Effort
Perceived effort is information. It becomes more useful when paired with pace, duration and recovery.
Sports physiology without the jargon
Physiology describes how the body responds to work. For readers over 35, the useful question is often not how to imitate elite athletes, but how to understand effort, fatigue and adaptation in a personal context.
Key ideas
Adaptation
Change takes time and depends on a balance between stimulus, nourishment and rest.
Variability
Daily responses move with sleep, stress, illness, temperature and accumulated load.
When to seek clinical guidance
Chest discomfort, fainting, unusual breathlessness or a sudden change in exercise tolerance deserve qualified medical attention rather than online experimentation.