Shorter but higher intensity workouts are gaining more credibility as healthier alternatives to endurance training. Here are a few excerpts from an article on interval training:
“A lot of the (benefits) from exercise are due to a stress response,” said Stephen Bailey, a sports sciences expert at the University of Exeter. “If you disturb your muscles, there’s an imbalance created and your body will start signaling pathways that result in adjustments.”
Shorter but more intense “stress responses” stimulate growth hormone levels while minimizing cortisol levels. By comparison, lengthy endurance training sessions maximize cortisol levels and paradoxically compromise muscle energy output in the long run (pun intended):
Bailey said intense bursts of exercise help the body to convert one type of muscle fiber into another type that uses oxygen more efficiently and is capable of exercising a lot longer. Even though interval training only takes a few minutes, its effects last for hours.
Finally, interval (power law) training builds lean muscle tissue that has a voracious appetite for both consumed and stored fat:
“You’ve exercised at such a high intensity that you’re going to create a massive disturbance in your muscles,” Bailey said. “That creates a higher metabolism for several hours afterward, which the body will bring down by burning fat and carbohydrates.”
Keep this in mind during your next 1.5 hour treadmill or spinning workout.