The world's supply of fossil fuels has been dwindling for a long time. It's been easy to pretend this wasn't happening because there seemed to be an endless quantity of oil and gas reserves. How could we ever run out? All we had to do was drill another well or lay down another pipeline. But now it seems that ineffective public policies and naive consumer practices have amplified the effects of two critical factors: an exploding global population and surging demands of thriving new economies in formerly developing nations.

Energy conservation has become an important topic around the globe, in communities, nations, and confederations such as the European Union. Energy conservation is not only critically important for global stability. It also serves as an important metaphor for the health and well-being of individuals.

Physiologically, humans have their own energy conservation systems. For example, your heart rate is tightly regulated. If your heart beats too fast for too long, owing to ongoing stress or anxiety, it may ultimately break down. Other problems may develop. A racing heart requires a lot of oxygen to supply the energy for heart muscle cells. This precious fuel is always needed elsewhere, and symptoms may develop in the gastrointestinal or hormonal systems.

Human internal energy conservation also involves the use of glucose, your body's primary energy currency. Glucose is used by every cell in the body as an energy resource to power normal physiological processes. For example, your brain is the number one consumer of glucose. In a fasting adult model, up to 80% of the glucose manufactured from stored complex carbohydrates is used for brain metabolism.^1,2 If your glucose storage and supply mechanisms are not optimized, many systems, including your mental functioning, will suffer significant drop-offs.

Importantly, regular vigorous physical exercise, particularly strength-training, ensures your body's optimal use of energy resources. Strength=training causes your body to build lean muscle mass, which burns energy even when you're resting. One long-term result is that both your blood glucose levels and your blood insulin levels tend to flatten out.³ The result is a body that knows how to optimally burn glucose for energy, rather than a body that is out of synch and storing glucose as fat. The glucose you consume as complex carbohydrates gets used efficiently, and your body works much more effectively.

You don't need to lift heavy weights to get these long-term health-promoting benefits. Lifting weights that are heavy enough to provide a modest challenge is all that's needed. The simple rule of thumb is this - if you can easily do three sets of eight repetitions with the weight you're using, it's too light. Increase the weight slightly so that attempting to do three sets of eight repetitions is a little challenging. That will be the right weight for you for that particular exercise.

Energy conservation is not only needed in the world today. The practice of energy conservation is also key for our internal health and well-being. Regular vigorous exercise helps us conserve the energy we need to live.

¹Tintinalli JE, et al: Emergency Medicine. A Comprehensive Study Guide, 6th ed. New York, McGraw-Hill, 2010, p 826

²McCormack SE, et al: Skeletal muscle mitochondrial function is associated with longitudinal growth velocity in children and adolescents. J Clin Endocrinol Metab Epub August 10, 2011

³Ryan AS: Exercise in aging: its important role in mortality, obesity and insulin resistance. Aging Health 6(5):551-563, 2010