1. Skipping Recovery Comes With Consequences
Under normal circumstances, your body is in a state of homeostasis. Everything runs along smoothly, and processes occur predictably.
The homeostatic state gets disrupted when you run into a stressor, such as an intense workout. Your body enters a state of alarm, where it’s recognized the stressor and mobilizes all forces to deal with it. In the context of training, the alarm phase leads to higher breathing rate, heartbeat, energy demands, and core body temperature, all necessary for allowing you to deal with the ‘threat.’
Once you’ve dealt with the stressor, your body enters the crucial recovery phase where it repairs the stress and damage. Training-related stress includes damage to the muscles, bones, joints, and connective tissues, along with central nervous system fatigue. So long as you give your body the time and resources it needs, the damage gets repaired, and you enter the last phase: adaptation.
Your body repairs the damage and makes the necessary improvements for handling the same stress better in the future. In the case of training, your body adapts to the specific training you do, leading to performance improvements, muscle gain, etc.
The problem is that skipping recovery prevents your body from repairing the accumulated damage and adapting positively. As a result, you run into recovery issues, fail to make progress, and put yourself at a higher risk of injury.