# Characteristics of energy metabolism and stress load in elite MOBA E-sports athletes

## TL;DR

This study examines how elite e-sports athletes' energy metabolism and stress levels change during different phases of a game, revealing insights into their physiological demands.

## Contribution

The study identifies phase-specific physiological responses in e-sports athletes, highlighting carbohydrate metabolism and autonomic nervous system dynamics during gameplay.

## Key findings

- Early-game increases energy expenditure, oxygen consumption, and carbohydrate oxidation with sympathetic-parasympathetic coactivation.
- Mid-game shows sustained carbohydrate dominance and partial parasympathetic recovery amid sympathetic predominance.
- Late-game features partial autonomic recovery and elevated neural fatigue indicators despite slight metabolic rebounds.

## Abstract

E-sports gained growing recognition as a competitive pursuit with quantifiable physiological demands. While previous studies have shown that cognitive stress modulates energy metabolism and autonomic nervous system regulation, phase-specific physiological responses during gameplay remain poorly understood.

20 elite League of Legends players (rank ≥ Platinum) were enrolled. Their cardiopulmonary function and autonomic nervous system activity were monitored during rest and across three distinct match phases (early-, mid-, and late-game). Energy metabolism parameters were measured using a portable cardiopulmonary testing system, and heart rate variability indices were assessed with a chest-worn monitor.

Compared with the resting state, the early-game elicited significant increases in energy expenditure oxygen consumption (VO2), carbon dioxide production (VCO2), and respiratory exchange ratio (all p < 0.001), with carbohydrate oxidation accounting for approximately 63% of total energy supply. Heart rate (HR) increased by 12.8%, while the root mean square of successive differences (RMSSD) rose by 52.2%, indicating sympathetic-parasympathetic coactivation. In the mid-game, metabolic indices declined but remained above baseline levels, characterized by sustained carbohydrate dominance (about 63.6%) and increased fat oxidation (about 30.2%); heart rate variability indices reflected sympathetic predominance accompanied by partial parasympathetic recovery. The late-game was characterized by slight rebounds in metabolic load and carbohydrate utilization (about 68.2%), accompanied by decreased Heart rate and elevated RMSSD, suggesting partial autonomic recovery alongside incipient neural fatigue.

Elite e-sports athletes demonstrate dynamic, phase-dependent alterations in energy metabolism and autonomic nervous system regulation. The early phase is characterized by carbohydrate-dominated physiological activation, the mid phase by metabolic stabilization amid sustained cognitive demand, and the late phase by partial autonomic recovery with cumulative neural fatigue. These findings highlight the physiological mechanisms underlying E-sports performance and provide actionable insights for optimizing training regimens, fatigue monitoring protocols, and recovery interventions.