What is the difference between aerobic and anaerobic exercise?

Think of it like car engines: Aerobic is your efficient long-distance diesel engine. Anaerobic is your Formula 1 engine—incredibly powerful but guzzles fuel fast and can't run at max for long.

Practical signs: If you're breathing hard but steady and could keep going for 30 minutes it's aerobic. If you're gasping for air and have to stop after 30 seconds it's anaerobic. Your heart rate is also a clue: aerobic typically keeps you in 70-85% of your max heart rate while anaerobic pushes you to 85-100%. You need both! Aerobic exercise helps your body recover better from anaerobic sessions by improving circulation. And anaerobic exercise (like strength training) helps preserve muscle mass which keeps your metabolism higher even at rest. Don't choose one—do both for complete health.

This is a great foundation question in fitness! The core difference is in how your body produces energy. Aerobic means "with oxygen." During aerobic exercise (like jogging swimming cycling) your body uses oxygen to convert carbs and fats into energy. It's sustainable for longer periods (usually 2 minutes and beyond) at a moderate intensity where you can still talk. It primarily improves cardiovascular endurance.

Anaerobic means "without oxygen." During high-intensity short-burst activities (like heavy weightlifting sprinting HIIT) the demand for energy outstrips the oxygen supply. Your body switches to breaking down glucose without oxygen producing lactic acid as a byproduct. This causes that burning sensation and fatigue limiting the activity to short durations (seconds to about 2 minutes). It builds muscular strength power and size. In reality most activities have both components but one dominates. A balanced fitness program includes both: aerobic for heart health and stamina anaerobic for strength bone density and metabolism. The American Heart Association has excellent resources on aerobic exercise benefits.