Exercise Physiology & Training
Load. Adapt. Perform.
Exercise physiology, training methods, programming, periodization, and performance.
3 notes
What fuel does the body use during exercise, and why does it change with intensity?
Muscle contraction is powered by ATP, which must be continually resynthesized through phosphocreatine, glycolytic and oxidative pathways. All contribute from the beginning, while their relative roles change with the rate of energy demand, exercise duration, training status and nutrient availability. Higher intensity generally increases reliance on muscle glycogen and carbohydrate, but there is no universal switch where fat suddenly turns off.
Lipolysis is not fat loss: what happens between mobilization and oxidation
Lipolysis releases fatty acids and glycerol from stored triglycerides. It does not guarantee that those fatty acids will be oxidized, nor that adipose tissue will be reduced over time. Fatty acids can circulate, enter different tissues, support signaling or synthesis, and be stored again. Fat loss is a cumulative outcome of fluxes across hours, days and weeks, not proof that one pathway was active during a workout.
HRV: read the trend, not the morning number
Heart rate variability is noisy day to day. Its value comes from your own normal range and from multi-day trends, not from reacting to a single reading. A low morning is information. A downward trend that lines up with poor sleep and a rising resting heart rate is a decision.