRV monitoring in teams with intense travel schedules could reveal the impact on athletes of all levels and ages, and, in this regard, individualized interpretation, considering the subjective recovery and fitness levels of athletes, is recommended to optimize training programs and performance. HRV provides insights into training and competitive loads, aiding in determining exercise intensities and training status. Additionally, HRV is linked to recovery and sleep quality, offering valuable information for optimizing player performance and well-being. Overall, HRV is a reliable tool for adjusting training programs to meet the specific needs of basketball players. HRV; basketball; recovery; adaptation; heart rate +
Footnote †: journal: applied sciences  
changes in athletes' ANS patterns can alter HRV patterns [7], aiding training professionals in managing fatigue and adjusting the exercise intensity [7], thus enabling dynamic periodization [8]. HRV monitoring has gained significant interest in team sports for reflecting changes in the autonomic function and training adaptations during the competitive season [9]. In basketball [10], a sport characterized by high-intensity efforts [11], HRV is crucial for managing executive functions during practice and competition [12], considering that effective basketball training aims to improve the physical and physiological condition of athletes by accurately recording, interpreting, and adjusting training loads [13]. Concretely, load demands can be categorized as the external load (EL), related to the volume and intensity, and the internal load (IL), which is the athlete's physiological response to these demands [14]. Specifically, the IL measures can be classified as subjective (the athletes' mental interpretation of stress) and objective (the monitored physiological responses) [15]. Among them, HRV (an objective measure) is typically monitored using HR sensors, straps, watches, wristbands, or rings that register beat-to-beat timing [16], indicating how athletes adapt to training, and has gained attention due to technological advancements in data collection. As a consequence, consistent and validated protocols are essential for effective decision-making using these data [17]. The impact of physical activity on HRV is well documented in numerous team sports [18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28]. Previous studies have investigated the role of HRV on recovery and readiness and as a load indicator. For instance, [PERSON] et al. [18] found differences in the HRV of female soccer players before high-demand matches. On the other hand, [PERSON] et al. [19] observed increased HRV in female volleyball players in the days leading up to competition. Conversely, [PERSON] et al. [21] found no effect of mindfulness training on the HRV of female soccer players. [PERSON] et al.