Resistance training and cardiovascular exercise are both necessary for overall health, cognitive function, and maintaining muscle mass as we age.

I categorize exercise into strength training for muscle growth and endurance training for prolonged physical and mental performance.

You can build muscle strength and hypertrophy with weights ranging from 30% to 80% of your maximum, not just heavy weights.

To get stronger, focus on progressively increasing the loads you move; for hypertrophy, aim for localized, intense muscle contractions, and moving weights in the 30% to 80% range of your one repetition maximum is the most beneficial for muscle hypertrophy and strength.

Training to failure can lead to greater muscle growth but also increases fatigue significantly, so it's important to balance intensity and recovery. Going from some number of reps in reserve all the way to failure in a single mesocycle is a good practice for many, but not required; you can go two or three reps in reserve as long as you do enough sets to achieve close to ideal hypertrophy outcomes.

For strength training, a regimen of three to five compound exercises for three to five repetitions per set, with three to five minutes of rest, performed three to five times a week is effective. This approach allows for significant strength gains without excessive soreness.

Endurance can be built while maintaining or even increasing muscle size by incorporating one day of high-intensity interval training (HIIT) each week, such as 90-second all-out sprints followed by rest.

The rise of new fitness trends like Hyrox and hybrid training is largely due to the gap left by CrossFit's decline, as people seek more accessible fitness options.

Approximately 80% of resistance training should be below failure, with 20% at higher intensity to maximize benefits without causing damage.