That depends on your goals. If you want to build muscle and strength, then strength training should be your focus.

This can lead to:

1. Improved physical performance and enhanced body composition.

2. Improved Bone Density: Strength training has been shown to increase bone density and improve bone health, which can help to reduce the risk of osteoporosis.

3. Improved Joint Function: Strength training can help to improve joint function by strengthening the muscles that support the joint, thus reducing the risk of injury.

4. Enhanced Mobility: Strength training can help to improve mobility and flexibility, allowing for greater range of motion and improved physical performance.

If you want to improve your aerobic capacity and cardiovascular health, then cardio should be your focus.

This can lead to:

1. Increased Endurance – Improved endurance can help you keep going for longer when exercising, helping you push yourself further and achieve better results.

2. Improved Mental Health – Cardio exercise releases endorphins that help to improve your mood, reduce stress, and help you relax.

3. Weight Loss – Regular cardio exercise burns calories and can help you to lose weight and reduce body fat.

4. Increased Energy – Regular cardio exercise can help to increase your energy levels and help you to stay more alert throughout the day.

Ultimately, it is best to use both strength training and cardio into a fitness routine to reap the most benefits.