Terms

The aerobic zone is the intensity at which energy is produced predominantly using oxygen, without significant lactic acid accumulation. Roughly zones 1-2 by heart rate.

The anaerobic threshold (lactate threshold) is the intensity above which lactic acid starts accumulating in the blood faster than the body can process it.

The anaerobic zone is high intensity (usually above 90% of maximum heart rate), at which energy is produced without sufficient oxygen, with rapid accumulation of lactic acid.

BMR (Basal Metabolic Rate) is the number of calories the body burns in a state of complete rest over a day — simply to maintain vital functions: breathing, heart function, body temperature.

A calorie (in nutrition, actually a kilocalorie, kcal) is a unit of measurement for the energy the body gets from food or spends on work, including running.

Carb loading is increased carbohydrate intake 1-3 days before a long race (marathon and longer) to maximally fill glycogen stores in the muscles before the race.

Compression clothing (calf sleeves, arm sleeves, shorts) fits tightly around the muscles, creating graduated pressure — stronger at the distal part of the limb and lighter closer to the body.

DOMS (Delayed Onset Muscle Soreness) is muscle pain that appears not immediately, but 24-48 hours after unfamiliar or intense exertion, especially after eccentric work (for example, downhill running).

Electrolytes are mineral salts (primarily sodium, as well as potassium and magnesium) that the body loses through sweat. Their imbalance during prolonged exertion in heat can cause cramps and weakness.

GPP is a set of exercises for general strength, flexibility, coordination, and endurance of stabilizer muscles, not directly tied to a specific sport.

Glycogen is the storage form of carbohydrates in the muscles and liver, the main "fast" fuel for intense physical work, including running.

Heart rate reserve is the difference between maximum heart rate and resting heart rate. The Karvonen method uses it to calculate zones more precisely than just a % of the maximum.

Heart rate zones are intensity ranges (usually 5 of them), expressed as a percentage of maximum heart rate, each corresponding to a specific type of training effect.

Macronutrients are proteins, fats, and carbohydrates: three groups of substances that give the body energy and building materials, as opposed to micronutrients (vitamins, minerals), which are needed in small doses.

Maximum heart rate is the highest number of heartbeats per minute the body is able to reach under maximal effort. The basis for calculating heart rate zones.

A negative split is a tactic in which the second half of the distance is run faster than the first. It is considered the most effective strategy for most race distances.

Overtraining is a state of chronic fatigue from accumulated training load without sufficient recovery, in which performance declines instead of improving, despite continued training.

PB (Personal Best) or PR (Personal Record) is your best personal result at a specific distance. It's one of the main sources of motivation in amateur running.

Resting heart rate is the heart rate at complete rest, best measured in the morning right after waking up, while lying down, before getting out of bed.

TDEE (Total Daily Energy Expenditure) is the total daily calorie expenditure: basal metabolism plus all physical activity, including training.

VO2max (maximal oxygen uptake) is the largest volume of oxygen the body is able to absorb and use per minute of intense work. A key indicator of aerobic fitness.