Health · 7 min
Pregnancy calendar week by week — a guide
The three trimesters of pregnancy week by week: your baby’s development, changes in mum’s body and key tests. A practical calendar from week 1 to 40.
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Blog — page 13
Health · 6 min
Fertile days and ovulation — how to calculate them
How to work out your fertile days and ovulation date from your cycle length. We explain the fertile window, the luteal phase and show a worked example.
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Health · 6 min
BMI for children — percentile charts and norms
Why a child’s BMI is read from percentile charts rather than fixed thresholds. We explain percentiles, age norms and show an interpretation example.
· Redakcja Liczbnik
Health · 6 min
Body fat — how to calculate the percentage
Methods for measuring body fat: calipers, BIA and the Deurenberg formula from BMI. We explain the percentage norms and show a worked example.
· Redakcja Liczbnik
Health · 6 min
Blood pressure — norms and how to interpret them
What systolic and diastolic values mean, what the blood pressure norms are and when we talk about hypertension. A practical guide with a table of norms.
· Redakcja Liczbnik
Health · 5 min
Menstrual cycle — how to count its length
How to correctly count the length of your menstrual cycle, what regularity means and when cycle length warrants a consultation. A guide with an example.
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Sport · 6 min
VO2max — how to calculate it and what it says about fitness
What VO2max is, how to estimate it without a lab using your resting and maximum heart rate, and how to interpret the result. With a worked example.
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Sport · 5 min
One-rep max (1RM) — how to calculate it without risk
How to estimate your one-rep max (1RM) using the Epley formula from the number of reps. We explain the formula, show an example and the safety rules.
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Sport · 5 min
Water needs during training
How much water to drink before, during and after training. We explain how to estimate sweat losses and replace fluids and electrolytes. With an example.
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Science · 7 min
The Doppler Effect Explained — Formula, Examples and Calculator
What is the Doppler effect, how does the frequency-shift formula work and where is it used? From ambulance sirens to astronomical red-shift and medical ultrasound.
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Sport · 7 min
Training Volume Guide — How to Calculate Your Weekly Load
What is training volume, how do you calculate it and why does it determine your muscle growth? A practical guide to sets, reps, load and progressive overload for all levels.
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Finance · 8 min
Baby First Year Costs in Poland 2026 — Complete Guide
How much does it cost to have a baby and survive the first year in Poland in 2026? A complete breakdown of birth costs, baby gear, monthly expenses, childcare and government benefits.
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