Benefits: improved VO2 max, heart health, mitochondrial density, fat oxidation capacity, mood (endorphins, BDNF), longevity. The single best-studied intervention for long-term health is regular moderate aerobic exercise.
Anaerobic exercise
"Without oxygen." At high intensities where oxygen demand exceeds supply. Glucose is the primary fuel. Cannot be sustained long — produces lactate and fatigue.
Fuel: Glucose (glycolysis) + ATP-PCr system (very short bursts)
Heart rate: 80–100% of max HR. Can only be sustained seconds to ~2 minutes.
Duration: Seconds (sprint, max lift) to ~2 min. Builds strength, power, muscle mass.
Benefits: increased muscle mass, strength, bone density, metabolic rate, testosterone and growth hormone response, insulin sensitivity. After heavy resistance exercise, metabolic rate stays elevated for hours (EPOC — excess post-exercise oxygen consumption).
The lactate threshold: The intensity at which lactate production exceeds the body's ability to clear it — the transition from aerobic to predominantly anaerobic. Training this threshold (tempo runs, sustained efforts just below max) is the most powerful tool for improving athletic performance. World-class endurance athletes have extremely high lactate thresholds — they operate aerobically at intensities that would be anaerobic for most people.
Part B · metabolism — how your body accounts for energy
Calculate your estimated daily energy needs
The calorie balance equation: Weight change = calories in − calories out. Fat: 1 kg of body fat ≈ 7,700 kcal. A 500 kcal/day deficit = ~0.5 kg/week loss. A 500 kcal/day surplus = ~0.5 kg/week gain. This is the physics — but metabolism adapts (BMR drops with sustained deficit, rises with sustained surplus), so the relationship is not perfectly linear over time.
Part C · the compound lifts — the foundation of strength training
Part D · breathing — when to inhale, when to exhale, why it matters
The universal rule for resistance training
Inhale on the eccentric phase
The eccentric is the lowering/lengthening/easier phase — where you're resisting gravity. Breathe in here. Examples: lowering the bar to chest in bench press; descending into a squat; lowering yourself on a pull-up; descending in a deadlift.
Exhale on the concentric phase
The concentric is the lifting/shortening/harder phase — where you're doing the work against gravity. Breathe out here. Examples: pressing the bar up in bench; standing up from a squat; pulling yourself up on a pull-up; lifting the bar in a deadlift.
Why this matters — intra-abdominal pressure (IAP): Exhaling during the hardest part of a lift (concentric) reduces intra-abdominal pressure, which reduces spinal stability — making the lift weaker and increasing injury risk. The technical technique for heavy lifting is the Valsalva manoeuvre: take a deep breath, brace your core hard (like you're about to be punched), hold the breath through the sticking point of the lift (the hardest moment), then exhale as you complete the rep. This creates maximum IAP and spinal stability.
Squat breathing cue
Inhale and brace before descent. Hold breath through the bottom and begin exhale as you drive up. Complete exhale at top. Reset breath each rep for heavy sets.
Deadlift breathing cue
Stand tall, take a deep breath, brace 360° around your torso. Initiate the pull. Begin exhale as bar passes knees. Exhale fully at lockout. Lower the bar, reset.
Light/cardio breathing
For lighter weights and cardio: breathe naturally in rhythm with the movement. Don't hold breath. For running: try 2-count or 3-count breathing (inhale for 2–3 strides, exhale for 2–3 strides).
Part E · protein — how much, why, and when
Protein target calculator — enter your weight
The science of muscle growth — what actually drives it
The signal: mechanical tension
Mechanical tension (load on the muscle, especially under stretch) is the primary driver of hypertrophy. When a loaded muscle is stretched under tension (the eccentric phase), mechanosensors in the muscle fibre detect this and trigger the anabolic signalling cascade (mTOR pathway).
The process: muscle protein synthesis
Exercise triggers muscle protein synthesis (MPS) — the construction of new protein to repair and add to muscle fibres. MPS is elevated for 24–48h after resistance exercise. Without adequate dietary protein, the body can't build the new tissue regardless of training stimulus.
The limit: genetics and testosterone
Natural muscle gain: ~0.5–1 kg/month for beginners, ~0.25–0.5 kg/month intermediate, ~0.1–0.25 kg/month advanced. Men gain faster than women (testosterone). Genetic ceiling exists — "natural" bodybuilders hit a ceiling set by their genetics and hormone profile.
Protein timing — does it matter?
The "anabolic window" (eat protein immediately post-workout) is largely a myth for people eating adequate daily protein. Total daily intake matters far more than timing. That said, distributing protein over 3–4 meals maximises MPS — each meal should contain ~20–40g protein to optimally stimulate MPS.
Part F · recovery — the most undervalued variable
Why muscles grow on rest days, not training days
Training is the stimulus, not the adaptation
Exercise creates microscopic damage in muscle fibres (microtears — especially from eccentric loading). The repair process — which happens primarily during sleep and rest — makes the fibre thicker and stronger than before. Training without recovery produces more damage than repair. "Overtraining" is genuinely possible — it suppresses immune function, raises cortisol chronically, and can reverse progress.
Minimum recovery time by muscle group
48–72 hours between sessions for the same muscle
Large muscles (legs, back): 72h minimum between heavy sessions. Smaller muscles (arms, shoulders): 48h. High frequency (hitting a muscle 3x/week) works only if volume per session is lower. Signs of insufficient recovery: persistent soreness, performance declining session to session, disrupted sleep, mood changes, loss of motivation.
Sleep's role in muscle growth
~70–80% of growth hormone secreted in first sleep cycle
N3 sleep triggers the largest GH pulse of the day. GH drives tissue repair and protein synthesis. Consistently sleeping less than 7 hours: impaired recovery, lower testosterone (~10–15% reduction after one week of 5-hour nights), elevated cortisol, and reduced muscle protein synthesis. Sleep is arguably as important as training for body composition.
Progressive overload — the only principle that matters long-term
Gradually increasing the demand on the muscle
The body adapts to any given load and stops responding. Progress requires progressive overload: increasing weight, reps, sets, range of motion, or reducing rest time over time. Without it, training maintains but doesn't improve. The simplest implementation: add a small amount of weight (2.5–5 kg) when you can complete all reps of all sets with good form.
DOMS — delayed onset muscle soreness
Not an indicator of a good workout
DOMS peaks 24–72h after exercise, especially after eccentric-heavy movements or novel exercises. It is inflammation from microscopic damage — not a measure of training quality. You can have an excellent, muscle-building session with little DOMS (particularly as you become more trained). Chasing soreness is not a training strategy. DOMS is not related to lactic acid — that clears within ~30 min of exercise ending.
Overtraining vs underrecovery
Most "overtraining" is actually under-eating and under-sleeping
True overtraining syndrome (systemic physiological breakdown from excessive training volume) is rare in recreational athletes. More common: functional overreaching — a temporary state of fatigue where performance drops, usually from training hard while eating in a deficit and sleeping poorly. Fix: eat more, sleep more, reduce training volume temporarily. Signs of real concern: persistent performance decline, resting heart rate chronically elevated, mood disturbance, illness frequency.
Part G · test yourself
1. You weigh 80 kg and want to build muscle. You're currently eating 100g of protein per day. Is this enough, and what foods get you to the right amount?
No — 100g is insufficient for muscle building at 80 kg. The research consensus for muscle hypertrophy is 1.6–2.2g per kg of body weight per day. For 80 kg: 128–176g protein/day. The minimum meaningful target is 128g; 160g is a solid working target. The gap between 100g and 160g = 60g of additional protein daily. Practical sources per 100g of food: chicken breast (~31g), canned tuna (~25g), Greek yoghurt (~10g per 100g, or ~17g per 170g pot), eggs (~13g per 2 eggs), cottage cheese (~11g per 100g), lentils (~9g per 100g cooked), whey protein shake (~25g per scoop). A rough daily structure: 2 eggs at breakfast (13g), 150g chicken at lunch (46g), 170g Greek yoghurt as snack (17g), 150g salmon at dinner (45g) = 121g. Add a protein shake (25g) = 146g. This is achievable with deliberate food choices without supplements, though protein powder makes it much easier.
2. What is the difference between a squat and a deadlift — why do both exist, and which muscles does each primarily work?
They target overlapping but distinct movement patterns. The squat is primarily a knee-dominant pattern — the knee flexes and extends under load, with the torso relatively upright. Primary movers: quadriceps (front of thigh), glutes, with hamstrings and adductors supporting. The bar (or weight) is above the centre of mass, requiring upper back and core to stabilise. The deadlift is primarily a hip-dominant pattern — the hip hinges (bends), with the spine in a neutral position and the bar on the floor. Primary movers: hamstrings, glutes, erector spinae (lower back), with quadriceps helping to break the floor initially. Secondary: traps, lats (to keep bar close), forearms (grip). Why both exist: the squat develops anterior chain (quads) and vertical pushing power; the deadlift develops posterior chain (hamstrings, glutes, back) and pulling strength. Together they cover essentially all major lower body and hip muscles. A programme with both is more complete than either alone. A simple test: "does the knee travel forward over the toes?" — yes = squat-like. "Does the hip hinge backward?" — yes = deadlift-like.
3. What is EPOC and why does it make post-workout calorie calculations complicated?
EPOC (Excess Post-exercise Oxygen Consumption) is the elevated oxygen consumption — and therefore elevated calorie burn — that persists after exercise ends. After aerobic exercise, EPOC lasts 15–60 minutes and adds a modest number of calories (50–150 kcal). After high-intensity resistance training or HIIT, EPOC can last 24–48 hours and add 100–350 kcal. The complication for calorie tracking: fitness trackers and apps calculate calories burned during exercise based on the movement, but they don't account for EPOC. More importantly, heavy resistance exercise has a smaller "during exercise" calorie burn than cardio (because rest periods are included) but significantly larger post-exercise metabolic elevation. This is why pure calorie-during-exercise comparisons favour cardio but miss the long-term metabolic advantage of resistance training. The practical implication: two workouts with the same calorie burn during exercise may have very different total metabolic costs once EPOC is included.
4. Why does the number on the scale sometimes go up right after starting a new exercise program, even if you're eating correctly?
Several things happen simultaneously that can increase scale weight despite positive body composition changes. First, glycogen storage: exercise depletes muscle glycogen, and as the body adapts to regular training it stores more glycogen. Each gram of glycogen is stored with ~3g of water. Increased glycogen storage can add 1–3 kg of water weight within the first 2–4 weeks. Second, muscle inflammation: resistance training causes microscopic damage and inflammation that draws fluid into the muscle tissue (the "pump" partially, and post-exercise swelling). This inflammation peaks around 24–48h post-exercise. Third, muscle protein synthesis genuinely adds mass. This is slow (see Module text) but real. The scale captures all of these — fat, muscle, water, glycogen, food in the digestive tract. For this reason, bodyweight trending over 4+ weeks is more useful than daily measurement, and body measurements or progress photos are more informative than scale weight alone for tracking actual body composition change.
5. You've been lifting for 6 months and your progress has stalled — same weights, same reps. What is almost certainly wrong, and what should you change?
A plateau after 6 months almost always has one of three causes, often in combination. First and most common: absence of progressive overload. If you've been lifting the same weight for the same reps for months, the muscle has fully adapted to that stimulus and has no reason to grow further. Fix: systematically add small amounts of weight (2.5 kg) or reps each week, or add a set. Second: insufficient protein. Muscle growth requires building blocks. If you're not consuming 1.6–2.2g protein/kg/day, you can stimulate muscle all you want but can't build it. Fix: track protein for two weeks and hit the target. Third: insufficient recovery. If you're training hard but sleeping 6 hours, stressed, or undereating, the recovery gap limits adaptation. Fix: prioritise sleep, ensure calorie intake is at or above maintenance if building is the goal. A less common fourth: your programme needs structural change (adding volume, changing exercises to create novel stimulus, adjusting rep ranges). True overtraining causing a plateau is rare — the other three causes are far more common.