📚 Health & Fitness Guides
In-depth, evidence-based guides on nutrition, exercise, and body composition. Written for real people, not textbooks.
🍎 Complete Guide to Calories, TDEE & Nutrition
Learn how calories work, calculate your TDEE, understand macronutrients, and build a sustainable nutrition plan.
Read guide →🏋️ Complete Guide to Fitness & Exercise
Heart rate zones, MET values, exercise types, workout planning, and the 80/20 training principle explained.
Read guide →📏 Body Composition Guide
Body fat percentage, ideal weight formulas, BMI limitations, and practical strategies to improve body composition.
Read guide →😴 Complete Guide to Sleep & Sleep Cycles
Sleep stages, 90-minute cycles, circadian rhythm, recommended sleep by age, and 15 evidence-based tips for better rest.
Read guide →🤰 Pregnancy Health Guide
Trimester milestones, nutrition needs, safe exercises, weight gain guidelines, prenatal vitamins, and warning signs.
Read guide →💧 Hydration & Water Intake Guide
Daily water needs, dehydration stages, electrolytes, hydration myths debunked, and practical tips to stay hydrated.
Read guide →Strength Training Guide: Building Muscle & Progressive Overload
Rep ranges, progressive overload, compound exercises, training splits, volume guidelines, and recovery essentials.
Read guide →Heart Rate Zones Guide: Fat Burn, VO2 Max & Training
5 training zones explained, the fat-burning zone myth, VO2 max, the 80/20 principle, and max heart rate formulas.
Read guide →Mental Health & Exercise Guide
How exercise reduces anxiety and depression, improves focus, boosts mood, and enhances sleep. Evidence-based recommendations.
Read guide →Related Calculators
Put the knowledge from these guides into practice with our free calculators:
- Calorie Calculator — Find your BMR and daily calorie needs
- Macro Calculator — Get your protein, carbs, and fat targets
- Body Fat Calculator — Estimate body fat % with the US Navy method
- Heart Rate Zone Calculator — Find your 5 training heart rate zones
- Ideal Weight Calculator — Compare 4 validated formulas
- Water Intake Calculator — Personalized daily hydration target
- Calorie Burn Calculator — Calories burned for 100+ activities
How to use the FitCalc health and fitness guides
The guides in this section pair with the calculators in FitCalc to give you both the number and the context behind it. A BMI value alone says little about an athlete's body composition. A target heart rate without an understanding of zones can lead to training that misses its purpose. A calorie target without macronutrient context can produce weight loss with poor body composition. Each guide explains the why behind the numbers so you can apply them sensibly.
Topics in this library
- Body composition — BMI, body-fat estimation methods, why waist-to-height ratio is often more informative than BMI, when to seek a DEXA scan.
- Cardiovascular training — heart-rate zones, lactate threshold, VO2 max, how to structure aerobic and anaerobic work across a week.
- Strength training — volume, intensity, frequency, progressive overload, programme structure across goals (strength, hypertrophy, endurance, power).
- Nutrition and hydration — energy balance, macronutrient ratios, micronutrient priorities, hydration during exercise and across climates.
- Recovery, sleep, and mental health — recovery markers, sleep architecture and exercise, the mental-health benefits of regular movement.
- Special populations — pregnancy, post-partum, older adults, and clinical contexts where standard advice needs adjustment.
Important note about medical advice
The guides in this library are educational and reflect mainstream consensus from sources such as the WHO, CDC, NHS, ACSM, and major peer-reviewed journals. They are not a substitute for individualised medical advice. If you have a chronic condition, are pregnant, are recovering from injury, or are considering significant changes to diet or exercise, consult a qualified clinician.