By sport
Swimming Training Zones
Pace per 100 m rules. Anchor to Critical Swim Speed (CSS) from a 400 m and 200 m time trial. Heart rate is hard to read in water.
Target Heart Rate Calculator
Your target heart rate for moderate exercise is 64 to 76% of your maximum heart rate, and 77 to 93% for vigorous exercise, with the maximum taken as 220 minus your age. For a 50-year-old that is 109 to 129 bpm moderate and 131 to 158 bpm vigorous. The American Heart Association draws the same bands lower, at 50 to 70% and 70 to 85%.
Fat Burning Zone Calculator
Fat oxidation peaks at roughly 74% of your maximum heart rate, not in the low band most gym equipment labels fat burn. For a 190 bpm maximum that is about 141 bpm, with fat oxidation staying near its peak from 129 to 150 bpm. Below that you burn a higher percentage of fat but fewer fat grams per minute.
Critical Swim Speed (CSS) Calculator
Critical Swim Speed is your swimming threshold pace, found from two time trials: CSS = 200 ÷ (t400 − t200) in meters per second, and pace per 100 m = 100 ÷ CSS. A 400 m in 6:00 and 200 m in 2:50 give a CSS of about 1.05 m/s, or roughly 1:35 per 100 m, your sustainable threshold pace.
Daily Calorie Calculator
Your daily calorie need is your basal metabolic rate (BMR) multiplied by an activity factor, giving total daily energy expenditure (TDEE). A 35-year-old man, 70 kg and 175 cm, has a BMR near 1,624 kcal. Training at a moderate level (factor 1.55), he needs about 2,517 kcal a day to maintain weight.
Carbohydrate Intake Calculator
Fuel by duration. Under an hour, water is usually enough (0 g/h). From 1 to 2.5 hours, aim for about 60 g of carbohydrate per hour from a single source. Beyond 2.5 hours, you can absorb up to 90 g/h using a glucose-to-fructose mix near 2:1. A 2-hour session needs roughly 120 g total.
Sweat Rate Calculator
Your sweat rate is the fluid you lose per hour of exercise. Weigh yourself before and after a session, add any fluid you drank, and divide by the time. Lose 1 kg in an hour while drinking 500 ml and your sweat rate is 1.5 L/h. On long efforts, replace roughly 100% to 150% of it.
VO2max Estimator
VO2max is the most oxygen your body can use per minute, the ceiling on your aerobic fitness. The 12-minute Cooper test estimates it from distance: VO2max = (meters - 504.9) / 44.73. Run 2,400 meters and you score about 42 ml/kg/min, a recreationally active level. A lab test is more exact, but this gets you close.
BMI Calculator
BMI is your weight in kilograms divided by your height in meters squared. At 70 kg and 175 cm your BMI is 22.9, inside the healthy range of 18.5 to 24.9. It is a fast population screen, but it counts muscle as mass, so lean, muscular athletes often read high.