Maximise your endocrine response to training by working harder, resting less and keeping a high intensity/density to the work load. With significant loading parameters positive adaptations to all three energy systems can occur. That is, an increase in aerobic endurance without having to engage in long slow duration training. Lifting weights can increase aerobic endurance! There exists an infinite combination of movements, implements, loading protocols and rest intervals that can be manipulated to cause the required adaptations. Human beings have evolved an attitude that more is better – more money and more consumption. However, where training is concerned a focus on quality of workload over quantity is paramount. This is especially important if stress levels are high; i.e. not enough sleep, poor dietary choices, imbalanced work/life. Do the important compound movements; squats, pulls, pushes, lunges and some twisting with some real intensity for a maximum of 40 minutes and reap the rewards of improved body composition, increased efficiency of all three energy systems and less stress.