Every trainer has a favourite answer. Here's what research shows when you put the contenders side by side.
Calorie Burn Per Hour (160 lb person)
- Running 6 mph: ~600 cal
- HIIT: ~500-700 (including afterburn)
- Cycling moderate: ~500 cal
- Circuit training: ~400-500 + afterburn
- Strength training: ~300-400 + 24h afterburn
- Brisk walking: ~300-350 cal
- Yoga vinyasa: ~250-400 cal
Why HIIT Is Most Time-Efficient
20-minute HIIT produces comparable cardiovascular benefit to 40 minutes of steady cardio. EPOC (afterburn) is higher than any other modality. Limit: high injury risk makes daily HIIT unsustainable — 2-3 sessions/week is the evidence-based ceiling.
Why Strength Training Wins Long-Term
10 lbs of additional lean muscle burns ~60 extra calories/day at rest — 21,900 extra calories/year — equivalent to ~6 lbs of fat loss from the metabolic boost alone, before any extra exercise.
The Optimal Weekly Protocol
2-3 resistance training sessions as foundation + 2-3 cardio sessions (HIIT or moderate) + daily low-intensity movement (walking). This is the structure Adele's trainer reportedly used: circuit training with integrated cardiovascular elements.
The Most Important Factor
Adherence. A 30-min walk every day produces dramatically better results than an intense programme abandoned after 3 weeks.