In 2025, fitness science has shifted away from declaring a single “best” exercise, instead emphasizing a hybrid approach tailored to specific goals like longevity, fat loss, or heart health.
The most effective strategy currently recognized by experts is a combination of Zone 2 steady-state cardio for a healthy aerobic base and Zone 5 high-intensity training for peak cardiovascular capacity.
1. Best for Longevity: Zone 2 Cardio
Zone 2 training (exercising at 60–70% of your maximum heart rate) is widely cited as the “foundation” for a long, healthy life. At this intensity, you can still hold a conversation but are clearly exerting effort.
- Why it works: It improves mitochondrial density and efficiency, allowing your body to use fat and oxygen more effectively.
- Recommended Dose: Aim for 150–300 minutes per week.
- Top 2025 Activities: Brisk walking, light jogging, cycling, or swimming.
2. Best for Fat Loss: HIIT (Zone 5)
High-Intensity Interval Training (HIIT) remains the most efficient way to burn fat in a short timeframe. It involves short bursts of maximum effort (Zone 5) followed by brief recovery periods.
- Why it works: It triggers the “afterburn effect” (EPOC), keeping your metabolism elevated for hours after the workout ends.
- Recommended Dose: Only 1–2 sessions per week to prevent overtraining and joint stress.
- Top 2025 Activities: Sprints, assault bike intervals, kettlebell swings, and rowing.
3. Best Low-Impact Options
For those with joint concerns or recovering from injury, low-impact cardio provides the same heart benefits as high-impact running without the “pounding” on bones.
- Swimming: A full-body workout that is gentle on joints and excellent for lung capacity.
- Rowing: Engages 85% of your body’s muscles and is a high-calorie burner.
- Incline Walking: Specifically the “12-3-30” method (12% incline, 3 mph, 30 minutes) burns more calories than flat walking while being safer for the knees than running.
Summary: The “Ideal” Weekly Routine
Based on 2025 expert recommendations, a balanced plan for a healthy adult should look like this:
- 80% Zone 2: 3–4 sessions of steady-state activity (e.g., a 45-minute brisk walk or bike ride).
- 20% High Intensity: 1 session of vigorous intervals (e.g., 20 minutes of 30-second sprints).
- Consistency: The “best” cardio is ultimately the one you will perform consistently; even social activities like pickleball or dancing provide significant longevity benefits.