Fitness

Around the mid-30s, on average. A Karolinska Institutet study that followed 427 Swedes born in 1958 from age 16 to 63 found that aerobic fitness and muscular endurance peaked between ages 26 and 36, and performance began declining around age 35; explosive muscle power peaked even earlier. The decline starts slowly and speeds up with … Read more

Concentric contractions shorten a muscle under load; eccentric contractions lengthen it under tension—both are isotonic.

HIIT alternates short bursts of higher-intensity exercise with recovery periods, typically aiming for more than about 70% of maximum heart rate, in sessions often lasting 10–30 minutes plus warm-up and cool-down.

Aim for about 90 seconds per muscle group. A 2019 systematic review found 90 seconds was the minimum dose that reliably reduced short-term muscle soreness; range-of-motion gains were brief.

Brisk walking counts as cardio when it is moderate intensity—heart rate up, talking ok but not singing. Adults need 150 minutes/week of moderate aerobic activity; a slow stroll is usually light activity.

Electrolytes are charged minerals such as sodium, potassium, and calcium that help control the body’s water and pH balance, muscle and nerve function, heart rhythm, and blood pressure.

Sometimes, but mostly in the first days of high-dose loading, and mainly as water stored inside muscle; longer training studies show little lasting change in body water.

A Tabata workout is 20 seconds of near-maximal effort and 10 seconds of rest, repeated about eight times for four minutes, based on Izumi Tabata’s 1996 study.

A good VO2 max for many healthy adults is roughly 35–55 mL/(kg·min), varying by age, sex, and training.

A half marathon is 21.0975 kilometers, or about 13.1 miles (13 miles 192.5 yards), exactly half the distance of a full marathon. It is often called a 21K or 21.1K, and races are frequently held alongside a full marathon on a shortened version of the same course. World Athletics recognizes official records at the distance; … Read more