Question 1

What is the lactate threshold, and what is lactate actually doing?

Accepted Answer

The intensity above which **lactate appears in the blood faster than it can be cleared**, so it accumulates. It is one of the best predictors of endurance performance — and almost everything people believe about lactate itself is wrong.

**The myth first.** Lactate does **not** cause muscle burn, does **not** cause next-day soreness, and is **not** a waste product. It is a **fuel**. Muscles produce it constantly, including at rest, and it is shuttled to other muscle fibres, the heart, the liver and the brain to be used for energy. Production rises with intensity because it is part of how fast energy is supplied, not because something has gone wrong.

**What actually causes the burning sensation** is a combination of hydrogen ion accumulation, inorganic phosphate and other metabolic changes. Lactate happens to rise alongside these, which is how it acquired the blame — a correlation mistaken for a cause for most of a century.

**Why the threshold matters.** Below it, lactate production and clearance are balanced, and you can sustain the effort for a long time. Above it, accumulation forces you to stop within minutes. **That crossover point determines how fast you can go for an hour**, which is why it predicts endurance performance better than VO2 max does among trained athletes.

**How it is measured:**

**Blood lactate testing** — a step test with finger-prick samples, the reference method.

**Critical power or critical speed** testing, from a set of maximal efforts.

**Functional threshold**, estimated from a sustained time trial — the practical field approach.

**Talk test** — approximately, the highest intensity at which you can still speak in full sentences.

**How it improves.** Both high-volume easy training and targeted work near threshold raise it, and the two do different things. The consistent finding across endurance sports is that **most training should be well below threshold**, with a small proportion hard — the polarised distribution.

**It moves independently of VO2 max**, which is why athletes with similar maximal capacity perform very differently.

Question 2

Why am I most sore two days after a workout?

Accepted Answer

That delay is the defining feature of delayed onset muscle soreness (DOMS). It typically begins 12–24 hours after training, peaks around 24–72 hours, and fades within about five to seven days. It is

Question 3

What is EPOC, and is the 'afterburn effect' real?

Accepted Answer

EPOC — excess post-exercise oxygen consumption — is the elevated metabolic rate that persists after exercise while the body restores itself. It is real, it is measurable, and the fat-loss claims

Question 4

Does fasted cardio burn more fat?

Accepted Answer

It burns a higher proportion of fat during the session, and this does not translate into greater fat loss over time. The distinction between substrate use and fat loss is where the entire claim falls

Question 5

What is zone 2 training, and why has it become so popular?

Accepted Answer

Training at a low, sustainable intensity — roughly the top of the range where you can hold a conversation — for long durations. It has become fashionable recently, but it is not new: it is what

Question 6

What is sarcopenia, and when does muscle loss actually start?

Accepted Answer

The age-related loss of muscle mass, strength and function — and the important correction is that meaningful decline starts far earlier than most people assume, and that strength is lost faster than

Question 7

Does cardio interfere with strength and muscle gains?

Accepted Answer

It can — the phenomenon is called the interference effect — but the magnitude depends heavily on how much, what type, and how it is scheduled, and for most people training recreationally it is small

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