Carpal tunnel syndrome (CTS) is caused by compression of a major nerve of the hand, and is the most common nerve injury of the upper limb. More commonly seen in PC gamers, irritation can result from a variety of causes ranging from mechanical keyboards, or repetitive use of the fingers and thumb. 

Initially, CTS presents with tingling in the fingers, numbness, and pain that occurs during or after gaming sessions, or upon awakening in the morning. A common complaint is feeling like you need to “shake out” the hands. If left untreated, the nerve begins to break down, causing the muscles it controls to respond slower and weaken. This makes finger and thumb movement difficult, interfering with the ability to quickly and efficiently reach keybinds and control a mouse or controller. 
Severe CTS may even prevent playing video games at all. League of Legends stars Uzi and Hai were both forced into early retirement due to arm and hand issues, citing constant pain prevented them from keeping up with the rigorous training schedules needed to compete at the professional level. 

Luckily, understanding of the complex nature of gamer health has evolved significantly since then, and this condition is entirely preventable with only a few simple tips.